third_party/webgl/specs/1.0/index.html - Issue 9360034: Remove everthing except conformance tests in the deps/third_party/webgl

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Issue 9360034: Remove everthing except conformance tests in the deps/third_party/webgl (Closed) Base URL: svn://chrome-svn/chrome/trunk/deps/

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1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"

2 "http://www.w3.org/TR/html4/strict.dtd">

3 <html lang="en">

4 <head>

5 <meta http-equiv="content-type" content="text/html; charset=utf-8">

6 <title>WebGL Specification</title>

7 <meta name="generator" content="BBEdit 9.1">

8 <link rel="stylesheet" type="text/css" href="../../resources/Khronos-Final.c ss" />

9 <script src="../../resources/jquery-1.3.2.min.js" type="text/javascript"></s cript>

10 <script src="../../resources/generateTOC.js" type="text/javascript"></script >

11 </head>

12 <body onload="generateTOC(document.getElementById('toc'))">

13 <!--begin-logo-->

14 <div class=head>

15 <p>

16 <a href="http://khronos.org/">

17 <img alt=Khronos height=60 src="../../resources/KhronosGroup-3D. png" width=220>

18 </a>

19 </p>

20 </div>

21 <div class=head>

22 <p>

23 <a href="http://webgl.org/">

24 <img alt=WebGL height=72 src="../../resources/WebGL-Logo.png" wi dth=156>

25 </a>

26 </p>

27 </div>

28 <!--end-logo-->

29

30 <h1>WebGL Specification</h1>

31 <h2 class="no-toc">Version 1.0, 10 February 2011</h2>

32 <dl>

33 <dt>This version:

34 <dd>

35 <a href="https://www.khronos.org/registry/webgl/specs/1.0/">

36 https://www.khronos.org/registry/webgl/specs/1.0/

37 </a>

38 <br>

39 <a href="https://www.khronos.org/registry/webgl/specs/1.0/webgl. idl">

40 <b>WebIDL:</b> https://www.khronos.org/registry/webgl/specs/ 1.0/webgl.idl

41 </a>

42 </dd>

43 <dt>Latest version:

44 <dd>

45 <a href="https://www.khronos.org/registry/webgl/specs/latest/">

46 https://www.khronos.org/registry/webgl/specs/latest/

47 </a>

48 <br>

49 <a href="https://www.khronos.org/registry/webgl/specs/latest/web gl.idl">

50 <b>WebIDL:</b> https://www.khronos.org/registry/webgl/specs/ latest/webgl.idl

51 </a>

52 </dd>

53 <dt>Previous version:

54 <dd>

55 none

56 </dd>

57 <dt>Editor:

58 <dd>

59 <a href="mailto:cmarrin@apple.com">Chris Marrin</a>

60 <a href="http://www.apple.com/">(Apple Inc.)</a>

61 </dd>

62 </dl>

63

64 <span style="font-size: x-small; font-style: oblique">Copyright © 2010, 2011 Khronos Group</span>

65

66 <hr />

67

68 <h2 class="no-toc">Abstract</h2>

69 <p>

70 This specification describes an additional rendering context and support

71 objects for the

72 <a href="http://www.w3.org/TR/html5/the-canvas-element.html"

73 title="HTML 5 Canvas Element">

74 HTML 5 <span class="prop-name">canvas</span> element <a href="#refsC ANVAS">[CANVAS]</a>.

75 </a>

76 This context allows rendering using an API that conforms closely to the OpenGL ES 2.0 API.

77 </p>

78

79 <h2 class="no-toc">Status of this document</h2>

80

81 <!--begin-status-->

82 <p>

83 Public discussion of this specification

84 is welcome on the (<a

85 href="https://www.khronos.org/webgl/public-mailing-list/archives/">a rchived</a>)

86 WebGL mailing list <a href="mailto:public_webgl@khronos.org">public_webg l@khronos.org</a> (see

87 <a href="http://www.khronos.org/webgl/public-mailing-list/">instructions </a>).

88 </p>

89 <!--end-status-->

90

91 <h2 class="no-toc">Table of contents</h2>

92 <div id="toc"></div>

93

94 <h2>Introduction</h2>

95 <div class="note">

96 <p>

97 WebGL™ is an immediate mode 3D rendering API designed for the

98 web. It is derived from OpenGL® ES 2.0, and provides similar

99 rendering functionality, but in an HTML context. WebGL is

100 designed as a rendering context for the HTML Canvas element.

101 The HTML Canvas provides a destination for programmatic

102 rendering in web pages, and allows for performing that rendering

103 using different rendering APIs. The only such interface

104 described as part of the Canvas specification is the 2D canvas

105 rendering context, CanvasRenderingContext2D. This document

106 describes another such interface, WebGLRenderingContext, which

107 presents the WebGL API.

108 </p>

109

110 <p>

111 The immediate mode nature of the API is a divergence from most

112 web APIs. Given the many use cases of 3D graphics, WebGL

113 chooses the approach of providing flexible primitives that can

114 be applied to any use case. Libraries can provide an API on top

115 of WebGL that is more tailored to specific areas, thus adding a

116 convenience layer to WebGL that can accelerate and simplify development.

117 However, because of its OpenGL ES 2.0 heritage, it should be

118 straightforward for developers familiar with modern desktop

119 OpenGL or OpenGL ES 2.0 development to transition to WebGL

120 development.

121 </p>

122

123 <p>

124 Many functions described in this document contain links to OpenGL ES

125 man pages. While every effort is made to make these pages match the

126 OpenGL ES 2.0 specification <a href="#refsGLES20">[GLES20]</a>,

127 they may contain errors. In the case of a contradiction, the OpenGL

128 ES 2.0 specification is the final authority.

129 </p>

130

131 <p>

132 The remaining sections of this document are intended to be read in conjunc tion

133 with the OpenGL ES 2.0 specification (2.0.24 at the time of this writing, available

134 from the <a href="http://www.khronos.org/registry/gles/">Khronos OpenGL ES API Registry</a>).

135 Unless otherwise specified, the behavior of each method is defined by the

136 OpenGL ES 2.0 specification. This specification may diverge from OpenGL E S 2.0

137 in order to ensure interoperability or security, often defining areas that

138 OpenGL ES 2.0 leaves implementation-defined. These differences are summar ized in the

139 <a href="#webgl_gl_differences">Differences Between WebGL and OpenGL ES 2. 0</a> section.

140 </p>

141 </div>

142

143 <!-- =========================================================================== ============================ -->

144

145 <h2>Context Creation and Drawing Buffer Presentation</h2>

146

147 <p>

148 Before using the WebGL API, the author must obtain a WebGLRenderingConte xt object

149 for a given HTMLCanvasElement as described below. This object is used to manage

150 OpenGL state and render to the drawing buffer, which must also be create d at the time of

151 context creation. The author may supply configuration options for this d rawing buffer, otherwise

152 default values shall be used as specified elsewhere in this document. Th is drawing buffer

153 is presented to the HTML page compositor immediately before an HTML page compositing operation,

154 but only if the drawing buffer has been modified since the last composit ing operation.

155 </p>

156

157 <!-- =========================================================================== ============================ -->

158

159 <h3>The <span class=prop-name><code>canvas</code></span> Element</h3>

160

161 <p>

162 A WebGLRenderingContext object shall be created by calling the <code>get Context()</code>

163 method of a given HTMLCanvasElement <a href="#refsCANVAS">[CANVAS]</a> o bject with the exact string

164 ‘<code class=property>webgl</code>’. This string is case se nsitive. When called

165 for the first time, a WebGLRenderingContext object is created and return ed. Also at this

166 time a drawing buffer shall be created. Subsequent calls to <code>getCon text()</code> with

167 the same string shall return the same object.

168 </p>

169 <p>

170 The HTML Canvas specification <a href="#refsCANVAS">[CANVAS]</a>

171 defines the behavior when attempting to fetch two or more

172 incompatible contexts against the same canvas element.

173 </p>

174 <p>

175 A second parameter may be passed to the <code>getContext()</code> method . If passed, this

176 parameter shall be a WebGLContextAttributes object containing configurat ion parameters to be

177 used in creating the drawing buffer.

178 See <a href="#WEBGLCONTEXTATTRIBUTES">WebGLContextAttributes</a> for mor e details.

179 </p>

180 <p>

181 The passed attributes are requests, not requirements. The WebGL implemen tation does not

182 guarantee that they will be obeyed, but should make a best effort to hon or them.

183 Combinations of attributes not supported by the WebGL implementation or graphics hardware

184 shall not cause a failure to create a WebGLRenderingContext. The attribu tes actually used to

185 create the context may be queried by the <code>getContextAttributes()</c ode> method on the

186 WebGLRenderingContext.

187 </p>

188 <p>

189 On subsequent calls to getContext() with the ‘<code class=property >webgl</code>’

190 string, the passed WebGLContextAttributes object, if any, shall be ignor ed.

191 <p>

192 </p>

193

194 <!-- =========================================================================== ============================ -->

195

196 <h3><a name="THE_DRAWING_BUFFER">The Drawing Buffer</a></h3>

197

198 <p>

199 The drawing buffer into which the API calls are rendered shall be define d upon creation of

200 the WebGLRenderingContext object. The table below shows all the buffers which make up

201 the drawing buffer, along with their minimum sizes and whether they are defined or not by

202 default. The size of this drawing buffer shall be determined by the <cod e>width</code>

203 and <code>height</code> attributes of the HTMLCanvasElement. The table b elow also shows

204 the value to which these buffers shall be cleared when first created or when the size is

205 changed.

206 </p>

207 <table class="foo">

208 <tr><th>Buffer</th><th>Clear value</th><th>Minimum size</th><th>Defined by default?</th></tr>

209 <tr><td>Color</td><td>(0, 0, 0, 0)</td><td>8 bits per component</td><td> yes</td></tr>

210 <tr><td>Depth</td><td>1.0</td><td>16 bit integer</td><td>yes</td></tr>

211 <tr><td>Stencil</td><td>0</td><td>8 bits</td><td>no</td></tr>

212 </table>

213 <br>

214 <p>

215 If the requested width or height cannot be satisfied, either when the dr awing buffer is first

216 created or when the <code>width</code> and <code>height</code> attribute s of the

217 <code>HTMLCanvasElement</code> are changed, a drawing buffer with smalle r dimensions shall

218 be created. The dimensions actually used are implementation dependent an d there is no

219 guarantee that a buffer with the same aspect ratio will be created. The actual drawing

220 buffer size can be obtained from the <code>drawingBufferWidth</code> and

221 <code>drawingBufferHeight</code> attributes.

222 </p>

223 <p>

224 By default, the buffers shall be the size shown below. The optional <a h ref="#WEBGLCONTEXTATTRIBUTES">WebGLContextAttributes</a>

225 object may be used to change whether or not the buffers are defined. It can also be used

226 to define whether the color buffer will include an alpha channel. If def ined, the

227 alpha channel is used by the HTML compositor to combine the color buffer with the rest

228 of the page. The WebGLContextAttributes object is only used on the first call to

229 <code>getContext</code>. No facility is provided to change the attribute s of the drawing

230 buffer after its creation.

231 </p>

232 <p>

233 WebGL presents its drawing buffer to the HTML page compositor immediatel y before a compositing

234 operation, but only if the drawing buffer has been modified since the la st compositing operation.

235 Before the drawing buffer is presented for compositing the implementatio n shall ensure that all

236 rendering operations have been flushed to the drawing buffer. By default , after compositing the

237 contents of the drawing buffer shall be cleared to their default values, as shown in the table

238 above.

239 </p>

240 <p>

241 This default behavior can be changed by setting the <code>preserveDrawin gBuffer</code>

242 attribute of the <a href="#WEBGLCONTEXTATTRIBUTES">WebGLContextAttribute s</a> object. If

243 this flag is true, the contents of the drawing buffer shall be preserved until the author

244 either clears or overwrites them. If this flag is false, attempting to p erform operations

245 using this context as a source image after the rendering function has re turned can lead to

246 undefined behavior. This includes <code>readPixels</code> or <code>toDat aURL</code> calls,

247 or using this context as the source image of another context's <code>tex Image2D</code> or

248 <code>drawImage</code> call.

249 </p>

250 <div class="note">

251 <p>

252 While it is sometimes desirable to preserve the drawing buffer, it c an cause significant

253 performance loss on some platforms. Whenever possible this flag shou ld remain false

254 and other techniques used. Techniques like synchronous drawing buffe r access (e.g.,

255 calling <code>readPixels</code> or <code>toDataURL</code> in the sam e function that

256 renders to the drawing buffer) can be used to get the contents of th e drawing buffer.

257 If the author needs to render to the same drawing buffer over a seri es of calls, a

258 <a href="#WEBGL_FRAMEBUFFER">Framebuffer Object</a> can be used.

259 </p>

260 <p>

261 Implementations may optimize away the required implicit clear operat ion of the Drawing

262 Buffer as long as a guarantee can be made that the author cannot gai n access to buffer

263 contents from another process. For instance, if the author performs an explicit

264 clear then the implicit clear is not needed.

265 </p>

266 </div>

267

268 <!-- =========================================================================== ============================ -->

269

270 <h3>The WebGL Viewport</h3>

271

272 <p>

273 OpenGL manages a rectangular viewport as part of its state which defines the placement of the

274 rendering results in the drawing buffer. Upon creation of the WebGL cont ext, the viewport is

275 initialized to a rectangle with origin at (0, 0) and width and height eq ual to (canvas.width,

276 canvas.height).

277 </p>

278 <p>

279 A WebGL implementation <em>shall not</em> affect the state of the OpenGL viewport in response to

280 resizing of the canvas element.

281 </p>

282 <div class="example">

283 Note that if a WebGL program does not contain logic to set the viewport, it will not properly

284 handle the case where the canvas is resized. The following ECMAScript ex ample illustrates how

285 a WebGL program might resize the canvas programmatically.

286

287 <pre>

288 var canvas = document.getElementById('canvas1');

289 var gl = canvas.getContext('webgl');

290 canvas.width = newWidth;

291 canvas.height = newHeight;

292 gl.viewport(0, 0, canvas.width, canvas.height);

293 </pre>

294 </div>

295 <p>

296 <em>Rationale</em>: automatically setting the viewport will interfere wi th applications that set

297 it manually. Applications are expected to use <code>onresize</code> hand lers to respond to

298 changes in size of the canvas and set the OpenGL viewport in turn.

299 </p>

300

301 <!-- =========================================================================== ============================ -->

302

303 <h3><a name="PREMULTIPLIED_ALPHA">Premultiplied Alpha, Canvas APIs and texIm age2D</a></h3>

304

305 <p>

306 The OpenGL API allows the application to modify the blending modes used during rendering,

307 and for this reason allows control over how alpha values in the drawing buffer are

308 interpreted; see the <code>premultipliedAlpha</code> parameter in

309 the <a href="#WEBGLCONTEXTATTRIBUTES">WebGLContextAttributes</a> section .

310 </p>

311 <p>

312 The HTML Canvas APIs <code>toDataURL</code> and <code>drawImage</code> m ust respect

313 the <code>premultipliedAlpha</code> context creation parameter. When <co de>toDataURL</code>

314 is called against a Canvas into which WebGL content is being rendered, t hen if the requested

315 image format does not specify premultiplied alpha and the WebGL context has

316 the <code>premultipliedAlpha</code> parameter set to true, then the pixe l values must be

317 de-multiplied; i.e., the color channels are divided by the alpha channel . <b>Note</b> that

318 this operation is lossy.

319 </p>

320 <p>

321 Passing a WebGL-rendered Canvas to the <code>drawImage</code> method

322 of <code>CanvasRenderingContext2D</code> may or may not need to modify t he the rendered

323 WebGL content during the drawing operation, depending on the premultipli cation needs of the

324 <code>CanvasRenderingContext2D</code> implementation.

325 </p>

326 <p>

327 When passing a WebGL-rendered Canvas to the <code>texImage2D</code> API, then depending on

328 the setting of the <code>premultipliedAlpha</code> context creation para meter of the passed

329 canvas and the <code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code> pixel store p arameter of the

330 destination WebGL context, the pixel data may need to be changed to or f rom premultiplied

331 form.

332 </p>

333

334 <!-- =========================================================================== ============================ -->

335

336 <h2>WebGL Resources</h2>

337

338 <p>

339 OpenGL manages several types of resources as part of its state. These ar e identified

340 by integer object names and are obtained from OpenGL by various creation calls.

341 In contrast WebGL represents these resources as DOM objects. Each object is derived

342 from the WebGLObject interface. Currently supported resources are:

343 textures, buffers (i.e., VBOs), framebuffers, renderbuffers, shaders and

344 programs. The WebGLRenderingContext interface has a method to create a

345 WebGLObject subclass for each type. Data from the underlying graphics li brary are

346 stored in these objects and are fully managed by them. The resources rep resented

347 by these objects are guaranteed to exist as long as the object exists.

348 Furthermore, the DOM object is guaranteed to exist as long as the author has an explicit

349 valid reference to it <b>or</b> as long as it is bound by the underlying graphics library.

350 When none of these conditions exist the user agent can, at any point, de lete the object

351 using the equivalent of a delete call (e.g., deleteTexture). If authors wish to control

352 when the underlying resource is released then the delete call can be mad e explicitly.

353 </p>

354

355 <!-- =========================================================================== ============================ -->

356

357 <h2>Security</h2>

358

359 <p>

360 </p>

361

362 <!-- =========================================================================== ============================ -->

363

364 <h3>Resource Restrictions</h3>

365

366 <p>

367 WebGL resources such as textures and vertex buffer objects (VBOs) must a lways

368 contain initialized data, even if they were created without initial user

369 data values. Creating a resource without initial values is commonly use d to

370 reserve space for a texture or VBO, which is then modified using <code>t exSubImage</code> or

371 <code>bufferSubData</code> calls. If initial data is not provided to th ese calls, the WebGL

372 implementation must initialize their contents to 0; depth renderbuffers must be cleared to

373 the default 1.0 clear depth. For example, this may require creating a t emporary buffer of 0

374 values the size of a requested VBO, so that it can be initialized correc tly. All other

375 forms of loading data into a texture or VBO involve either ArrayBuffers or DOM objects such

376 as images, and are therefore already required to be initialized.

377 </p>

378

379 <p>

380 When WebGL resources are accessed by shaders through a call such as

381 <code>drawElements</code> or <code>drawArrays</code>, the WebGL implemen tation must ensure

382 that the shader cannot access either out of bounds or uninitialized data .

383 See <a href="#ATTRIBS_AND_RANGE_CHECKING">Enabled Vertex Attributes and Range Checking</a>

384 for restrictions which must be enforced by the WebGL implementation.

385 </p>

386

387 <!-- =========================================================================== ============================ -->

388

389 <h3>Origin Restrictions</h3>

390

391 <p>

392 In order to prevent information leakage, the HTML5 canvas element has

393 a <i>origin-clean</i> flag. (See HTML5, section 4.8.11.3, "Security wit h canvas

394 elements".) For a WebGL context, the <i>origin-clean</i> flag must be s et to false

395 if any of the following actions occur:

396 </p>

397 <ul>

398 <li>The <code>texImage2D</code> method is called with an <code>HTMLI mageElement</code> or

399 <code>HTMLVideoElement</code> whose origin is not the same as th at of the Document

400 object that owns the canvas element.

401 <li>The <code>texImage2D</code> method is called with an <code>HTMLC anvasElement</code>

402 whose <i>origin-clean</i> flag is set to false.

403 </ul>

404 <p>

405 Whenever the <code>readPixels</code> method of the 2D context of a <code >canvas</code>

406 element whose <i>origin-clean</i> flag is set to false is called with ot herwise correct

407 arguments, the method must raise a <code>SECURITY_ERR</code> exception.

408 </p>

409

410 <!-- =========================================================================== ============================ -->

411

412 <h3><a name="SUPPORTED_GLSL_CONSTRUCTS">Supported GLSL Constructs</a></h3>

413

414 <p>

415 A WebGL implementation must only accept shaders which conform to The Ope nGL ES Shading

416 Language, Version 1.00 <a href="#refsGLES20GLSL">[GLES20GLSL]</a>, and w hich do not exceed

417 the minimum functionality mandated in Sections 4 and 5 of Appendix A. I n particular, a shader

418 referencing state variables or functions that are available in other ver sions of GLSL (such

419 as that found in versions of OpenGL for the desktop), must not be allowe d to load.

420 </p>

421 <p>

422 In addition to the reserved identifiers in the aforementioned specificat ion, identifiers

423 starting with "webgl_" and "_webgl_" are reserved for use by WebGL. A sh ader which declares

424 a function, variable, structure name, or structure field starting with t hese prefixes must

425 not be allowed to load.

426 </p>

427

428 <!-- =========================================================================== ============================ -->

429

430 <h3>Defense Against Denial of Service</h3>

431 <div class="note">

432 <p>

433 It is possible to create, either intentionally or unintentionally, combinati ons of shaders and

434 geometry that take an undesirably long time to render. This issue is analogo us to that of

435 long-running scripts, for which user agents already have safeguards. However , long-running draw

436 calls can cause loss of interactivity for the entire window system, not just the user agent.

437 </p>

438

439 <p>

440 In the general case it is not possible to impose limits on the structure of incoming shaders to

441 guard against this problem. Experimentation has shown that even very strict structural limits

442 are insufficient to prevent long rendering times, and such limits would prev ent shader authors

443 from implementing common algorithms.

444 </p>

445

446 <p>

447 User agents should implement safeguards to prevent excessively long renderin g times and

448 associated loss of interactivity. Suggested safeguards include:

449 </p>

450

451 <ul>

452

453 <li> Splitting up draw calls with large numbers of elements into smaller dra w calls.

454

455 <li> Timing individual draw calls and forbidding further rendering from a pa ge if a certain

456 timeout is exceeded.

457

458 <li> Using any watchdog facilities available at the user level, graphics API level, or operating

459 system level to limit the duration of draw calls.

460

461 <li> Separating the graphics rendering of the user agent into a distinct ope rating system

462 process which can be terminated and restarted without losing applicatio n state.

463

464 </ul>

465

466 <p>

467 The supporting infrastructure at the OS and graphics API layer is expected t o improve over time,

468 which is why the exact nature of these safeguards is not specified.

469 </p>

470 </div>

471 <!-- =========================================================================== ============================ -->

472

473 <h2>DOM Interfaces</h2>

474

475 <p>

476 This section describes the interfaces and functionality added to the

477 DOM to support runtime access to the functionality described above.

478 </p>

479

480 <!-- =========================================================================== ============================ -->

481

482 <h3>Types</h3>

483

484 <p>

485 The following types are used in all interfaces in the following section.

486 </p>

487 <pre class="idl">

488 typedef events::Event Event;

489 typedef html::HTMLCanvasElement HTMLCanvasElement;

490 typedef html::HTMLImageElement HTMLImageElement;

491 typedef html::HTMLVideoElement HTMLVideoElement;

492 typedef html::ImageData ImageData;

493

494 typedef unsigned long GLenum;

495 typedef boolean GLboolean;

496 typedef unsigned long GLbitfield;

497 typedef byte GLbyte; /* 'byte' should be a signed 8 bit type. */

498 typedef short GLshort;

499 typedef long GLint;

500 typedef long GLsizei;

501 typedef long long GLintptr;

502 typedef long long GLsizeiptr;

503 typedef unsigned byte GLubyte; /* 'unsigned byte' should be an unsigned 8 bit type. */

504 typedef unsigned short GLushort;

505 typedef unsigned long GLuint;

506 typedef float GLfloat;

507 typedef float GLclampf;

508 </pre>

509

510 <!-- =========================================================================== ============================ -->

511

512 <h3><a name="WEBGLCONTEXTATTRIBUTES">WebGLContextAttributes</a></h3>

513

514 <p>

515 The <code>WebGLContextAttributes</code> interface contains drawing surfa ce attributes and is

516 passed as the second parameter to <code>getContext</code>. A native obje ct may be supplied

517 as this parameter; the specified attributes will be queried from this ob ject.

518 </p>

519 <pre class="idl">[Callback] interface <dfn id="WebGLContextAttributes">WebGL ContextAttributes</dfn> {

520 attribute boolean alpha;

521 attribute boolean depth;

522 attribute boolean stencil;

523 attribute boolean antialias;

524 attribute boolean premultipliedAlpha;

525 attribute boolean preserveDrawingBuffer;

526 };</pre>

527

528 <h4>Context creation parameters</h4>

529

530 <p>

531 The following list describes each attribute in the WebGLContextAttribute s object and its

532 use. For each attribute the default value is shown. The default value is used either if no

533 second parameter is passed to <code>getContext</code>, or if a native ob ject is passed which

534 has no attribute of the given name.

535 </p>

536 <dl>

537 <dt><span class=prop-value>alpha</span></dt>

538 <dd>

539 <em>Default: true</em>. If the value is true, the drawing buffer has an alpha

540 channel for the purposes of performing OpenGL destination alpha operations and

541 compositing with the page. If the value is false, no alpha buffe r is available.

542 </dd>

543 <dt> <span class=prop-value>depth</span>

544 <dd>

545 <em>Default: true</em>. If the value is true, the drawing buffer has a depth

546 buffer of at least 16 bits. If the value is false, no depth buff er is

547 available.

548 </dd>

549 <dt> <span class=prop-value>stencil</span>

550 <dd>

551 <em>Default: false</em>. If the value is true, the drawing buffe r has a stencil

552 buffer of at least 8 bits. If the value is false, no stencil buf fer is

553 available.

554 </dd>

555 <dt> <span class=prop-value>antialias</span>

556 <dd>

557 <em>Default: true</em>. If the value is true and the implementat ion supports

558 antialiasing the drawing buffer will perform antialiasing using its choice of

559 technique (multisample/supersample) and quality. If the value is false or the

560 implementation does not support antialiasing, no antialiasing is performed.

561 </dd>

562 <dt> <span class=prop-value>premultipliedAlpha</span>

563 <dd>

564 <em>Default: true</em>. If the value is true the page compositor will assume the

565 drawing buffer contains colors with premultiplied alpha. If the value is false the

566 page compositor will assume that colors in the drawing buffer ar e not

567 premultiplied. This flag is ignored if the <strong>alpha</strong > flag is

568 false. See <a href="#PREMULTIPLIED_ALPHA">Premultiplied Alpha</a > for more

569 information on the effects of the <code>premultipliedAlpha</code > flag.

570 </dd>

571 <dt> <span class=prop-value>preserveDrawingBuffer</span>

572 <dd>

573 <em>Default: false</em>. If false, once the drawing buffer is pr esented

574 as described in the<a href="#THE_DRAWING_BUFFER">Drawing Buffer< /a> section,

575 the contents of the drawing buffer are cleared to their default values.

576 All elements of the drawing buffer (color, depth and stencil) ar e cleared.

577 If the value is true the buffers will not be cleared and will pr eserve

578 their values until cleared or overwritten by the author.

579 <blockquote>

580 <em>

581 On some hardware setting the <code>preserveDrawingBuffer</co de> flag

582 to true can have significant performance implications.

583 </em>

584 </blockquote>

585 </dd>

586 </dl>

587 <div class="example">

588 Here is an ECMAScript example which passes a WebGLContextAttributes argument

589 to <code>getContext</code>. It assumes the presence of a canvas element nam ed "canvas1" on the

590 page.

591

592 <pre>

593 var canvas = document.getElementById('canvas1');

594 var context = canvas.getContext('webgl',

595 { antialias: false,

596 stencil: true });

597 </pre>

598 </div>

599

600 <!-- =========================================================================== ============================ -->

601

602 <h3>WebGLObject</h3>

603

604 <p>

605 The <code>WebGLObject</code> interface is the parent interface for all G L objects.

606 </p>

607 <pre class="idl">interface <dfn id="WebGLObject">WebGLObject</dfn> {

608 };</pre>

609

610 <!-- =========================================================================== ============================ -->

611

612 <h3>WebGLBuffer</h3>

613

614 <p>

615 The <code>WebGLBuffer</code> interface represents an OpenGL Buffer Objec t. The

616 underlying object is created as if by calling glGenBuffers

617 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2.9</a >, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/docs/ma n/glGenBuffers.xml">man page</a>)</span>

618 , bound as if by calling glBindBuffer

619 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2.9</a >, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/docs/ma n/glBindBuffer.xml">man page</a>)</span>

620 and destroyed as if by calling glDeleteBuffers

621 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2.9</a >, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/docs/ma n/glDeleteBuffers.xml">man page</a>)</span>

622 .

623 </p>

624 <pre class="idl">interface <dfn id="WebGLBuffer">WebGLBuffer</dfn> : WebGLOb ject {

625 };</pre>

626

627 <!-- =========================================================================== ============================ -->

628

629 <h3><a name="WEBGL_FRAMEBUFFER">WebGLFramebuffer</a></h3>

630

631 <p>

632 The <code>WebGLFramebuffer</code> interface represents an OpenGL Framebu ffer Object. The

633 underlying object is created as if by calling glGenFramebuffers

634 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.1">OpenGL ES 2.0 §4.4. 1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glGenFramebuffers.xml">man page</a>)</span>

635 , bound as if by calling glBindFramebuffer

636 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.1">OpenGL ES 2.0 §4.4. 1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glBindFramebuffer.xml">man page</a>)</span>

637 and destroyed as if by calling glDeleteFramebuffers

638 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.1">OpenGL ES 2.0 §4.4. 1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glDeleteFramebuffers.xml">man page</a>)</span>

639 .

640 </p>

641 <pre class="idl">interface <dfn id="WebGLFramebuffer">WebGLFramebuffer</dfn> : WebGLObject {

642 };</pre>

643

644 <!-- =========================================================================== ============================ -->

645

646 <h3>WebGLProgram</h3>

647

648 <p>

649 The <code>WebGLProgram</code> interface represents an OpenGL Program Obj ect. The

650 underlying object is created as if by calling glCreateProgram

651 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 §2.1 0.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glCreateProgram.xml">man page</a>)</span>

652 , used as if by calling glUseProgram

653 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 §2.1 0.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glUseProgram.xml">man page</a>)</span>

654 and destroyed as if by calling glDeleteProgram

655 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 §2.1 0.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glDeleteProgram.xml">man page</a>)</span>

656 .

657 </p>

658 <pre class="idl">interface <dfn id="WebGLProgram">WebGLProgram</dfn> : WebGL Object {

659 };</pre>

660

661 <!-- =========================================================================== ============================ -->

662

663 <h3>WebGLRenderbuffer</h3>

664

665 <p>

666 The <code>WebGLRenderbuffer</code> interface represents an OpenGL Render buffer Object. The

667 underlying object is created as if by calling glGenRenderbuffers

668 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 §4.4. 3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glGenRenderbuffers.xml">man page</a>)</span>

669 , bound as if by calling glBindRenderbuffer

670 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 §4.4. 3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glBindRenderbuffer.xml">man page</a>)</span>

671 and destroyed as if by calling glDeleteRenderbuffers

672 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 §4.4. 3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glDeleteRenderbuffers.xml">man page</a>)</span>

673 .

674 </p>

675 <pre class="idl">interface <dfn id="WebGLRenderbuffer">WebGLRenderbuffer</df n> : WebGLObject {

676 };</pre>

677

678 <!-- =========================================================================== ============================ -->

679

680 <h3>WebGLShader</h3>

681

682 <p>

683 The <code>WebGLShader</code> interface represents an OpenGL Shader Objec t. The

684 underlying object is created as if by calling glCreateShader

685 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.1">OpenGL ES 2.0 §2.1 0.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glCreateShader.xml">man page</a>)</span>

686 , attached to a Program as if by calling glAttachShader

687 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 §2.1 0.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glAttachShader.xml">man page</a>)</span>

688 and destroyed as if by calling glDeleteShader

689 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.1">OpenGL ES 2.0 §2.1 0.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glDeleteShader.xml">man page</a>)</span>

690 .

691 </p>

692 <pre class="idl">interface <dfn id="WebGLShader">WebGLShader</dfn> : WebGLOb ject {

693 };</pre>

694

695 <!-- =========================================================================== ============================ -->

696

697 <h3>WebGLTexture</h3>

698

699 <p>

700 The <code>WebGLTexture</code> interface represents an OpenGL Texture Obj ect. The

701 underlying object is created as if by calling glGenTextures

702 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.13">OpenGL ES 2.0 §3.7 .13</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glGenTextures.xml">man page</a>)</span>

703 , bound as if by calling glBindTexture

704 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.13">OpenGL ES 2.0 §3.7 .13</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glBindTexture.xml">man page</a>)</span>

705 and destroyed as if by calling glDeleteTextures

706 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles/spe cs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.13">OpenGL ES 2.0 §3.7 .13</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/d ocs/man/glDeleteTextures.xml">man page</a>)</span>

707 .

708 </p>

709 <pre class="idl">interface <dfn id="WebGLTexture">WebGLTexture</dfn> : WebGL Object {

710 };</pre>

711

712 <!-- =========================================================================== ============================ -->

713

714 <h3>WebGLUniformLocation</h3>

715

716 <p>

717 The <code>WebGLUniformLocation</code> interface represents the location of a uniform variable

718 in a shader program.

719 </p>

720 <pre class="idl">interface <dfn id="WebGLUniformLocation">WebGLUniformLocati on</dfn> {

721 };</pre>

722

723 <!-- =========================================================================== ============================ -->

724

725 <h3>WebGLActiveInfo</h3>

726

727 <p>

728 The <code>WebGLActiveInfo</code> interface represents the information re turned

729 from the getActiveAttrib and getActiveUniform calls.

730 </p>

731 <pre class="idl">interface <dfn id="WebGLActiveInfo">WebGLActiveInfo</dfn> {

732 readonly attribute GLint size;

733 readonly attribute GLenum type;

734 readonly attribute DOMString name;

735 };</pre>

736

737 <h4>Attributes</h4>

738

739 <p>

740 The following attributes are available:

741 </p>

742

743 <dl class="methods">

744 <dt>

745 <code class=attribute-name>

746 <a id="DOM-WebGLActiveInfo-size">

747 size

748 </a>

749 </code>

750 of type <code>GLint</code>

751 <dd>

752 The size of the requested variable.

753 <dt>

754 <code class=attribute-name>

755 <a id="DOM-WebGLActiveInfo-type">

756 type

757 </a>

758 </code>

759 of type <code>GLenum</code>

760 <dd>

761 The data type of the requested variable.

762 <dt>

763 <code class=attribute-name>

764 <a id="DOM-WebGLActiveInfo-name">

765 name

766 </a>

767 </code>

768 of type <code>DOMString</code>

769 <dd>

770 The name of the requested variable.

771 </dl>

772

773 <!-- =========================================================================== ============================ -->

774

775 <h3><a name="ARRAYBUFFER">ArrayBuffer</a> and <a name="TYPEDARRAY">Typed Arr ays</a></h3>

776

777 <p>

778 Vertex, index, texture, and other data is transferred to the WebGL imple mentation using

779 the <a href="../../../typedarray/specs/1.0/#ARRAYBUFFER">ArrayBuffer</a>

780 and <a href="../../../typedarray/specs/1.0/#TYPEDARRAYS">views</a> defin ed in

781 the <a href="../../../typedarray/specs/1.0/">Typed Array</a>

782 specification <a href="#refsTYPEDARRAYS">[TYPEDARRAYS]</a>. All of the t yped array views

783 except <tt>Float64Array</tt> may be used in conjunction with WebGL; Open GL ES 2.0, and

784 therefore WebGL, does not support double-precision floating-point data.

785 </p>

786 <p>

787 Typed Arrays support the creation of interleaved, heterogeneous vertex d ata; uploading of

788 distinct blocks of data into a large vertex buffer object; and most othe r use cases required

789 by OpenGL programs.

790 </p>

791

792 <div class="example">

793 Here is an ECMAScript example showing access to the same ArrayBuffer using d ifferent types of

794 typed arrays. In this case the buffer contains a floating point vertex posit ion (x, y, z)

795 followed by a color as 4 unsigned bytes (r, g, b, a).

796

797 <pre>

798 var numVertices = 100; // for example

799

800 // Compute the size needed for the buffer, in bytes and floats

801 var vertexSize = 3 * Float32Array.BYTES_PER_ELEMENT +

802 4 * Uint8Array.BYTES_PER_ELEMENT;

803 var vertexSizeInFloats = vertexSize / Float32Array.BYTES_PER_ELEMENT;

804

805 // Allocate the buffer

806 var buf = new ArrayBuffer(numVertices * vertexSize);

807

808 // Map this buffer to a Float32Array to access the positions

809 var positionArray = new Float32Array(buf);

810

811 // Map the same buffer to a Uint8Array to access the color

812 var colorArray = new Uint8Array(buf);

813

814 // Set up the initial offset of the vertices and colors within the buffer

815 var positionIdx = 0;

816 var colorIdx = 3 * Float32Array.BYTES_PER_ELEMENT;

817

818 // Initialize the buffer

819 for (var i = 0; i < numVertices; i++) {

820 positionArray[positionIdx] = ...;

821 positionArray[positionIdx + 1] = ...;

822 positionArray[positionIdx + 2] = ...;

823 colorArray[colorIdx] = ...;

824 colorArray[colorIdx + 1] = ...;

825 colorArray[colorIdx + 2] = ...;

826 colorArray[colorIdx + 3] = ...;

827 positionIdx += vertexSizeInFloats;

828 colorIdx += vertexSize;

829 }

830 </pre>

831 </div>

832

833 <!-- =========================================================================== ============================ -->

834

835 <h3><a name="WEBGLRENDERINGCONTEXT">The WebGL context</a></h3>

836

837 <p>

838 The <code>WebGLRenderingContext</code> represents the API allowing

839 OpenGL ES 2.0 style rendering into the canvas element.

840 </p>

841 <pre class="idl">interface <dfn id="WebGLRenderingContext">WebGLRenderingCon text</dfn> {

842

843 /* ClearBufferMask */

844 const GLenum DEPTH_BUFFER_BIT = 0x00000100;

845 const GLenum STENCIL_BUFFER_BIT = 0x00000400;

846 const GLenum COLOR_BUFFER_BIT = 0x00004000;

847

848 /* BeginMode */

849 const GLenum POINTS = 0x0000;

850 const GLenum LINES = 0x0001;

851 const GLenum LINE_LOOP = 0x0002;

852 const GLenum LINE_STRIP = 0x0003;

853 const GLenum TRIANGLES = 0x0004;

854 const GLenum TRIANGLE_STRIP = 0x0005;

855 const GLenum TRIANGLE_FAN = 0x0006;

856

857 /* AlphaFunction (not supported in ES20) */

858 /* NEVER */

859 /* LESS */

860 /* EQUAL */

861 /* LEQUAL */

862 /* GREATER */

863 /* NOTEQUAL */

864 /* GEQUAL */

865 /* ALWAYS */

866

867 /* BlendingFactorDest */

868 const GLenum ZERO = 0;

869 const GLenum ONE = 1;

870 const GLenum SRC_COLOR = 0x0300;

871 const GLenum ONE_MINUS_SRC_COLOR = 0x0301;

872 const GLenum SRC_ALPHA = 0x0302;

873 const GLenum ONE_MINUS_SRC_ALPHA = 0x0303;

874 const GLenum DST_ALPHA = 0x0304;

875 const GLenum ONE_MINUS_DST_ALPHA = 0x0305;

876

877 /* BlendingFactorSrc */

878 /* ZERO */

879 /* ONE */

880 const GLenum DST_COLOR = 0x0306;

881 const GLenum ONE_MINUS_DST_COLOR = 0x0307;

882 const GLenum SRC_ALPHA_SATURATE = 0x0308;

883 /* SRC_ALPHA */

884 /* ONE_MINUS_SRC_ALPHA */

885 /* DST_ALPHA */

886 /* ONE_MINUS_DST_ALPHA */

887

888 /* BlendEquationSeparate */

889 const GLenum FUNC_ADD = 0x8006;

890 const GLenum BLEND_EQUATION = 0x8009;

891 const GLenum BLEND_EQUATION_RGB = 0x8009; /* same as BLEND_EQU ATION */

892 const GLenum BLEND_EQUATION_ALPHA = 0x883D;

893

894 /* BlendSubtract */

895 const GLenum FUNC_SUBTRACT = 0x800A;

896 const GLenum FUNC_REVERSE_SUBTRACT = 0x800B;

897

898 /* Separate Blend Functions */

899 const GLenum BLEND_DST_RGB = 0x80C8;

900 const GLenum BLEND_SRC_RGB = 0x80C9;

901 const GLenum BLEND_DST_ALPHA = 0x80CA;

902 const GLenum BLEND_SRC_ALPHA = 0x80CB;

903 const GLenum CONSTANT_COLOR = 0x8001;

904 const GLenum ONE_MINUS_CONSTANT_COLOR = 0x8002;

905 const GLenum CONSTANT_ALPHA = 0x8003;

906 const GLenum ONE_MINUS_CONSTANT_ALPHA = 0x8004;

907 const GLenum BLEND_COLOR = 0x8005;

908

909 /* Buffer Objects */

910 const GLenum ARRAY_BUFFER = 0x8892;

911 const GLenum ELEMENT_ARRAY_BUFFER = 0x8893;

912 const GLenum ARRAY_BUFFER_BINDING = 0x8894;

913 const GLenum ELEMENT_ARRAY_BUFFER_BINDING = 0x8895;

914

915 const GLenum STREAM_DRAW = 0x88E0;

916 const GLenum STATIC_DRAW = 0x88E4;

917 const GLenum DYNAMIC_DRAW = 0x88E8;

918

919 const GLenum BUFFER_SIZE = 0x8764;

920 const GLenum BUFFER_USAGE = 0x8765;

921

922 const GLenum CURRENT_VERTEX_ATTRIB = 0x8626;

923

924 /* CullFaceMode */

925 const GLenum FRONT = 0x0404;

926 const GLenum BACK = 0x0405;

927 const GLenum FRONT_AND_BACK = 0x0408;

928

929 /* DepthFunction */

930 /* NEVER */

931 /* LESS */

932 /* EQUAL */

933 /* LEQUAL */

934 /* GREATER */

935 /* NOTEQUAL */

936 /* GEQUAL */

937 /* ALWAYS */

938

939 /* EnableCap */

940 /* TEXTURE_2D */

941 const GLenum CULL_FACE = 0x0B44;

942 const GLenum BLEND = 0x0BE2;

943 const GLenum DITHER = 0x0BD0;

944 const GLenum STENCIL_TEST = 0x0B90;

945 const GLenum DEPTH_TEST = 0x0B71;

946 const GLenum SCISSOR_TEST = 0x0C11;

947 const GLenum POLYGON_OFFSET_FILL = 0x8037;

948 const GLenum SAMPLE_ALPHA_TO_COVERAGE = 0x809E;

949 const GLenum SAMPLE_COVERAGE = 0x80A0;

950

951 /* ErrorCode */

952 const GLenum NO_ERROR = 0;

953 const GLenum INVALID_ENUM = 0x0500;

954 const GLenum INVALID_VALUE = 0x0501;

955 const GLenum INVALID_OPERATION = 0x0502;

956 const GLenum OUT_OF_MEMORY = 0x0505;

957

958 /* FrontFaceDirection */

959 const GLenum CW = 0x0900;

960 const GLenum CCW = 0x0901;

961

962 /* GetPName */

963 const GLenum LINE_WIDTH = 0x0B21;

964 const GLenum ALIASED_POINT_SIZE_RANGE = 0x846D;

965 const GLenum ALIASED_LINE_WIDTH_RANGE = 0x846E;

966 const GLenum CULL_FACE_MODE = 0x0B45;

967 const GLenum FRONT_FACE = 0x0B46;

968 const GLenum DEPTH_RANGE = 0x0B70;

969 const GLenum DEPTH_WRITEMASK = 0x0B72;

970 const GLenum DEPTH_CLEAR_VALUE = 0x0B73;

971 const GLenum DEPTH_FUNC = 0x0B74;

972 const GLenum STENCIL_CLEAR_VALUE = 0x0B91;

973 const GLenum STENCIL_FUNC = 0x0B92;

974 const GLenum STENCIL_FAIL = 0x0B94;

975 const GLenum STENCIL_PASS_DEPTH_FAIL = 0x0B95;

976 const GLenum STENCIL_PASS_DEPTH_PASS = 0x0B96;

977 const GLenum STENCIL_REF = 0x0B97;

978 const GLenum STENCIL_VALUE_MASK = 0x0B93;

979 const GLenum STENCIL_WRITEMASK = 0x0B98;

980 const GLenum STENCIL_BACK_FUNC = 0x8800;

981 const GLenum STENCIL_BACK_FAIL = 0x8801;

982 const GLenum STENCIL_BACK_PASS_DEPTH_FAIL = 0x8802;

983 const GLenum STENCIL_BACK_PASS_DEPTH_PASS = 0x8803;

984 const GLenum STENCIL_BACK_REF = 0x8CA3;

985 const GLenum STENCIL_BACK_VALUE_MASK = 0x8CA4;

986 const GLenum STENCIL_BACK_WRITEMASK = 0x8CA5;

987 const GLenum VIEWPORT = 0x0BA2;

988 const GLenum SCISSOR_BOX = 0x0C10;

989 /* SCISSOR_TEST */

990 const GLenum COLOR_CLEAR_VALUE = 0x0C22;

991 const GLenum COLOR_WRITEMASK = 0x0C23;

992 const GLenum UNPACK_ALIGNMENT = 0x0CF5;

993 const GLenum PACK_ALIGNMENT = 0x0D05;

994 const GLenum MAX_TEXTURE_SIZE = 0x0D33;

995 const GLenum MAX_VIEWPORT_DIMS = 0x0D3A;

996 const GLenum SUBPIXEL_BITS = 0x0D50;

997 const GLenum RED_BITS = 0x0D52;

998 const GLenum GREEN_BITS = 0x0D53;

999 const GLenum BLUE_BITS = 0x0D54;

1000 const GLenum ALPHA_BITS = 0x0D55;

1001 const GLenum DEPTH_BITS = 0x0D56;

1002 const GLenum STENCIL_BITS = 0x0D57;

1003 const GLenum POLYGON_OFFSET_UNITS = 0x2A00;

1004 /* POLYGON_OFFSET_FILL */

1005 const GLenum POLYGON_OFFSET_FACTOR = 0x8038;

1006 const GLenum TEXTURE_BINDING_2D = 0x8069;

1007 const GLenum SAMPLE_BUFFERS = 0x80A8;

1008 const GLenum SAMPLES = 0x80A9;

1009 const GLenum SAMPLE_COVERAGE_VALUE = 0x80AA;

1010 const GLenum SAMPLE_COVERAGE_INVERT = 0x80AB;

1011

1012 /* GetTextureParameter */

1013 /* TEXTURE_MAG_FILTER */

1014 /* TEXTURE_MIN_FILTER */

1015 /* TEXTURE_WRAP_S */

1016 /* TEXTURE_WRAP_T */

1017

1018 const GLenum NUM_COMPRESSED_TEXTURE_FORMATS = 0x86A2;

1019 const GLenum COMPRESSED_TEXTURE_FORMATS = 0x86A3;

1020

1021 /* HintMode */

1022 const GLenum DONT_CARE = 0x1100;

1023 const GLenum FASTEST = 0x1101;

1024 const GLenum NICEST = 0x1102;

1025

1026 /* HintTarget */

1027 const GLenum GENERATE_MIPMAP_HINT = 0x8192;

1028

1029 /* DataType */

1030 const GLenum BYTE = 0x1400;

1031 const GLenum UNSIGNED_BYTE = 0x1401;

1032 const GLenum SHORT = 0x1402;

1033 const GLenum UNSIGNED_SHORT = 0x1403;

1034 const GLenum INT = 0x1404;

1035 const GLenum UNSIGNED_INT = 0x1405;

1036 const GLenum FLOAT = 0x1406;

1037

1038 /* PixelFormat */

1039 const GLenum DEPTH_COMPONENT = 0x1902;

1040 const GLenum ALPHA = 0x1906;

1041 const GLenum RGB = 0x1907;

1042 const GLenum RGBA = 0x1908;

1043 const GLenum LUMINANCE = 0x1909;

1044 const GLenum LUMINANCE_ALPHA = 0x190A;

1045

1046 /* PixelType */

1047 /* UNSIGNED_BYTE */

1048 const GLenum UNSIGNED_SHORT_4_4_4_4 = 0x8033;

1049 const GLenum UNSIGNED_SHORT_5_5_5_1 = 0x8034;

1050 const GLenum UNSIGNED_SHORT_5_6_5 = 0x8363;

1051

1052 /* Shaders */

1053 const GLenum FRAGMENT_SHADER = 0x8B30;

1054 const GLenum VERTEX_SHADER = 0x8B31;

1055 const GLenum MAX_VERTEX_ATTRIBS = 0x8869;

1056 const GLenum MAX_VERTEX_UNIFORM_VECTORS = 0x8DFB;

1057 const GLenum MAX_VARYING_VECTORS = 0x8DFC;

1058 const GLenum MAX_COMBINED_TEXTURE_IMAGE_UNITS = 0x8B4D;

1059 const GLenum MAX_VERTEX_TEXTURE_IMAGE_UNITS = 0x8B4C;

1060 const GLenum MAX_TEXTURE_IMAGE_UNITS = 0x8872;

1061 const GLenum MAX_FRAGMENT_UNIFORM_VECTORS = 0x8DFD;

1062 const GLenum SHADER_TYPE = 0x8B4F;

1063 const GLenum DELETE_STATUS = 0x8B80;

1064 const GLenum LINK_STATUS = 0x8B82;

1065 const GLenum VALIDATE_STATUS = 0x8B83;

1066 const GLenum ATTACHED_SHADERS = 0x8B85;

1067 const GLenum ACTIVE_UNIFORMS = 0x8B86;

1068 const GLenum ACTIVE_ATTRIBUTES = 0x8B89;

1069 const GLenum SHADING_LANGUAGE_VERSION = 0x8B8C;

1070 const GLenum CURRENT_PROGRAM = 0x8B8D;

1071

1072 /* StencilFunction */

1073 const GLenum NEVER = 0x0200;

1074 const GLenum LESS = 0x0201;

1075 const GLenum EQUAL = 0x0202;

1076 const GLenum LEQUAL = 0x0203;

1077 const GLenum GREATER = 0x0204;

1078 const GLenum NOTEQUAL = 0x0205;

1079 const GLenum GEQUAL = 0x0206;

1080 const GLenum ALWAYS = 0x0207;

1081

1082 /* StencilOp */

1083 /* ZERO */

1084 const GLenum KEEP = 0x1E00;

1085 const GLenum REPLACE = 0x1E01;

1086 const GLenum INCR = 0x1E02;

1087 const GLenum DECR = 0x1E03;

1088 const GLenum INVERT = 0x150A;

1089 const GLenum INCR_WRAP = 0x8507;

1090 const GLenum DECR_WRAP = 0x8508;

1091

1092 /* StringName */

1093 const GLenum VENDOR = 0x1F00;

1094 const GLenum RENDERER = 0x1F01;

1095 const GLenum VERSION = 0x1F02;

1096

1097 /* TextureMagFilter */

1098 const GLenum NEAREST = 0x2600;

1099 const GLenum LINEAR = 0x2601;

1100

1101 /* TextureMinFilter */

1102 /* NEAREST */

1103 /* LINEAR */

1104 const GLenum NEAREST_MIPMAP_NEAREST = 0x2700;

1105 const GLenum LINEAR_MIPMAP_NEAREST = 0x2701;

1106 const GLenum NEAREST_MIPMAP_LINEAR = 0x2702;

1107 const GLenum LINEAR_MIPMAP_LINEAR = 0x2703;

1108

1109 /* TextureParameterName */

1110 const GLenum TEXTURE_MAG_FILTER = 0x2800;

1111 const GLenum TEXTURE_MIN_FILTER = 0x2801;

1112 const GLenum TEXTURE_WRAP_S = 0x2802;

1113 const GLenum TEXTURE_WRAP_T = 0x2803;

1114

1115 /* TextureTarget */

1116 const GLenum TEXTURE_2D = 0x0DE1;

1117 const GLenum TEXTURE = 0x1702;

1118

1119 const GLenum TEXTURE_CUBE_MAP = 0x8513;

1120 const GLenum TEXTURE_BINDING_CUBE_MAP = 0x8514;

1121 const GLenum TEXTURE_CUBE_MAP_POSITIVE_X = 0x8515;

1122 const GLenum TEXTURE_CUBE_MAP_NEGATIVE_X = 0x8516;

1123 const GLenum TEXTURE_CUBE_MAP_POSITIVE_Y = 0x8517;

1124 const GLenum TEXTURE_CUBE_MAP_NEGATIVE_Y = 0x8518;

1125 const GLenum TEXTURE_CUBE_MAP_POSITIVE_Z = 0x8519;

1126 const GLenum TEXTURE_CUBE_MAP_NEGATIVE_Z = 0x851A;

1127 const GLenum MAX_CUBE_MAP_TEXTURE_SIZE = 0x851C;

1128

1129 /* TextureUnit */

1130 const GLenum TEXTURE0 = 0x84C0;

1131 const GLenum TEXTURE1 = 0x84C1;

1132 const GLenum TEXTURE2 = 0x84C2;

1133 const GLenum TEXTURE3 = 0x84C3;

1134 const GLenum TEXTURE4 = 0x84C4;

1135 const GLenum TEXTURE5 = 0x84C5;

1136 const GLenum TEXTURE6 = 0x84C6;

1137 const GLenum TEXTURE7 = 0x84C7;

1138 const GLenum TEXTURE8 = 0x84C8;

1139 const GLenum TEXTURE9 = 0x84C9;

1140 const GLenum TEXTURE10 = 0x84CA;

1141 const GLenum TEXTURE11 = 0x84CB;

1142 const GLenum TEXTURE12 = 0x84CC;

1143 const GLenum TEXTURE13 = 0x84CD;

1144 const GLenum TEXTURE14 = 0x84CE;

1145 const GLenum TEXTURE15 = 0x84CF;

1146 const GLenum TEXTURE16 = 0x84D0;

1147 const GLenum TEXTURE17 = 0x84D1;

1148 const GLenum TEXTURE18 = 0x84D2;

1149 const GLenum TEXTURE19 = 0x84D3;

1150 const GLenum TEXTURE20 = 0x84D4;

1151 const GLenum TEXTURE21 = 0x84D5;

1152 const GLenum TEXTURE22 = 0x84D6;

1153 const GLenum TEXTURE23 = 0x84D7;

1154 const GLenum TEXTURE24 = 0x84D8;

1155 const GLenum TEXTURE25 = 0x84D9;

1156 const GLenum TEXTURE26 = 0x84DA;

1157 const GLenum TEXTURE27 = 0x84DB;

1158 const GLenum TEXTURE28 = 0x84DC;

1159 const GLenum TEXTURE29 = 0x84DD;

1160 const GLenum TEXTURE30 = 0x84DE;

1161 const GLenum TEXTURE31 = 0x84DF;

1162 const GLenum ACTIVE_TEXTURE = 0x84E0;

1163

1164 /* TextureWrapMode */

1165 const GLenum REPEAT = 0x2901;

1166 const GLenum CLAMP_TO_EDGE = 0x812F;

1167 const GLenum MIRRORED_REPEAT = 0x8370;

1168

1169 /* Uniform Types */

1170 const GLenum FLOAT_VEC2 = 0x8B50;

1171 const GLenum FLOAT_VEC3 = 0x8B51;

1172 const GLenum FLOAT_VEC4 = 0x8B52;

1173 const GLenum INT_VEC2 = 0x8B53;

1174 const GLenum INT_VEC3 = 0x8B54;

1175 const GLenum INT_VEC4 = 0x8B55;

1176 const GLenum BOOL = 0x8B56;

1177 const GLenum BOOL_VEC2 = 0x8B57;

1178 const GLenum BOOL_VEC3 = 0x8B58;

1179 const GLenum BOOL_VEC4 = 0x8B59;

1180 const GLenum FLOAT_MAT2 = 0x8B5A;

1181 const GLenum FLOAT_MAT3 = 0x8B5B;

1182 const GLenum FLOAT_MAT4 = 0x8B5C;

1183 const GLenum SAMPLER_2D = 0x8B5E;

1184 const GLenum SAMPLER_CUBE = 0x8B60;

1185

1186 /* Vertex Arrays */

1187 const GLenum VERTEX_ATTRIB_ARRAY_ENABLED = 0x8622;

1188 const GLenum VERTEX_ATTRIB_ARRAY_SIZE = 0x8623;

1189 const GLenum VERTEX_ATTRIB_ARRAY_STRIDE = 0x8624;

1190 const GLenum VERTEX_ATTRIB_ARRAY_TYPE = 0x8625;

1191 const GLenum VERTEX_ATTRIB_ARRAY_NORMALIZED = 0x886A;

1192 const GLenum VERTEX_ATTRIB_ARRAY_POINTER = 0x8645;

1193 const GLenum VERTEX_ATTRIB_ARRAY_BUFFER_BINDING = 0x889F;

1194

1195 /* Shader Source */

1196 const GLenum COMPILE_STATUS = 0x8B81;

1197

1198 /* Shader Precision-Specified Types */

1199 const GLenum LOW_FLOAT = 0x8DF0;

1200 const GLenum MEDIUM_FLOAT = 0x8DF1;

1201 const GLenum HIGH_FLOAT = 0x8DF2;

1202 const GLenum LOW_INT = 0x8DF3;

1203 const GLenum MEDIUM_INT = 0x8DF4;

1204 const GLenum HIGH_INT = 0x8DF5;

1205

1206 /* Framebuffer Object. */

1207 const GLenum FRAMEBUFFER = 0x8D40;

1208 const GLenum RENDERBUFFER = 0x8D41;

1209

1210 const GLenum RGBA4 = 0x8056;

1211 const GLenum RGB5_A1 = 0x8057;

1212 const GLenum RGB565 = 0x8D62;

1213 const GLenum DEPTH_COMPONENT16 = 0x81A5;

1214 const GLenum STENCIL_INDEX = 0x1901;

1215 const GLenum STENCIL_INDEX8 = 0x8D48;

1216 const GLenum DEPTH_STENCIL = 0x84F9;

1217

1218 const GLenum RENDERBUFFER_WIDTH = 0x8D42;

1219 const GLenum RENDERBUFFER_HEIGHT = 0x8D43;

1220 const GLenum RENDERBUFFER_INTERNAL_FORMAT = 0x8D44;

1221 const GLenum RENDERBUFFER_RED_SIZE = 0x8D50;

1222 const GLenum RENDERBUFFER_GREEN_SIZE = 0x8D51;

1223 const GLenum RENDERBUFFER_BLUE_SIZE = 0x8D52;

1224 const GLenum RENDERBUFFER_ALPHA_SIZE = 0x8D53;

1225 const GLenum RENDERBUFFER_DEPTH_SIZE = 0x8D54;

1226 const GLenum RENDERBUFFER_STENCIL_SIZE = 0x8D55;

1227

1228 const GLenum FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE = 0x8CD0;

1229 const GLenum FRAMEBUFFER_ATTACHMENT_OBJECT_NAME = 0x8CD1;

1230 const GLenum FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL = 0x8CD2;

1231 const GLenum FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE = 0x8CD3;

1232

1233 const GLenum COLOR_ATTACHMENT0 = 0x8CE0;

1234 const GLenum DEPTH_ATTACHMENT = 0x8D00;

1235 const GLenum STENCIL_ATTACHMENT = 0x8D20;

1236 const GLenum DEPTH_STENCIL_ATTACHMENT = 0x821A;

1237

1238 const GLenum NONE = 0;

1239

1240 const GLenum FRAMEBUFFER_COMPLETE = 0x8CD5;

1241 const GLenum FRAMEBUFFER_INCOMPLETE_ATTACHMENT = 0x8CD6;

1242 const GLenum FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT = 0x8CD7;

1243 const GLenum FRAMEBUFFER_INCOMPLETE_DIMENSIONS = 0x8CD9;

1244 const GLenum FRAMEBUFFER_UNSUPPORTED = 0x8CDD;

1245

1246 const GLenum FRAMEBUFFER_BINDING = 0x8CA6;

1247 const GLenum RENDERBUFFER_BINDING = 0x8CA7;

1248 const GLenum MAX_RENDERBUFFER_SIZE = 0x84E8;

1249

1250 const GLenum INVALID_FRAMEBUFFER_OPERATION = 0x0506;

1251

1252 /* WebGL-specific enums */

1253 const GLenum UNPACK_FLIP_Y_WEBGL = 0x9240;

1254 const GLenum UNPACK_PREMULTIPLY_ALPHA_WEBGL = 0x9241;

1255 const GLenum CONTEXT_LOST_WEBGL = 0x9242;

1256 const GLenum UNPACK_COLORSPACE_CONVERSION_WEBGL = 0x9243;

1257 const GLenum BROWSER_DEFAULT_WEBGL = 0x9244;

1258

1259 readonly attribute HTMLCanvasElement canvas;

1260 readonly attribute GLsizei drawingBufferWidth;

1261 readonly attribute GLsizei drawingBufferHeight;

1262

1263 WebGLContextAttributes getContextAttributes();

1264 boolean isContextLost();

1265

1266 DOMString[ ] getSupportedExtensions();

1267 object getExtension(DOMString name);

1268

1269 void activeTexture(GLenum texture);

1270 void attachShader(WebGLProgram program, WebGLShader shader);

1271 void bindAttribLocation(WebGLProgram program, GLuint index, DOMString name);

1272 void bindBuffer(GLenum target, WebGLBuffer buffer);

1273 void bindFramebuffer(GLenum target, WebGLFramebuffer framebuffer);

1274 void bindRenderbuffer(GLenum target, WebGLRenderbuffer renderbuffer);

1275 void bindTexture(GLenum target, WebGLTexture texture);

1276 void blendColor(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha) ;

1277 void blendEquation(GLenum mode);

1278 void blendEquationSeparate(GLenum modeRGB, GLenum modeAlpha);

1279 void blendFunc(GLenum sfactor, GLenum dfactor);

1280 void blendFuncSeparate(GLenum srcRGB, GLenum dstRGB,

1281 GLenum srcAlpha, GLenum dstAlpha);

1282

1283 void bufferData(GLenum target, GLsizeiptr size, GLenum usage);

1284 void bufferData(GLenum target, ArrayBufferView data, GLenum usage);

1285 void bufferData(GLenum target, ArrayBuffer data, GLenum usage);

1286 void bufferSubData(GLenum target, GLintptr offset, ArrayBufferView data);

1287 void bufferSubData(GLenum target, GLintptr offset, ArrayBuffer data);

1288

1289 GLenum checkFramebufferStatus(GLenum target);

1290 void clear(GLbitfield mask);

1291 void clearColor(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha) ;

1292 void clearDepth(GLclampf depth);

1293 void clearStencil(GLint s);

1294 void colorMask(GLboolean red, GLboolean green, GLboolean blue, GLboolean alp ha);

1295 void compileShader(WebGLShader shader);

1296

1297 void copyTexImage2D(GLenum target, GLint level, GLenum internalformat,

1298 GLint x, GLint y, GLsizei width, GLsizei height,

1299 GLint border);

1300 void copyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoff set,

1301 GLint x, GLint y, GLsizei width, GLsizei height);

1302

1303 WebGLBuffer createBuffer();

1304 WebGLFramebuffer createFramebuffer();

1305 WebGLProgram createProgram();

1306 WebGLRenderbuffer createRenderbuffer();

1307 WebGLShader createShader(GLenum type);

1308 WebGLTexture createTexture();

1309

1310 void cullFace(GLenum mode);

1311

1312 void deleteBuffer(WebGLBuffer buffer);

1313 void deleteFramebuffer(WebGLFramebuffer framebuffer);

1314 void deleteProgram(WebGLProgram program);

1315 void deleteRenderbuffer(WebGLRenderbuffer renderbuffer);

1316 void deleteShader(WebGLShader shader);

1317 void deleteTexture(WebGLTexture texture);

1318

1319 void depthFunc(GLenum func);

1320 void depthMask(GLboolean flag);

1321 void depthRange(GLclampf zNear, GLclampf zFar);

1322 void detachShader(WebGLProgram program, WebGLShader shader);

1323 void disable(GLenum cap);

1324 void disableVertexAttribArray(GLuint index);

1325 void drawArrays(GLenum mode, GLint first, GLsizei count);

1326 void drawElements(GLenum mode, GLsizei count, GLenum type, GLintptr offset);

1327

1328 void enable(GLenum cap);

1329 void enableVertexAttribArray(GLuint index);

1330 void finish();

1331 void flush();

1332 void framebufferRenderbuffer(GLenum target, GLenum attachment,

1333 GLenum renderbuffertarget,

1334 WebGLRenderbuffer renderbuffer);

1335 void framebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget ,

1336 WebGLTexture texture, GLint level);

1337 void frontFace(GLenum mode);

1338

1339 void generateMipmap(GLenum target);

1340

1341 WebGLActiveInfo getActiveAttrib(WebGLProgram program, GLuint index);

1342 WebGLActiveInfo getActiveUniform(WebGLProgram program, GLuint index);

1343 WebGLShader[ ] getAttachedShaders(WebGLProgram program);

1344

1345 GLint getAttribLocation(WebGLProgram program, DOMString name);

1346

1347 any getParameter(GLenum pname);

1348 any getBufferParameter(GLenum target, GLenum pname);

1349

1350 GLenum getError();

1351

1352 any getFramebufferAttachmentParameter(GLenum target, GLenum attachment,

1353 GLenum pname);

1354 any getProgramParameter(WebGLProgram program, GLenum pname);

1355 DOMString getProgramInfoLog(WebGLProgram program);

1356 any getRenderbufferParameter(GLenum target, GLenum pname);

1357 any getShaderParameter(WebGLShader shader, GLenum pname);

1358 DOMString getShaderInfoLog(WebGLShader shader);

1359

1360 DOMString getShaderSource(WebGLShader shader);

1361

1362 any getTexParameter(GLenum target, GLenum pname);

1363

1364 any getUniform(WebGLProgram program, WebGLUniformLocation location);

1365

1366 WebGLUniformLocation getUniformLocation(WebGLProgram program, DOMString name );

1367

1368 any getVertexAttrib(GLuint index, GLenum pname);

1369

1370 GLsizeiptr getVertexAttribOffset(GLuint index, GLenum pname);

1371

1372 void hint(GLenum target, GLenum mode);

1373 GLboolean isBuffer(WebGLBuffer buffer);

1374 GLboolean isEnabled(GLenum cap);

1375 GLboolean isFramebuffer(WebGLFramebuffer framebuffer);

1376 GLboolean isProgram(WebGLProgram program);

1377 GLboolean isRenderbuffer(WebGLRenderbuffer renderbuffer);

1378 GLboolean isShader(WebGLShader shader);

1379 GLboolean isTexture(WebGLTexture texture);

1380 void lineWidth(GLfloat width);

1381 void linkProgram(WebGLProgram program);

1382 void pixelStorei(GLenum pname, GLint param);

1383 void polygonOffset(GLfloat factor, GLfloat units);

1384

1385 void readPixels(GLint x, GLint y, GLsizei width, GLsizei height,

1386 GLenum format, GLenum type, ArrayBufferView pixels);

1387

1388 void renderbufferStorage(GLenum target, GLenum internalformat,

1389 GLsizei width, GLsizei height);

1390 void sampleCoverage(GLclampf value, GLboolean invert);

1391 void scissor(GLint x, GLint y, GLsizei width, GLsizei height);

1392

1393 void shaderSource(WebGLShader shader, DOMString source);

1394

1395 void stencilFunc(GLenum func, GLint ref, GLuint mask);

1396 void stencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask);

1397 void stencilMask(GLuint mask);

1398 void stencilMaskSeparate(GLenum face, GLuint mask);

1399 void stencilOp(GLenum fail, GLenum zfail, GLenum zpass);

1400 void stencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass) ;

1401

1402 void texImage2D(GLenum target, GLint level, GLenum internalformat,

1403 GLsizei width, GLsizei height, GLint border, GLenum format,

1404 GLenum type, ArrayBufferView pixels);

1405 void texImage2D(GLenum target, GLint level, GLenum internalformat,

1406 GLenum format, GLenum type, ImageData pixels);

1407 void texImage2D(GLenum target, GLint level, GLenum internalformat,

1408 GLenum format, GLenum type, HTMLImageElement image);

1409 void texImage2D(GLenum target, GLint level, GLenum internalformat,

1410 GLenum format, GLenum type, HTMLCanvasElement canvas);

1411 void texImage2D(GLenum target, GLint level, GLenum internalformat,

1412 GLenum format, GLenum type, HTMLVideoElement video);

1413

1414 void texParameterf(GLenum target, GLenum pname, GLfloat param);

1415 void texParameteri(GLenum target, GLenum pname, GLint param);

1416

1417 void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

1418 GLsizei width, GLsizei height,

1419 GLenum format, GLenum type, ArrayBufferView pixels);

1420 void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

1421 GLenum format, GLenum type, ImageData pixels);

1422 void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

1423 GLenum format, GLenum type, HTMLImageElement image);

1424 void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

1425 GLenum format, GLenum type, HTMLCanvasElement canvas);

1426 void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

1427 GLenum format, GLenum type, HTMLVideoElement video);

1428

1429 void uniform1f(WebGLUniformLocation location, GLfloat x);

1430 void uniform1fv(WebGLUniformLocation location, Float32Array v);

1431 void uniform1fv(WebGLUniformLocation location, float[] v);

1432 void uniform1i(WebGLUniformLocation location, GLint x);

1433 void uniform1iv(WebGLUniformLocation location, Int32Array v);

1434 void uniform1iv(WebGLUniformLocation location, long[] v);

1435 void uniform2f(WebGLUniformLocation location, GLfloat x, GLfloat y);

1436 void uniform2fv(WebGLUniformLocation location, Float32Array v);

1437 void uniform2fv(WebGLUniformLocation location, float[] v);

1438 void uniform2i(WebGLUniformLocation location, GLint x, GLint y);

1439 void uniform2iv(WebGLUniformLocation location, Int32Array v);

1440 void uniform2iv(WebGLUniformLocation location, long[] v);

1441 void uniform3f(WebGLUniformLocation location, GLfloat x, GLfloat y, GLfloat z);

1442 void uniform3fv(WebGLUniformLocation location, Float32Array v);

1443 void uniform3fv(WebGLUniformLocation location, float[] v);

1444 void uniform3i(WebGLUniformLocation location, GLint x, GLint y, GLint z);

1445 void uniform3iv(WebGLUniformLocation location, Int32Array v);

1446 void uniform3iv(WebGLUniformLocation location, long[] v);

1447 void uniform4f(WebGLUniformLocation location, GLfloat x, GLfloat y, GLfloat z, GLfloat w);

1448 void uniform4fv(WebGLUniformLocation location, Float32Array v);

1449 void uniform4fv(WebGLUniformLocation location, float[] v);

1450 void uniform4i(WebGLUniformLocation location, GLint x, GLint y, GLint z, GLi nt w);

1451 void uniform4iv(WebGLUniformLocation location, Int32Array v);

1452 void uniform4iv(WebGLUniformLocation location, long[] v);

1453

1454 void uniformMatrix2fv(WebGLUniformLocation location, GLboolean transpose,

1455 Float32Array value);

1456 void uniformMatrix2fv(WebGLUniformLocation location, GLboolean transpose,

1457 float[] value);

1458 void uniformMatrix3fv(WebGLUniformLocation location, GLboolean transpose,

1459 Float32Array value);

1460 void uniformMatrix3fv(WebGLUniformLocation location, GLboolean transpose,

1461 float[] value);

1462 void uniformMatrix4fv(WebGLUniformLocation location, GLboolean transpose,

1463 Float32Array value);

1464 void uniformMatrix4fv(WebGLUniformLocation location, GLboolean transpose,

1465 float[] value);

1466

1467 void useProgram(WebGLProgram program);

1468 void validateProgram(WebGLProgram program);

1469

1470 void vertexAttrib1f(GLuint indx, GLfloat x);

1471 void vertexAttrib1fv(GLuint indx, Float32Array values);

1472 void vertexAttrib1fv(GLuint indx, float[] values);

1473 void vertexAttrib2f(GLuint indx, GLfloat x, GLfloat y);

1474 void vertexAttrib2fv(GLuint indx, Float32Array values);

1475 void vertexAttrib2fv(GLuint indx, float[] values);

1476 void vertexAttrib3f(GLuint indx, GLfloat x, GLfloat y, GLfloat z);

1477 void vertexAttrib3fv(GLuint indx, Float32Array values);

1478 void vertexAttrib3fv(GLuint indx, float[] values);

1479 void vertexAttrib4f(GLuint indx, GLfloat x, GLfloat y, GLfloat z, GLfloat w) ;

1480 void vertexAttrib4fv(GLuint indx, Float32Array values);

1481 void vertexAttrib4fv(GLuint indx, float[] values);

1482 void vertexAttribPointer(GLuint indx, GLint size, GLenum type,

1483 GLboolean normalized, GLsizei stride, GLintptr offs et);

1484

1485 void viewport(GLint x, GLint y, GLsizei width, GLsizei height);

1486 };</pre>

1487

1488 <!-- =========================================================================== ============================ -->

1489

1490 <h4>Attributes</h4>

1491

1492 <p>

1493 The following attributes are available:

1494 </p>

1495

1496 <dl class="methods">

1497 <dt>

1498 <code class=attribute-name>

1499 <a id="DOM-WebGLRenderingContext-canvas">

1500 canvas

1501 </a>

1502 </code>

1503 of type <code>HTMLCanvasElement</code>

1504 <dd>

1505 A reference to the canvas element which created this context.

1506

1507 <dt>

1508 <code class=attribute-name>

1509 <a id="DOM-WebGLRenderingContext-drawingBufferWidth">

1510 drawingBufferWidth

1511 </a>

1512 </code>

1513 of type <code>GLsizei</code>

1514 <dd>

1515 The actual width of the drawing buffer. May be different from the

1516 <code>width</code> attribute of the <code>HTMLCanvasElement</code> i f

1517 the implementation is unable to satisfy the requested widthor height .

1518

1519 <dt>

1520 <code class=attribute-name>

1521 <a id="DOM-WebGLRenderingContext-drawingBufferHeight">

1522 drawingBufferHeight

1523 </a>

1524 </code>

1525 of type <code>GLsizei</code>

1526 <dd>

1527 The actual height of the drawing buffer. May be different from the

1528 <code>height</code> attribute of the <code>HTMLCanvasElement</code> if

1529 the implementation is unable to satisfy the requested width or heigh t.

1530 </dl>

1531

1532 <!-- =========================================================================== ============================ -->

1533

1534 <h4>Getting information about the context</h4>

1535

1536 <dl class="methods">

1537 <dt class="idl-code">WebGLContextAttributes getContextAttributes()

1538 <dd>

1539 Returns the WebGLContextAttributes describing the current drawing bu ffer.

1540 </dl>

1541

1542 <!-- =========================================================================== ============================ -->

1543

1544 <h4>Setting and getting state</h4>

1545

1546 <p>

1547 OpenGL ES 2.0 maintains state values for use in rendering. All the calls in this

1548 group behave identically to their OpenGL counterparts unless otherwise n oted.

1549 </p>

1550

1551 <dl class="methods">

1552 <dt class="idl-code">void activeTexture(GLenum texture)

1553 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7">OpenGL ES 2.0 §3. 7</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glActiveTexture.xml">man page</a>)</span>

1554 <dt class="idl-code"void blendColor(GLclampf red, GLclampf green, GLclam pf blue, GLclampf alpha)

1555 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.6">OpenGL ES 2.0 § 4.1.6</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glBlendColor.xml">man page</a>)</span>

1556 <dt class="idl-code">void blendEquation(GLenum mode)

1557 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.6">OpenGL ES 2.0 § 4.1.6</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glBlendEquation.xml">man page</a>)</span>

1558 <dt class="idl-code">void blendEquationSeparate(GLenum modeRGB, GLenum m odeAlpha)

1559 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.6">OpenGL ES 2.0 § 4.1.6</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glBlendEquationSeparate.xml">man page</a>)</span>

1560 <dt class="idl-code">void blendFunc(GLenum sfactor, GLenum dfactor)

1561 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.6">OpenGL ES 2.0 § 4.1.6</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glBlendFunc.xml">man page</a>)</span>

1562 <dd>

1563 See <a href="#CONSTANT_COLOR_BLEND">Blending With Constant Color </a> for limitations imposed

1564 by WebGL.

1565 <dt class="idl-code">void blendFuncSeparate(GLenum srcRGB, GLenum dstRGB , GLenum srcAlpha, GLenum dstAlpha)

1566 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.6">OpenGL ES 2.0 § 4.1.6</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glBlendFuncSeparate.xml">man page</a>)</span>

1567 <dd>

1568 See <a href="#CONSTANT_COLOR_BLEND">Blending With Constant Color </a> for limitations imposed

1569 by WebGL.

1570 <dt class="idl-code">void clearColor(GLclampf red, GLclampf green, GLcla mpf blue, GLclampf alpha)

1571 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.3">OpenGL ES 2.0 § 4.2.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glClearColor.xml">man page</a>)</span>

1572 <dt class="idl-code">void clearDepth(GLclampf depth)

1573 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.3">OpenGL ES 2.0 § 4.2.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glClearDepthf.xml">man page</a>)</span>

1574 <dd>

1575 <code>depth</code> value is clamped to the range 0 to 1.

1576 <dt class="idl-code">void clearStencil(GLint s)

1577 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.3">OpenGL ES 2.0 § 4.2.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glClearStencil.xml">man page</a>)</span>

1578 <dt class="idl-code">void colorMask(GLboolean red, GLboolean green, GLbo olean blue, GLboolean alpha)

1579 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.2">OpenGL ES 2.0 § 4.2.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glColorMask.xml">man page</a>)</span>

1580 <dt class="idl-code">void cullFace(GLenum mode)

1581 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.5.1">OpenGL ES 2.0 § 3.5.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glCullFace.xml">man page</a>)</span>

1582 <dt class="idl-code">void depthFunc(GLenum func)

1583 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.5">OpenGL ES 2.0 § 4.1.5</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glDepthFunc.xml">man page</a>)</span>

1584 <dt class="idl-code">void depthMask(GLboolean flag)

1585 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.2">OpenGL ES 2.0 § 4.2.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glDepthMask.xml">man page</a>)</span>

1586 <dt class="idl-code">void depthRange(GLclampf zNear, GLclampf zFar)

1587 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.12.1">OpenGL ES 2.0 &sect ;2.12.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glDepthRangef.xml">man page</a>)</span>

1588 <dd>

1589 <code>zNear</code> and <code>zFar</code> values are clamped to t he range 0 to 1 and

1590 <code>zNear</code> must be less than or equal to <code>zFar</cod e>; see

1591 <a href="#VIEWPORT_DEPTH_RANGE">Viewport Depth Range</a>.

1592 <dt class="idl-code">void disable(GLenum cap)

1593 <span class="gl-spec">(<a class="nonnormative" href="http://www.khro nos.org/opengles/sdk/2.0/docs/man/glDisable.xml">man page</a>)</span>

1594 <dt class="idl-code">void enable(GLenum cap)

1595 <span class="gl-spec">(<a class="nonnormative" href="http://www.khro nos.org/opengles/sdk/2.0/docs/man/glEnable.xml">man page</a>)</span>

1596 <dt class="idl-code">void frontFace(GLenum mode)

1597 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.5.1">OpenGL ES 2.0 § 3.5.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glFrontFace.xml">man page</a>)</span>

1598 <dt class="idl-code">any getParameter(GLenum pname)

1599 <a class="gl-spec" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glGet.xml">

1600 (glGet OpenGL ES 2.0 man page)

1601 </a>

1602 <a class="gl-spec" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glGetString.xml">

1603 (glGetString OpenGL ES 2.0 man page)

1604 </a>

1605 <dd>

1606 Return the value for the passed pname. The type returned is the natu ral type for the

1607 requested pname, as given in the following table:

1608 <table class="foo">

1609 <tr><th>pname</th><th>returned type</th></tr>

1610 <tr><td>ACTIVE_TEXTURE</td><td>unsigned long</td></tr>

1611 <tr><td>ALIASED_LINE_WIDTH_RANGE</td><td>Float32Array (with 2 el ements)</td></tr>

1612 <tr><td>ALIASED_POINT_SIZE_RANGE</td><td>Float32Array (with 2 el ements)</td></tr>

1613 <tr><td>ALPHA_BITS</td><td>long</td></tr>

1614 <tr><td>ARRAY_BUFFER_BINDING</td><td>WebGLBuffer</td></tr>

1615 <tr><td>BLEND</td><td>boolean</td></tr>

1616 <tr><td>BLEND_COLOR</td><td>Float32Array (with 4 values)</td></t r>

1617 <tr><td>BLEND_DST_ALPHA</td><td>unsigned long</td></tr>

1618 <tr><td>BLEND_DST_RGB</td><td>unsigned long</td></tr>

1619 <tr><td>BLEND_EQUATION_ALPHA</td><td>unsigned long</td></tr>

1620 <tr><td>BLEND_EQUATION_RGB</td><td>unsigned long</td></tr>

1621 <tr><td>BLEND_SRC_ALPHA</td><td>unsigned long</td></tr>

1622 <tr><td>BLEND_SRC_RGB</td><td>unsigned long</td></tr>

1623 <tr><td>BLUE_BITS</td><td>long</td></tr>

1624 <tr><td>COLOR_CLEAR_VALUE</td><td>Float32Array (with 4 values)</ td></tr>

1625 <tr><td>COLOR_WRITEMASK</td><td>boolean[] (with 4 values)</td></ tr>

1626 <tr><td>COMPRESSED_TEXTURE_FORMATS</td><td>null</td></tr>

1627 <tr><td>CULL_FACE</td><td>boolean</td></tr>

1628 <tr><td>CULL_FACE_MODE</td><td>unsigned long</td></tr>

1629 <tr><td>CURRENT_PROGRAM</td><td>WebGLProgram</td></tr>

1630 <tr><td>DEPTH_BITS</td><td>long</td></tr>

1631 <tr><td>DEPTH_CLEAR_VALUE</td><td>float</td></tr>

1632 <tr><td>DEPTH_FUNC</td><td>unsigned long</td></tr>

1633 <tr><td>DEPTH_RANGE</td><td>Float32Array (with 2 elements)</td>< /tr>

1634 <tr><td>DEPTH_TEST</td><td>boolean</td></tr>

1635 <tr><td>DEPTH_WRITEMASK</td><td>boolean</td></tr>

1636 <tr><td>DITHER</td><td>boolean</td></tr>

1637 <tr><td>ELEMENT_ARRAY_BUFFER_BINDING</td><td>WebGLBuffer</td></t r>

1638 <tr><td>FRAMEBUFFER_BINDING</td><td>WebGLFramebuffer</td></tr>

1639 <tr><td>FRONT_FACE</td><td>unsigned long</td></tr>

1640 <tr><td>GENERATE_MIPMAP_HINT</td><td>unsigned long</td></tr>

1641 <tr><td>GREEN_BITS</td><td>long</td></tr>

1642 <tr><td>LINE_WIDTH</td><td>float</td></tr>

1643 <tr><td>MAX_COMBINED_TEXTURE_IMAGE_UNITS</td><td>long</td></tr>

1644 <tr><td>MAX_CUBE_MAP_TEXTURE_SIZE</td><td>long</td></tr>

1645 <tr><td>MAX_FRAGMENT_UNIFORM_VECTORS</td><td>long</td></tr>

1646 <tr><td>MAX_RENDERBUFFER_SIZE</td><td>long</td></tr>

1647 <tr><td>MAX_TEXTURE_IMAGE_UNITS</td><td>long</td></tr>

1648 <tr><td>MAX_TEXTURE_SIZE</td><td>long</td></tr>

1649 <tr><td>MAX_VARYING_VECTORS</td><td>long</td></tr>

1650 <tr><td>MAX_VERTEX_ATTRIBS</td><td>long</td></tr>

1651 <tr><td>MAX_VERTEX_TEXTURE_IMAGE_UNITS</td><td>long</td></tr>

1652 <tr><td>MAX_VERTEX_UNIFORM_VECTORS</td><td>long</td></tr>

1653 <tr><td>MAX_VIEWPORT_DIMS</td><td>Int32Array (with 2 elements)</ td></tr>

1654 <tr><td>NUM_COMPRESSED_TEXTURE_FORMATS</td><td>long</td></tr>

1655 <tr><td>PACK_ALIGNMENT</td><td>long</td></tr>

1656 <tr><td>POLYGON_OFFSET_FACTOR</td><td>float</td></tr>

1657 <tr><td>POLYGON_OFFSET_FILL</td><td>boolean</td></tr>

1658 <tr><td>POLYGON_OFFSET_UNITS</td><td>float</td></tr>

1659 <tr><td>RED_BITS</td><td>long</td></tr>

1660 <tr><td>RENDERBUFFER_BINDING</td><td>WebGLRenderbuffer</td></tr>

1661 <tr><td>RENDERER</td><td>DOMString</td></tr>

1662 <tr><td>SAMPLE_BUFFERS</td><td>long</td></tr>

1663 <tr><td>SAMPLE_COVERAGE_INVERT</td><td>boolean</td></tr>

1664 <tr><td>SAMPLE_COVERAGE_VALUE</td><td>float</td></tr>

1665 <tr><td>SAMPLES</td><td>long</td></tr>

1666 <tr><td>SCISSOR_BOX</td><td>Int32Array (with 4 elements)</td></t r>

1667 <tr><td>SCISSOR_TEST</td><td>boolean</td></tr>

1668 <tr><td>SHADING_LANGUAGE_VERSION</td><td>DOMString</td></tr>

1669 <tr><td>STENCIL_BACK_FAIL</td><td>unsigned long</td></tr>

1670 <tr><td>STENCIL_BACK_FUNC</td><td>unsigned long</td></tr>

1671 <tr><td>STENCIL_BACK_PASS_DEPTH_FAIL</td><td>unsigned long</td>< /tr>

1672 <tr><td>STENCIL_BACK_PASS_DEPTH_PASS</td><td>unsigned long</td>< /tr>

1673 <tr><td>STENCIL_BACK_REF</td><td>long</td></tr>

1674 <tr><td>STENCIL_BACK_VALUE_MASK</td><td>unsigned long</td></tr>

1675 <tr><td>STENCIL_BACK_WRITEMASK</td><td>unsigned long</td></tr>

1676 <tr><td>STENCIL_BITS</td><td>long</td></tr>

1677 <tr><td>STENCIL_CLEAR_VALUE</td><td>long</td></tr>

1678 <tr><td>STENCIL_FAIL</td><td>unsigned long</td></tr>

1679 <tr><td>STENCIL_FUNC</td><td>unsigned long</td></tr>

1680 <tr><td>STENCIL_PASS_DEPTH_FAIL</td><td>unsigned long</td></tr>

1681 <tr><td>STENCIL_PASS_DEPTH_PASS</td><td>unsigned long</td></tr>

1682 <tr><td>STENCIL_REF</td><td>long</td></tr>

1683 <tr><td>STENCIL_TEST</td><td>boolean</td></tr>

1684 <tr><td>STENCIL_VALUE_MASK</td><td>unsigned long</td></tr>

1685 <tr><td>STENCIL_WRITEMASK</td><td>unsigned long</td></tr>

1686 <tr><td>SUBPIXEL_BITS</td><td>long</td></tr>

1687 <tr><td>TEXTURE_BINDING_2D</td><td>WebGLTexture</td></tr>

1688 <tr><td>TEXTURE_BINDING_CUBE_MAP</td><td>WebGLTexture</td></tr>

1689 <tr><td>UNPACK_ALIGNMENT</td><td>int</td></tr>

1690 <tr><td>UNPACK_COLORSPACE_CONVERSION_WEBGL</td><td>unsigned long </td></tr>

1691 <tr><td>UNPACK_FLIP_Y_WEBGL</td><td>boolean</td></tr>

1692 <tr><td>UNPACK_PREMULTIPLY_ALPHA_WEBGL</td><td>boolean</td></tr>

1693 <tr><td>VENDOR</td><td>DOMString</td></tr>

1694 <tr><td>VERSION</td><td>DOMString</td></tr>

1695 <tr><td>VIEWPORT</td><td>Int32Array (with 4 elements)</td></tr>

1696 </table><br>

1697 <p>The following <em>pname</em> arguments return a string describing some aspect of the current WebGL implementation:</p>

1698 <table>

1699 <tr><td>VERSION</td>

1700 <td>Returns a version or release number of the form <code>WebG L<space>1.0<space><vendor-specific information></code>.</td></ tr>

1701 <tr><td>SHADING_LANGUAGE_VERSION</td>

1702 <td>Returns a version or release number of the form <code>WebG L<space>GLSL<space>ES<space>1.0<space><vendor-specifi c information></code>.</td></tr>

1703 <tr><td>VENDOR</td>

1704 <td>Returns the company responsible for this WebGL implementat ion. This name does not change from release to release.</td></tr>

1705 <tr><td>RENDERER</td>

1706 <td>Returns the name of the renderer. This name is typically s pecific to a particular configuration of a hardware platform. It does not change from release to release.</td></tr>

1707 </table><br>

1708 <p>See <a href="#EXTENSION_QUERIES">Extension Queries</a> for inform ation on querying the

1709 available extensions in the current WebGL implementation.</p>

1710 <dt class="idl-code">GLenum getError()

1711 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.5">OpenGL ES 2.0 §2. 5</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glGetError.xml">man page</a>)</span>

1712 <dd>

1713 See <a href="#WEBGLCONTEXTEVENT">WebGLContextEvent</a> for documenta tion of a

1714 WebGL-specific return value from getError.

1715 <dt class="idl-code">void hint(GLenum target, GLenum mode)

1716 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-5.2">OpenGL ES 2.0 §5. 2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glHint.xml">man page</a>)</span>

1717 <dt class="idl-code">GLboolean isEnabled(GLenum cap)

1718 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.1">OpenGL ES 2.0 § 6.1.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glIsEnabled.xml">man page</a>)</span>

1719 <dt class="idl-code">void lineWidth(GLfloat width)

1720 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.4">OpenGL ES 2.0 §3. 4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glLineWidth.xml">man page</a>)</span>

1721 <dt class="idl-code">void pixelStorei(GLenum pname, GLint param)

1722 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.6.1">OpenGL ES 2.0 § 3.6.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glPixelStorei.xml">man page</a>)</span>

1723 <dd>

1724 In addition to the parameters in the OpenGL ES 2.0 specification , the WebGL

1725 specification accepts the parameters <code>UNPACK_FLIP_Y_WEBGL</ code>,

1726 <code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code>

1727 and <code>UNPACK_COLORSPACE_CONVERSION_WEBGL</code>. See <a href ="#PIXEL_STORAGE_PARAMETERS">Pixel

1728 Storage Parameters</a> for documentation of these parameters.

1729 <dt class="idl-code">void polygonOffset(GLfloat factor, GLfloat units)

1730 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.5.2">OpenGL ES 2.0 § 3.5.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glPolygonOffset.xml">man page</a>)</span>

1731 <dt class="idl-code">void sampleCoverage(GLclampf value, GLboolean inver t)

1732 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.3">OpenGL ES 2.0 § 4.1.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glSampleCoverage.xml">man page</a>)</span>

1733 <dt class="idl-code">void stencilFunc(GLenum func, GLint ref, GLuint mas k)

1734 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.4">OpenGL ES 2.0 § 4.1.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glStencilFunc.xml">man page</a>)</span>

1735 <dt class="idl-code">void stencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)

1736 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.4">OpenGL ES 2.0 § 4.1.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glStencilFuncSeparate.xml">man page</a>)</span>

1737 <dd>

1738 See <a href="#STENCIL_SEPARATE_LIMIT">Stencil Separate Mask and Reference Value</a> for information

1739 on WebGL specific limitations to the allowable argument values.

1740 <dt class="idl-code">void stencilMask(GLuint mask)

1741 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.2">OpenGL ES 2.0 § 4.2.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glStencilMask.xml">man page</a>)</span>

1742 <dd>

1743 See <a href="#STENCIL_SEPARATE_LIMIT">Stencil Separate Mask and Reference Value</a> for information

1744 on WebGL specific limitations to the allowable mask values.

1745 <dt class="idl-code">void stencilMaskSeparate(GLenum face, GLuint mask)

1746 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.2">OpenGL ES 2.0 § 4.2.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glStencilMaskSeparate.xml">man page</a>)</span>

1747 <dt class="idl-code">void stencilOp(GLenum fail, GLenum zfail, GLenum zp ass)

1748 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.4">OpenGL ES 2.0 § 4.1.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glStencilOp.xml">man page</a>)</span>

1749 <dt class="idl-code">void stencilOpSeparate(GLenum face, GLenum fail, GL enum zfail, GLenum zpass)

1750 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.4">OpenGL ES 2.0 § 4.1.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glStencilOpSeparate.xml">man page</a>)</span>

1751 </dl>

1752

1753 <!-- =========================================================================== ============================ -->

1754

1755 <h4>Viewing and clipping</h4>

1756

1757 <p>

1758 The viewport specifies the affine transformation of x and y from normali zed device

1759 coordinates to window coordinates. The size of the drawing buffer is det ermined by

1760 the HTMLCanvasElement. The scissor box defines a rectangle which constra ins drawing.

1761 When the scissor test is enabled only pixels that lie within the scisso r box can

1762 be modified by drawing commands. When enabled drawing can only occur ins ide the

1763 intersection of the viewport, canvas area and the scissor box. When the scissor test

1764 is not enabled drawing can only occur inside the intersection of the vie wport and

1765 canvas area.

1766 </p>

1767

1768 <dl class="methods">

1769 <dt class="idl-code">void scissor(GLint x, GLint y, GLsizei width, GLsiz ei height)

1770 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.1.2">OpenGL ES 2.0 § 4.1.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glScissor.xml">man page</a>)</span>

1771

1772 <dt class="idl-code">void viewport(GLint x, GLint y, GLsizei width, GLsi zei height)

1773 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.12.1">OpenGL ES 2.0 &sect ;2.12.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glViewport.xml">man page</a>)</span>

1774 </dl>

1775

1776 <!-- =========================================================================== ============================ -->

1777

1778 <h4>Buffer objects</h4>

1779

1780 <p>

1781 Buffer objects (sometimes referred to as VBOs) hold vertex attribute dat a for the GLSL

1782 shaders.

1783 </p>

1784

1785 <dl class="methods">

1786 <dt class="idl-code">void bindBuffer(GLenum target, WebGLBuffer buffer)

1787 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2. 9</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glBindBuffer.xml">man page</a>)</span>

1788 <dd>

1789 Binds the given WebGLBuffer object to the given binding point (targe t), either

1790 ARRAY_BUFFER or ELEMENT_ARRAY_BUFFER. If the buffer is null then any buffer currently

1791 bound to this target is unbound. A given WebGLBuffer object may only be bound to one of

1792 the ARRAY_BUFFER or ELEMENT_ARRAY_BUFFER target in its lifetime. An attempt to bind a

1793 buffer object to the other target will generate an <code>INVALID_OPE RATION</code> error, and the

1794 current binding will remain untouched.

1795

1796 <dt class="idl-code">void bufferData(GLenum target, GLsizeiptr size, GLe num usage)

1797 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2. 9</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glBufferData.xml">man page</a>)</span>

1798 <dd>

1799 Set the size of the currently bound WebGLBuffer object for the passe d target. The

1800 buffer is initialized to 0.

1801

1802 <dt><p class="idl-code">void bufferData(GLenum target, ArrayBufferView d ata, GLenum usage)</p>

1803 <p class="idl-code">void bufferData(GLenum target, ArrayBuffer data, GLenum usage)

1804 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2. 9</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glBufferData.xml">man page</a>)</span></p>

1805 <dd>

1806 Set the size of the currently bound WebGLBuffer object for the passe d target to the

1807 size of the passed data, then write the contents of data to the buff er object.

1808 <br><br>

1809 If the passed data is null then an <code>INVALID_VALUE</code> error is generated.

1810 <dt><p class="idl-code">void bufferSubData(GLenum target, GLintptr offse t, ArrayBufferView data)</p>

1811 <p class="idl-code">void bufferSubData(GLenum target, GLintptr offse t, ArrayBuffer data)

1812 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2. 9</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glBufferSubData.xml">man page</a>)</span></p>

1813 <dd>

1814 For the WebGLBuffer object bound to the passed target write the pass ed data starting

1815 at the passed offset. If the data would be written past the end of t he buffer object

1816 an <code>INVALID_VALUE</code> error is generated.

1817

1818 <dt class="idl-code">WebGLBuffer createBuffer()

1819 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2. 9</a>, similar to <a class="nonnormative" href="http://www.khronos.org/opengles/ sdk/2.0/docs/man/glGenBuffers.xml">glGenBuffers</a>)</span>

1820 <dd>

1821 Create a WebGLBuffer object and initialize it with a buffer object n ame as if by

1822 calling glGenBuffers.

1823

1824 <dt class="idl-code">void deleteBuffer(WebGLBuffer buffer)

1825 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.9">OpenGL ES 2.0 §2. 9</a>, similar to <a class="nonnormative" href="http://www.khronos.org/opengles/ sdk/2.0/docs/man/glDeleteBuffers.xml">glDeleteBuffers</a>)</span>

1826 <dd>

1827 Delete the buffer object contained in the passed WebGLBuffer as if b y calling

1828 glDeleteBuffers. If the buffer has already been deleted the call has no effect.

1829 Note that the buffer object will be deleted when the WebGLBuffer obj ect is destroyed.

1830 This method merely gives the author greater control over when the bu ffer object is

1831 destroyed.

1832

1833 <dt class="idl-code">any getBufferParameter(GLenum target, GLenum pname)

1834 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.3">OpenGL ES 2.0 § 6.1.3</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGetBufferParameteriv.xml">glGetBufferParameteriv</a>)</sp an>

1835 <dd>

1836 Return the value for the passed pname. The type returned is the natu ral type for the

1837 requested pname, as given in the following table:

1838 <table class="foo">

1839 <tr><th>pname</th><th>returned type</th></tr>

1840 <tr><td>BUFFER_SIZE</td><td>long</td></tr>

1841 <tr><td>BUFFER_USAGE</td><td>unsigned long</td></tr>

1842 </table>

1843 <dt class="idl-code">GLboolean isBuffer(WebGLBuffer buffer)

1844 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.6">OpenGL ES 2.0 § 6.1.6</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glIsBuffer.xml">man page</a>)</span>

1845 </dl>

1846

1847 <!-- =========================================================================== ============================ -->

1848

1849 <h4>Framebuffer objects</h4>

1850

1851 <p>

1852 Framebuffer objects provide an alternative rendering target to the drawi ng buffer. They

1853 are a collection of color, alpha, depth and stencil buffers and are ofte n used to

1854 render an image that will later be used as a texture.

1855 </p>

1856

1857 <dl class="methods">

1858 <dt class="idl-code">void bindFramebuffer(GLenum target, WebGLFramebuffe r framebuffer)

1859 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.1">OpenGL ES 2.0 § 4.4.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glBindFramebuffer.xml">man page</a>)</span>

1860 <dd>

1861 Bind the given <code class="interface">WebGLFramebuffer</code> objec t to the given binding point

1862 (<code class="param">target</code>), which must be <code class="enum ">FRAMEBUFFER</code>.

1863 If <code class="param">framebuffer</code> is null, the default frame buffer provided by the context

1864 is bound and attempts to modify or query state on <code class="param ">target</code> <code class="enum">FRAMEBUFFER</code>

1865 will generate an <code class="error">INVALID_OPERATION</code> error.

1866

1867 <dt class="idl-code">GLenum checkFramebufferStatus(GLenum target)

1868 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.5">OpenGL ES 2.0 § 4.4.5</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glCheckFramebufferStatus.xml">man page</a>)</span>

1869 <dt class="idl-code">WebGLFramebuffer createFramebuffer()

1870 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.1">OpenGL ES 2.0 § 4.4.1</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGenFramebuffers.xml">glGenFramebuffers</a>)</span>

1871 <dd>

1872 Create a WebGLFramebuffer object and initialize it with a framebuffe r object name as if by

1873 calling glGenFramebuffers.

1874

1875 <dt class="idl-code">void deleteFramebuffer(WebGLFramebuffer buffer)

1876 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.1">OpenGL ES 2.0 § 4.4.1</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glDeleteFramebuffers.xml">glDeleteFramebuffers</a>)</span>

1877 <dd>

1878 Delete the framebuffer object contained in the passed WebGLFramebuff er as if by calling

1879 glDeleteFramebuffers. If the framebuffer has already been deleted th e call has no effect.

1880 Note that the framebuffer object will be deleted when the WebGLFrame buffer object is destroyed.

1881 This method merely gives the author greater control over when the fr amebuffer object is

1882 destroyed.

1883

1884 <dt class="idl-code">void framebufferRenderbuffer(GLenum target, GLenum attachment,

1885 GLenum renderbuffertarget,

1886 WebGLRenderbuffer renderbuffer)

1887 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 § 4.4.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glFramebufferRenderbuffer.xml">man page</a>)</span></dt>

1888 <dt class="idl-code">void framebufferTexture2D(GLenum target, GLenum att achment, GLenum textarget,

1889 WebGLTexture texture, GLint level)

1890 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 § 4.4.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glFramebufferTexture2D.xml">man page</a>)</span>

1891 <dt class="idl-code">any getFramebufferAttachmentParameter(GLenum target , GLenum attachment,

1892 GLenum pname)

1893 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.3">OpenGL ES 2.0 § 6.1.3</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGetFramebufferAttachmentParameteriv.xml">glGetFramebuffer AttachmentParameteriv</a>)</span>

1894 <dd>

1895 Return the value for the passed pname given the passed target and at tachment. The type

1896 returned is the natural type for the requested pname, as given in th e following table:

1897 <table class="foo">

1898 <tr><th>pname</th><th>returned type</th></tr>

1899 <tr><td>FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE</td><td>unsigned long </td></tr>

1900 <tr><td>FRAMEBUFFER_ATTACHMENT_OBJECT_NAME</td><td>WebGLRenderbu ffer or WebGLTexture</td></tr>

1901 <tr><td>FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL</td><td>long</td></ tr>

1902 <tr><td>FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE</td><td>lon g</td></tr>

1903 </table>

1904 <dt class="idl-code">GLboolean isFramebuffer(WebGLFramebuffer framebuffe r)

1905 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.7">OpenGL ES 2.0 § 6.1.7</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glIsFramebuffer.xml">man page</a>)</span>

1906 <dd>

1907 Return true if the passed WebGLFramebuffer is valid and false otherw ise.

1908 </dl>

1909

1910 <!-- =========================================================================== ============================ -->

1911

1912 <h4>Renderbuffer objects</h4>

1913

1914 <p>

1915 Renderbuffer objects are used to provide storage for the individual buff ers used in a

1916 framebuffer object.

1917 </p>

1918

1919 <dl class="methods">

1920 <dt class="idl-code">void bindRenderbuffer(GLenum target, WebGLRenderbuf fer renderbuffer)

1921 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 § 4.4.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glBindRenderbuffer.xml">man page</a>)</span>

1922 <dd>

1923 Bind the given <code class="interface">WebGLRenderbuffer</code> obje ct to the given binding point

1924 (<code class="param">target</code>), which must be <code class="enum ">RENDERBUFFER</code>.

1925 If <code class="param">renderbuffer</code> is null the renderbuffer object currently bound to

1926 this <code class="param">target</code> is unbound.

1927

1928 <dt class="idl-code">WebGLRenderbuffer createRenderbuffer()

1929 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 § 4.4.3</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGenRenderbuffers.xml">glGenRenderbuffers</a>)</span>

1930 <dd>

1931 Create a WebGLRenderbuffer object and initialize it with a renderbuf fer object name as if by

1932 calling glGenRenderbuffers.

1933

1934 <dt class="idl-code">void deleteRenderbuffer(WebGLRenderbuffer renderbuf fer)

1935 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 § 4.4.3</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glDeleteRenderbuffers.xml">glDeleteRenderbuffers</a>)</span >

1936 <dd>

1937 Delete the renderbuffer object contained in the passed WebGLRenderbu ffer as if by calling

1938 glDeleteRenderbuffers. If the renderbuffer has already been deleted the call has no effect.

1939 Note that the renderbuffer object will be deleted when the WebGLRend erbuffer object is destroyed.

1940 This method merely gives the author greater control over when the re nderbuffer object is

1941 destroyed.

1942 <dt class="idl-code">any getRenderbufferParameter(GLenum target, GLenum pname)

1943 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.3">OpenGL ES 2.0 § 6.1.3</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGetRenderbufferParameteriv.xml">glGetRenderbufferParamete riv</a>)</span>

1944 <dd>

1945 Return the value for the passed pname given the passed target. The t ype returned is the natural

1946 type for the requested pname, as given in the following table:

1947 <table class="foo">

1948 <tr><th>pname</th><th>returned type</th></tr>

1949 <tr><td>RENDERBUFFER_WIDTH</td><td>long</td></tr>

1950 <tr><td>RENDERBUFFER_HEIGHT</td><td>long</td></tr>

1951 <tr><td>RENDERBUFFER_INTERNAL_FORMAT</td><td>unsigned long</td>< /tr>

1952 <tr><td>RENDERBUFFER_RED_SIZE</td><td>long</td></tr>

1953 <tr><td>RENDERBUFFER_GREEN_SIZE</td><td>long</td></tr>

1954 <tr><td>RENDERBUFFER_BLUE_SIZE</td><td>long</td></tr>

1955 <tr><td>RENDERBUFFER_ALPHA_SIZE</td><td>long</td></tr>

1956 <tr><td>RENDERBUFFER_DEPTH_SIZE</td><td>long</td></tr>

1957 <tr><td>RENDERBUFFER_STENCIL_SIZE</td><td>long</td></tr>

1958 </table>

1959 <dt class="idl-code">GLboolean isRenderbuffer(WebGLRenderbuffer renderbu ffer)

1960 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.7">OpenGL ES 2.0 § 6.1.7</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glIsRenderbuffer.xml">man page</a>)</span>

1961 <dd>

1962 Return true if the passed WebGLRenderbuffer is valid and false other wise.

1963 <dt class="idl-code">void renderbufferStorage(GLenum target, GLenum inte rnalformat,

1964 GLsizei width, GLsizei height)

1965 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.4.3">OpenGL ES 2.0 § 4.4.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glRenderbufferStorage.xml">man page</a>)</span>

1966 </dl>

1967

1968 <!-- =========================================================================== ============================ -->

1969

1970 <h4>Texture objects</h4>

1971

1972 <p>

1973 Texture objects provide storage and state for texturing operations. If n o WebGLTexture is bound

1974 (e.g., passing null or 0 to bindTexture) then attempts to modify or quer y the texture object shall

1975 generate an <code>INVALID_OPERATION</code> error. This is indicated in t he functions below.

1976 </p>

1977

1978 <dl class="methods">

1979 <dt class="idl-code">void bindTexture(GLenum target, WebGLTexture textur e)

1980 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.13">OpenGL ES 2.0 &sect ;3.7.13</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glBindTexture.xml">man page</a>)</span>

1981 <dt class="idl-code">void copyTexImage2D(GLenum target, GLint level, GLe num internalformat,

1982 GLint x, GLint y, GLsizei width, GLsizei height,

1983 GLint border)

1984 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.2">OpenGL ES 2.0 § 3.7.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glCopyTexImage2D.xml">man page</a>)</span>

1985 <dd>

1986 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

1987 <code>INVALID_OPERATION</code> error is generated. <br><br>

1988

1989 For any pixel lying outside the frame buffer, all channels of the as sociated texel are

1990 initialized to 0; see <a href="#READS_OUTSIDE_FRAMEBUFFER">Reading P ixels Outside the

1991 Framebuffer</a>.

1992 <dt class="idl-code">void copyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

1993 GLint x, GLint y, GLsizei width, GLsizei height)

1994 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.2">OpenGL ES 2.0 § 3.7.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glCopyTexSubImage2D.xml">man page</a>)</span>

1995 <dd>

1996 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

1997 <code>INVALID_OPERATION</code> error is generated. <br><br>

1998

1999 For any pixel lying outside the frame buffer, all channels of the as sociated texel are

2000 initialized to 0; see <a href="#READS_OUTSIDE_FRAMEBUFFER">Reading P ixels Outside the

2001 Framebuffer</a>.

2002 <dt class="idl-code">WebGLTexture createTexture()

2003 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.13">OpenGL ES 2.0 &sect ;3.7.13</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glGenTextures.xml">man page</a>)</span>

2004 <dd>

2005 Create a WebGLTexture object and initialize it with a texture object name as if by

2006 calling glGenTextures.

2007

2008 <dt class="idl-code">void deleteTexture(WebGLTexture texture)

2009 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.13">OpenGL ES 2.0 &sect ;3.7.13</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glDeleteTextures.xml">man page</a>)</span>

2010 <dd>

2011 Delete the texture object contained in the passed WebGLTexture as if by calling

2012 glDeleteTextures. If the texture has already been deleted the call h as no effect.

2013 Note that the texture object will be deleted when the WebGLTexture o bject is destroyed.

2014 This method merely gives the author greater control over when the te xture object is

2015 destroyed.

2016 <dt class="idl-code">void generateMipmap(GLenum target)

2017 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.11">OpenGL ES 2.0 &sect ;3.7.11</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glGenerateMipmap.xml">man page</a>)</span>

2018 <dd>

2019 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2020 <code>INVALID_OPERATION</code> error is generated.

2021 <dt class="idl-code">any getTexParameter(GLenum target, GLenum pname)

2022 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.3">OpenGL ES 2.0 § 6.1.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glGetTexParameter.xml">man page</a>)</span>

2023 <dd>

2024 Return the value for the passed pname given the passed target. The t ype returned is the natural type for the

2025 requested pname, as given in the following table:

2026 <table class="foo">

2027 <tr><th>pname</th><th>returned type</th></tr>

2028 <tr><td>TEXTURE_MAG_FILTER</td><td>unsigned long</td></tr>

2029 <tr><td>TEXTURE_MIN_FILTER</td><td>unsigned long</td></tr>

2030 <tr><td>TEXTURE_WRAP_S</td><td>unsigned long</td></tr>

2031 <tr><td>TEXTURE_WRAP_T</td><td>unsigned long</td></tr>

2032 </table>

2033 <dd>

2034 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2035 <code>INVALID_OPERATION</code> error is generated.

2036 <dt class="idl-code">GLboolean isTexture(WebGLTexture texture)

2037 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.4">OpenGL ES 2.0 § 6.1.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glIsTexture.xml">man page</a>)</span>

2038 <dd>

2039 Return true if the passed WebGLTexture is valid and false otherwise.

2040 <dt class="idl-code"><a name="TEXIMAGE2D">void texImage2D</a>(GLenum tar get, GLint level, GLenum internalformat,

2041 GLsizei width, GLsizei height, GLint border, GLenum format,

2042 GLenum type, ArrayBufferView pixels)

2043 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.1">OpenGL ES 2.0 § 3.7.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glTexImage2D.xml">man page</a>)</span>

2044 <dd>

2045 If <code>pixels</code> is null, a buffer of sufficient size initiali zed to 0 is

2046 passed. <br><br>

2047

2048 If <code>pixels</code> is non-null, the type of <code>pixels</code> must match the type

2049 of the data to be read. If it is UNSIGNED_BYTE, a Uint8Array must be supplied; if it is

2050 UNSIGNED_SHORT_5_6_5, UNSIGNED_SHORT_4_4_4_4, or UNSIGNED_SHORT_5_5_ 5_1, a Uint16Array

2051 must be supplied. If the types do not match, an INVALID_OPERATION er ror is generated.

2052 <br><br>

2053

2054 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2055 <code>INVALID_OPERATION</code> error is generated. <br><br>

2056

2057 See <a href="#PIXEL_STORAGE_PARAMETERS">Pixel Storage Parameters</a> for WebGL-specific

2058 pixel storage parameters that affect the behavior of this function.

2059 <dt><p class="idl-code"><a name="TEXIMAGE2D_HTML">void texImage2D</a>(GL enum target, GLint level, GLenum internalformat,

2060 GLenum format, GLenum type, ImageData pixels)</p>

2061 <p class="idl-code">void texImage2D(GLenum target, GLint level, GLen um internalformat,

2062 GLenum format, GLenum type, HTMLImageElement image)</p>

2063 <p class="idl-code">void texImage2D(GLenum target, GLint level, GLen um internalformat,

2064 GLenum format, GLenum type, HTMLCanvasElement canvas)</p>

2065 <p class="idl-code">void texImage2D(GLenum target, GLint level, GLen um internalformat,

2066 GLenum format, GLenum type, HTMLVideoElement video)

2067 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.1">OpenGL ES 2.0 § 3.7.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glTexImage2D.xml">man page</a>)</span></p>

2068 <dd>

2069 Uploads the given element or image data to the currently bound WebGL Texture. <br><br>

2070

2071 The source image data is conceptually first converted to the data ty pe and format

2072 specified by the <em>format</em> and <em>type</em> arguments, and th en transferred to

2073 the OpenGL implementation. If a packed pixel format is specified whi ch would imply loss

2074 of bits of precision from the image data, this loss of precision mus t occur. <br><br>

2075

2076 If the source image is an RGB or RGBA lossless image with 8 bits per channel, the

2077 browser guarantees that the full precision of all channels is preser ved. <br><br>

2078

2079 If the original image contains an alpha channel and the

2080 <code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code> pixel storage parameter is false, then the

2081 RGB values are guaranteed to never have been premultiplied by the al pha channel, whether

2082 those values are derived directly from the original file format or c onverted from some

2083 other color format. <br><br>

2084

2085 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2086 <code>INVALID_OPERATION</code> error is generated. <br><br>

2087

2088 See <a href="#PIXEL_STORAGE_PARAMETERS">Pixel Storage Parameters</a> for WebGL-specific

2089 pixel storage parameters that affect the behavior of this function.

2090 <dt class="idl-code">void texParameterf(GLenum target, GLenum pname, GLf loat param)

2091 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.4">OpenGL ES 2.0 § 3.7.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glTexParameter.xml">man page</a>)</span>

2092 <dd>

2093 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2094 <code>INVALID_OPERATION</code> error is generated.

2095 <dt class="idl-code">void texParameteri(GLenum target, GLenum pname, GLi nt param)

2096 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.4">OpenGL ES 2.0 § 3.7.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glTexParameter.xml">man page</a>)</span>

2097 <dd>

2098 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2099 <code>INVALID_OPERATION</code> error is generated.

2100 <dt class="idl-code">void texSubImage2D(GLenum target, GLint level, GLin t xoffset, GLint yoffset,

2101 GLsizei width, GLsizei height,

2102 GLenum format, GLenum type, ArrayBufferView pixels)

2103 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.2">OpenGL ES 2.0 § 3.7.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glTexSubImage2D.xml">man page</a>)</span>

2104 <dd>

2105 See <a href="#TEXIMAGE2D">texImage2D</a> for restrictions on the <em >format</em>

2106 and <em>pixels</em> arguments. <br><br>

2107

2108 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2109 <code>INVALID_OPERATION</code> error is generated. <br><br>

2110

2111 See <a href="#PIXEL_STORAGE_PARAMETERS">Pixel Storage Parameters</a> for WebGL-specific

2112 pixel storage parameters that affect the behavior of this function.

2113 <dt><p class="idl-code">void texSubImage2D(GLenum target, GLint level, G Lint xoffset, GLint yoffset,

2114 GLenum format, GLenum type, ImageData pixels)</p>

2115 <p class="idl-code">void texSubImage2D(GLenum target, GLint level, G Lint xoffset, GLint yoffset,

2116 GLenum format, GLenum type, HTMLImageElement image)</p>

2117 <p class="idl-code">void texSubImage2D(GLenum target, GLint level, G Lint xoffset, GLint yoffset,

2118 GLenum format, GLenum type, HTMLCanvasElement canvas)</p>

2119 <p class="idl-code">void texSubImage2D(GLenum target, GLint level, G Lint xoffset, GLint yoffset,

2120 GLenum format, GLenum type, HTMLVideoElement video)

2121 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-3.7.2">OpenGL ES 2.0 § 3.7.2</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glTexSubImage2D.xml">man page</a>)</span></p>

2122 <dd>

2123 Updates a sub-rectangle of the currently bound WebGLTexture with the contents of the

2124 given element or image data. <br><br>

2125

2126 See <a href="#TEXIMAGE2D_HTML">texImage2D</a> for the interpretation of

2127 the <em>format</em> and <em>type</em> arguments. <br><br>

2128

2129 If an attempt is made to call this function with no WebGLTexture bou nd (see above), an

2130 <code>INVALID_OPERATION</code> error is generated. <br><br>

2131

2132 See <a href="#PIXEL_STORAGE_PARAMETERS">Pixel Storage Parameters</a> for WebGL-specific

2133 pixel storage parameters that affect the behavior of this function.

2134 </dl>

2135

2136 <!-- =========================================================================== ============================ -->

2137

2138 <h4>Programs and Shaders</h4>

2139

2140 <p>

2141 Rendering with OpenGL ES 2.0 requires the use of <i>shaders</i>, written in OpenGL ES's shading language, GLSL ES.

2142 Shaders must be loaded with a source string (shaderSource), compiled

2143 (compileShader) and attached to a <i>program</i> (attachShader) which mu st be linked

2144 (linkProgram) and then used (useProgram).

2145 </p>

2146

2147 <dl class="methods">

2148 <dt class="idl-code">void attachShader(WebGLProgram program, WebGLShader shader)

2149 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 &sect ;2.10.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glAttachShader.xml">man page</a>)</span>

2150 <dt class="idl-code">void bindAttribLocation(WebGLProgram program, GLuin t index, DOMString name)

2151 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.4">OpenGL ES 2.0 &sect ;2.10.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glBindAttribLocation.xml">man page</a>)</span>

2152 <dd>

2153 See <a href="#CHARACTERS_OUTSIDE_VALID_SET">Characters Outside the G LSL Source Character

2154 Set</a> for additional validation performed by WebGL implementations .

2155 <dt class="idl-code">void compileShader(WebGLShader shader)

2156 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.1">OpenGL ES 2.0 &sect ;2.10.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glCompileShader.xml">man page</a>)</span>

2157 <dt class="idl-code">WebGLProgram createProgram()

2158 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 &sect ;2.10.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glCreateProgram.xml">man page</a>)</span>

2159 <dd>

2160 Create a WebGLProgram object and initialize it with a program object name as if by

2161 calling glCreateProgram.

2162

2163 <dt class="idl-code">WebGLShader createShader(type)

2164 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.1">OpenGL ES 2.0 &sect ;2.10.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glCreateShader.xml">man page</a>)</span>

2165 <dd>

2166 Create a WebGLShader object and initialize it with a shader object n ame as if by

2167 calling glCreateShader.

2168

2169 <dt class="idl-code">void deleteProgram(WebGLProgram program)

2170 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 &sect ;2.10.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glDeleteProgram.xml">man page</a>)</span>

2171 <dd>

2172 Delete the program object contained in the passed WebGLProgram as if by calling

2173 glDeleteProgram. If the program has already been deleted the call ha s no effect.

2174 Note that the program object will be deleted when the WebGLProgram o bject is destroyed.

2175 This method merely gives the author greater control over when the pr ogram object is

2176 destroyed.

2177 <dt class="idl-code">void deleteShader(WebGLShader shader)

2178 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.1">OpenGL ES 2.0 &sect ;2.10.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glDeleteShader.xml">man page</a>)</span>

2179 <dd>

2180 Delete the shader object contained in the passed WebGLShader as if b y calling

2181 glDeleteShader. If the shader has already been deleted the call has no effect.

2182 Note that the shader object will be deleted when the WebGLShader obj ect is destroyed.

2183 This method merely gives the author greater control over when the sh ader object is

2184 destroyed.

2185 <dt class="idl-code">void detachShader(WebGLProgram program, WebGLShader shader)

2186 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 &sect ;2.10.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glDetachShader.xml">man page</a>)</span>

2187 <dt class="idl-code">WebGLShader[ ] getAttachedShaders(WebGLProgram prog ram)

2188 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glGetAttachedShaders.xml">man page</a>)</span>

2189 <dd>

2190 Return the list of shaders attached to the passed program.

2191 <dt class="idl-code">any getProgramParameter(WebGLProgram program, GLenu m pname)

2192 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGetProgramiv.xml">man page</a>)</span>

2193 <dd>

2194 Return the value for the passed pname given the passed program. The type returned is the natural

2195 type for the requested pname, as given in the following table:

2196 <table class="foo">

2197 <tr><th>pname</th><th>returned type</th></tr>

2198 <tr><td>DELETE_STATUS</td><td>boolean</td></tr>

2199 <tr><td>LINK_STATUS</td><td>boolean</td></tr>

2200 <tr><td>VALIDATE_STATUS</td><td>boolean</td></tr>

2201 <tr><td>ATTACHED_SHADERS</td><td>long</td></tr>

2202 <tr><td>ACTIVE_ATTRIBUTES</td><td>long</td></tr>

2203 <tr><td>ACTIVE_UNIFORMS</td><td>long</td></tr>

2204 </table>

2205 <dt class="idl-code">DOMString getProgramInfoLog(WebGLProgram program)

2206 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glGetProgramInfoLog.xml">man page</a>)</span>

2207 <dt class="idl-code">any getShaderParameter(WebGLShader shader, GLenum p name)

2208 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGetShaderiv.xml">man page</a>)</span>

2209 <dd>

2210 Return the value for the passed pname given the passed shader. The t ype returned is the natural

2211 type for the requested pname, as given in the following table:

2212 <table class="foo">

2213 <tr><th>pname</th><th>returned type</th></tr>

2214 <tr><td>SHADER_TYPE</td><td>unsigned long</td></tr>

2215 <tr><td>DELETE_STATUS</td><td>boolean</td></tr>

2216 <tr><td>COMPILE_STATUS</td><td>boolean</td></tr>

2217 </table>

2218 <dt class="idl-code">DOMString getShaderInfoLog(WebGLShader shader)

2219 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glGetShaderInfoLog.xml">man page</a>)</span>

2220 <dt class="idl-code">DOMString getShaderSource(WebGLShader shader)

2221 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glGetShaderSource.xml">man page</a>)</span>

2222 <dt class="idl-code">GLboolean isProgram(WebGLProgram program)

2223 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glIsProgram.xml">man page</a>)</span>

2224 <dd>

2225 Return true if the passed WebGLProgram is valid and false otherwise.

2226 <dt class="idl-code">GLboolean isShader(WebGLShader shader)

2227 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glIsShader.xml">man page</a>)</span>

2228 <dd>

2229 Return true if the passed WebGLShader is valid and false otherwise.

2230 <dt class="idl-code">void linkProgram(WebGLProgram program)

2231 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 &sect ;2.10.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glLinkProgram.xml">man page</a>)</span>

2232 <dt class="idl-code">void shaderSource(WebGLShader shader, DOMString sou rce)

2233 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.1">OpenGL ES 2.0 &sect ;2.10.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glShaderSource.xml">man page</a>)</span>

2234 <dd>

2235 See <a href="#SUPPORTED_GLSL_CONSTRUCTS">Supported GLSL Constructs</ a>

2236 and <a href="#CHARACTERS_OUTSIDE_VALID_SET">Characters Outside the G LSL Source Character

2237 Set</a> for additional constructs supported by and validation perfor med by WebGL

2238 implementations.

2239 <dt class="idl-code">void useProgram(WebGLProgram program)

2240 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.3">OpenGL ES 2.0 &sect ;2.10.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glUseProgram.xml">man page</a>)</span>

2241 <dt class="idl-code">void validateProgram(WebGLProgram program)

2242 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.5">OpenGL ES 2.0 &sect ;2.10.5</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glValidateProgram.xml">man page</a>)</span>

2243 </dl>

2244

2245 <!-- =========================================================================== ============================ -->

2246

2247 <h4>Uniforms and attributes</h4>

2248

2249 <p>

2250 Values used by the shaders are passed in as uniforms or vertex attribute s.

2251 </p>

2252

2253 <dl class="methods">

2254 <dt class="idl-code">void disableVertexAttribArray(GLuint index)

2255 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.8">OpenGL ES 2.0 §2. 8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glDisableVertexAttribArray.xml">man page</a>)</span>

2256 <dt class="idl-code">void enableVertexAttribArray(GLuint index)

2257 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.8">OpenGL ES 2.0 §2. 8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glEnableVertexAttribArray.xml">man page</a>)</span>

2258 <dd>

2259 Enable the vertex attribute at <code>index</code> as an array. WebGL imposes additional

2260 rules beyond OpenGL ES 2.0 regarding enabled vertex attributes;

2261 see <a href="#ATTRIBS_AND_RANGE_CHECKING">Enabled Vertex Attributes and Range

2262 Checking</a>.

2263 <dt class="idl-code">WebGLActiveInfo getActiveAttrib(WebGLProgram progra m, GLuint index)

2264 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.4">OpenGL ES 2.0 &sect ;2.10.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glGetActiveAttrib.xml">man page</a>)</span>

2265 <dd>

2266 Returns information about the size, type and name of the vertex attr ibute at the

2267 passed index of the passed program object.

2268 <dt class="idl-code">WebGLActiveInfo getActiveUniform(WebGLProgram progr am, GLuint index)

2269 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.4">OpenGL ES 2.0 &sect ;2.10.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glGetActiveUniform.xml">man page</a>)</span>

2270 <dd>

2271 Returns information about the size, type and name of the uniform at the

2272 passed index of the passed program object.

2273 <dt class="idl-code">GLint getAttribLocation(WebGLProgram program, DOMSt ring name)

2274 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.4">OpenGL ES 2.0 &sect ;2.10.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glGetAttribLocation.xml">man page</a>)</span>

2275 <dd>

2276 See <a href="#CHARACTERS_OUTSIDE_VALID_SET">Characters Outside the G LSL Source Character

2277 Set</a> for additional validation performed by WebGL implementations .

2278 <dt class="idl-code">any getUniform(WebGLProgram program, WebGLUniformLo cation location)

2279 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glGetUniform.xml">man page</a>)</span>

2280 <dd>

2281 Return the uniform value at the passed location in the passed progra m. The type returned is

2282 dependent on the uniform type, as shown in the following table:

2283 <table class="foo">

2284 <tr><th>uniform type</th><th>returned type</th></tr>

2285 <tr><td>boolean</td><td>boolean</td></tr>

2286 <tr><td>int</td><td>long</td></tr>

2287 <tr><td>float</td><td>float</td></tr>

2288 <tr><td>vec2</td><td>Float32Array (with 2 elements)</td></tr>

2289 <tr><td>ivec2</td><td>Int32Array (with 2 elements)</td></tr>

2290 <tr><td>bvec2</td><td>boolean[] (with 2 elements)</td></tr>

2291 <tr><td>vec3</td><td>Float32Array (with 3 elements)</td></tr>

2292 <tr><td>ivec3</td><td>Int32Array (with 3 elements)</td></tr>

2293 <tr><td>bvec3</td><td>boolean[] (with 3 elements)</td></tr>

2294 <tr><td>vec4</td><td>Float32Array (with 4 elements)</td></tr>

2295 <tr><td>ivec4</td><td>Int32Array (with 4 elements)</td></tr>

2296 <tr><td>bvec4</td><td>boolean[] (with 4 elements)</td></tr>

2297 <tr><td>mat2</td><td>Float32Array (with 4 elements)</td></tr>

2298 <tr><td>mat3</td><td>Float32Array (with 9 elements)</td></tr>

2299 <tr><td>mat4</td><td>Float32Array (with 16 elements)</td></tr>

2300 </table>

2301 <dt class="idl-code">WebGLUniformLocation getUniformLocation(WebGLProgra m program, DOMString name)

2302 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.4">OpenGL ES 2.0 &sect ;2.10.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glGetUniformLocation.xml">man page</a>)</span>

2303 <dd>

2304 Return a WebGLUniformLocation object that represents the location of a specific uniform variable

2305 within a program object. The return value is null if name does not c orrespond to an active uniform

2306 variable in the passed program. <br><br>

2307

2308 See <a href="#CHARACTERS_OUTSIDE_VALID_SET">Characters Outside the G LSL Source Character

2309 Set</a> for additional validation performed by WebGL implementations .

2310 <dt class="idl-code">any getVertexAttrib(GLuint index, GLenum pname)

2311 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glGetVertexAttrib.xml">man page</a>)</span>

2312 <dd>

2313 Return the information requested in pname about the vertex attribute at the passed index. The

2314 type returned is dependent on the information requested, as shown in the following table:

2315 <table class="foo">

2316 <tr><th>pname</th><th>returned type</th></tr>

2317 <tr><td>VERTEX_ATTRIB_ARRAY_BUFFER_BINDING</td><td>WebGLBuffer</ td></tr>

2318 <tr><td>VERTEX_ATTRIB_ARRAY_ENABLED</td><td>boolean</td></tr>

2319 <tr><td>VERTEX_ATTRIB_ARRAY_SIZE</td><td>long</td></tr>

2320 <tr><td>VERTEX_ATTRIB_ARRAY_STRIDE</td><td>long</td></tr>

2321 <tr><td>VERTEX_ATTRIB_ARRAY_TYPE</td><td>unsigned long</td></tr>

2322 <tr><td>VERTEX_ATTRIB_ARRAY_NORMALIZED</td><td>boolean</td></tr>

2323 <tr><td>CURRENT_VERTEX_ATTRIB</td><td>Float32Array (with 4 eleme nts)</td></tr>

2324 </table>

2325 <dt class="idl-code">GLsizeiptr getVertexAttribOffset(GLuint index, GLen um pname)

2326 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-6.1.8">OpenGL ES 2.0 § 6.1.8</a>, similar to <a class="nonnormative" href="http://www.khronos.org/openg les/sdk/2.0/docs/man/glGetVertexAttribPointerv.xml">man page</a>)</span>

2327 <dt><p class="idl-code">void uniform[1234][fi](WebGLUniformLocation loca tion, ...)</p>

2328 <p class="idl-code">void uniform[1234][fi]v(WebGLUniformLocation loc ation, ...)

2329 <p class="idl-code">void uniformMatrix[234]fv(WebGLUniformLocation l ocation, GLboolean transpose, ...)

2330 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.10.4">OpenGL ES 2.0 &sect ;2.10.4</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2 .0/docs/man/glUniform.xml">man page</a>)</span></p>

2331 <dd>

2332 Each of the uniform* functions above sets the specified uniform or u niforms to the

2333 values provided. If the passed <code>location</code> is not null and was not obtained

2334 from the currently used program via an earlier call to <code>getUnif ormLocation</code>,

2335 an <code>INVALID_OPERATION</code> error will be generated. If the pa ssed

2336 <code>location</code> is null, the data passed in will be silently i gnored and

2337 no uniform variables will be changed.

2338 <br><br>

2339 If the array passed to any of the vector forms (those ending in <cod e>v</code>) has an

2340 invalid length, an <code>INVALID_VALUE</code> error will be generate d. The length is

2341 invalid if it is too short for or is not an integer multiple of the assigned type.

2342 <dt><p class="idl-code">void vertexAttrib[1234]f(GLuint indx, ...)</p>

2343 <p class="idl-code">void vertexAttrib[1234]fv(GLuint indx, ...)

2344 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.7">OpenGL ES 2.0 §2. 7</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glVertexAttrib.xml">man page</a>)</span></p>

2345 <dd>

2346 Sets the vertex attribute at the passed index to the given constant v alue. Values set via the

2347 <code>vertexAttrib</code> are guaranteed to be returned from the <cod e>getVertexAttrib</code> function

2348 with the <code>CURRENT_VERTEX_ATTRIB</code> param, even if there have been intervening calls to

2349 <code>drawArrays</code> or <code>drawElements</code>.

2350 <dt class="idl-code">void vertexAttribPointer(GLuint indx, GLint size, GL enum type,

2351 GLboolean normalized, GLsizei stride, GLintptr offse t)

2352 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.8">OpenGL ES 2.0 §2. 8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glVertexAttribPointer.xml">man page</a>)</span>

2353 <dd>

2354 Assign the WebGLBuffer object currently bound to the ARRAY_BUFFER ta rget to the vertex

2355 attribute at the passed index. Size is number of components per attr ibute. Stride and

2356 offset are in units of bytes. Passed stride and offset must be appro priate for the

2357 passed type and size or an <code>INVALID_OPERATION</code> error will be

2358 generated; see <a href="#BUFFER_OFFSET_AND_STRIDE">Buffer Offset and Stride

2359 Requirements</a>. If no WebGLBuffer is bound to the ARRAY_BUFFER tar get,

2360 an <code>INVALID_OPERATION</code> error will be generated. In WebGL, the maximum

2361 supported stride is 255; see <a href="#VERTEX_STRIDE"> Vertex Attrib ute Data Stride</a>.

2362 </dl>

2363

2364 <!-- =========================================================================== ============================ -->

2365

2366 <h4>Writing to the drawing buffer</h4>

2367

2368 <p>

2369 OpenGL ES 2.0 has 3 calls which can render to the drawing buffer: <code> clear</code>,

2370 <code>drawArrays</code> and <code>drawElements</code>. Furthermore rende ring can

2371 be directed to the drawing buffer or to a Framebuffer object. When rende ring is

2372 directed to the drawing buffer, making any of the 3 rendering calls shal l

2373 cause the drawing buffer to be presented to the HTML page compositor at the start

2374 of the next compositing operation.

2375 </p>

2376

2377 <dl class="methods">

2378 <dt class="idl-code">void clear(GLbitfield mask)

2379 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.2.3">OpenGL ES 2.0 § 4.2.3</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glClear.xml">man page</a>)</span>

2380 <dt class="idl-code">void drawArrays(GLenum mode, GLint first, GLsizei c ount)

2381 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.8">OpenGL ES 2.0 §2. 8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glDrawArrays.xml">man page</a>)</span>

2382 <dd>

2383 If <em>first</em> is negative, an <code>INVALID_VALUE</code> error w ill be generated.

2384 <dt class="idl-code">void drawElements(GLenum mode, GLsizei count, GLenu m type, GLintptr offset)

2385 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-2.8">OpenGL ES 2.0 §2. 8</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glDrawElements.xml">man page</a>)</span>

2386 <dd>

2387 Draw using the currently bound element array buffer. The given offs et is in bytes, and

2388 must be a valid multiple of the size of the given type or an <code>I NVALID_OPERATION</code>

2389 error will be generated; see <a href="#BUFFER_OFFSET_AND_STRIDE">Buf fer Offset and Stride

2390 Requirements</a>. If <code>count</code> is greater than zero, then a non-null

2391 <code>WebGLBuffer</code> must be bound to the <code>ELEMENT_ARRAY_BU FFER</code> binding

2392 point or an <code>INVALID_OPERATION</code> error will be generated.< br><br>

2393

2394 WebGL performs additional error checking beyond that specified in Op enGL ES 2.0 during

2395 calls to <code>drawArrays</code>

2396 and <code>drawElements</code>. See <a href="#ATTRIBS_AND_RANGE_CHECK ING">Enabled Vertex

2397 Attributes and Range Checking</a>.

2398 <dt class="idl-code">void finish()

2399 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-5.1">OpenGL ES 2.0 §5. 1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glFinish.xml">man page</a>)</span>

2400 <dt class="idl-code">void flush()

2401 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-5.1">OpenGL ES 2.0 §5. 1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0/doc s/man/glFlush.xml">man page</a>)</span>

2402 </dl>

2403

2404 <!-- =========================================================================== ============================ -->

2405

2406 <h4><a name="readpixels">Reading back pixels</a></h4>

2407

2408 <p>

2409 Pixels in the current framebuffer can be read back into an ArrayBufferVi ew object.

2410 </p>

2411

2412 <dl class="methods">

2413 <dt class="idl-code">void readPixels(GLint x, GLint y, GLsizei width, GL sizei height,

2414 GLenum format, GLenum type, ArrayBufferView pixels)

2415 <span class="gl-spec">(<a href="http://www.khronos.org/registry/gles /specs/2.0/es_full_spec_2.0.24.pdf#nameddest=section-4.3.1">OpenGL ES 2.0 § 4.3.1</a>, <a class="nonnormative" href="http://www.khronos.org/opengles/sdk/2.0 /docs/man/glReadPixels.xml">man page</a>)</span>

2416 <dd>

2417 Fills <code>pixels</code> with the pixel data in the specified recta ngle of the frame

2418 buffer. The data returned from readPixels must be up-to-date as of t he most recently

2419 sent drawing command.

2420 <br><br>

2421

2422 The type of <code>pixels</code> must match the type of the data to b e read. For example,

2423 if it is UNSIGNED_BYTE, a Uint8Array must be supplied; if it is UNSI GNED_SHORT_5_6_5,

2424 UNSIGNED_SHORT_4_4_4_4, or UNSIGNED_SHORT_5_5_5_1, a Uint16Array mus t be supplied. If

2425 the types do not match, an INVALID_OPERATION error is generated.

2426 <br><br>

2427

2428 The following are the allowed format and type combinations:

2429

2430 <table class="foo">

2431 <tr><th>format</th><th>type</th></tr>

2432 <tr><td>RGBA</td><td>UNSIGNED_BYTE</td></tr>

2433 </table>

2434

2435 If <code>pixels</code> is null, an INVALID_VALUE error is generated. If

2436 <code>pixels</code> is non-null, but is not large enough to retrieve all of the pixels

2437 in the specified rectangle taking into account pixel store modes, an INVALID_OPERATION

2438 value is generated.

2439 <br><br>

2440

2441 For any pixel lying outside the frame buffer, the value read contain s 0 in all channels;

2442 see <a href="#READS_OUTSIDE_FRAMEBUFFER">Reading Pixels Outside the Framebuffer</a>.

2443 <br><br>

2444

2445 </dl>

2446

2447 <!-- =========================================================================== ============================ -->

2448

2449 <h4>Detecting context lost events</h4>

2450

2451 <p>

2452 Occurrences such as power events on mobile devices may cause the WebGL r endering context to

2453 be lost at any time and require the application to rebuild it;

2454 see <a href="#WEBGLCONTEXTEVENT">WebGLContextEvent</a> for more details. The

2455 following method assists in detecting context lost events.

2456 </p>

2457

2458 <dl class="methods">

2459 <dt class="idl-code">boolean isContextLost()

2460 <dd>

2461 Returns true if the context is in the lost state.

2462 </dl>

2463

2464 <!-- =========================================================================== ============================ -->

2465

2466 <h4>Detecting and enabling extensions</h4>

2467

2468 <p>

2469 An implementation of WebGL must not support any additional parameters, c onstants or functions

2470 without first enabling that functionality through the extension mechanis m. The

2471 <code>getSupportedExtensions</code> function returns an array of the ext ension strings supported

2472 by this implementation. Extension strings are case-insensitive. An exten sion is enabled by

2473 passing one of those strings to the <code>getExtension</code> function. This call returns an

2474 object which contains any constants or functions defined by that extensi on. The definition of

2475 that object is specific to the extension and must be defined by the exte nsion specification.

2476 </p>

2477 <p>

2478 Once an extension is enabled, no mechanism is provided to disable it. Mu ltiple calls to

2479 <code>getExtension</code> with the same extension string shall return th e same object. An

2480 attempt to use any features of an extension without first calling getExt ension to enable it

2481 must generate an appropriate GL error and must not make use of the featu re.

2482 </p>

2483 <p>

2484 This specification does not define any extensions. A separate <a href="# refsREGISTRY">WebGL

2485 extension registry</a> defines extensions that may be supported by a par ticular WebGL

2486 implementation.

2487 </p>

2488

2489 <dl class="methods">

2490 <dt class="idl-code">DOMString[ ] getSupportedExtensions()

2491 <dd>

2492 Returns an array of all the supported extension strings. Any string in this list, when

2493 passed to <code>getExtension</code> must return a valid object. Any other string passed to

2494 <code>getExtension</code> must return null.

2495

2496 <dt class="idl-code">object getExtension(DOMString name)

2497 <dd>

2498 Returns an object if the passed extension is supported, or null if n ot. The object

2499 returned from <code>getExtension</code> contains any constants or fu nctions used by the

2500 extension, if any. A returned object may have no constants or functi ons if the extension does

2501 not define any, but a unique object must still be returned. That obj ect is used to indicate

2502 that the extension has been enabled.

2503 </dl>

2504

2505 <!-- =========================================================================== ============================ -->

2506

2507 <h3><a name="WEBGLCONTEXTEVENT">WebGLContextEvent</a></h3>

2508

2509 <p>

2510 WebGL generates a WebGLContextEvent event in response to a status change to the WebGL rendering context

2511 associated with the HTMLCanvasElement which has a listener for this even t. Events are sent using

2512 the <a href="http://www.w3.org/TR/DOM-Level-2-Events/events.html">DOM Ev ent System</a>. Event types can

2513 include the loss or restoration of state, or the inability to create a c ontext.

2514 </p>

2515 <pre class="idl">

2516 interface <dfn id="WebGLContextLostEvent">WebGLContextEvent</dfn> : Event {

2517 readonly attribute DOMString statusMessage;

2518

2519 void initWebGLContextEvent(DOMString typeArg,

2520 boolean canBubbleArg,

2521 boolean cancelableArg,

2522 DOMString statusMessageArg);

2523 };</pre>

2524

2525 <h4>Attributes</h4>

2526

2527 <p>

2528 The following attributes are available:

2529 </p>

2530

2531 <dl class="methods">

2532 <dt><span class="prop-name"><code>statusMessage</code></span> of type <c ode>DOMString</code>

2533 <dd>

2534 A string containing additional information, or the empty string if n o additional information

2535 is available.

2536 </dl>

2537

2538 <h4>Methods</h4>

2539

2540 <p>

2541 The following methods are available:

2542 </p>

2543

2544 <dl class="methods">

2545 <dt class="idl-code">void initWebGLContextEvent(DOMString typeArg, boole an canBubbleArg, boolean cancelableArg,

2546 DOMString statusMessageA rg)

2547 <dd>

2548 Initialize the event created through the

2549 <a href="http://www.w3.org/TR/DOM-Level-2-Events/events.html#Events- Event">Event</a>

2550 interface. This method may only be called before the event has been dispatched via

2551 the <code>dispatchEvent</code> method, though it may be called multi ple times during

2552 that phase if necessary. If called multiple times, the final invocat ion takes

2553 precedence.

2554 <P>

2555 <b>Parameters</b>

2556 <dl>

2557 <dt><code>typeArg</code> of type <code>DOMString</code>

2558 <dd>Specifies the event type (see below).

2559 <dt><code>canBubbleArg</code> of type <code>boolean</code>

2560 <dd>Specifies whether or not the event can bubble.

2561 <dt><code>cancelableArg</code> of type <code>boolean</code>

2562 <dd>Specifies whether or not the event can be canceled.

2563 <dt><code>statusMessageArg</code> of type <code>DOMString</code>

2564 <dd>A string containing additional information, or the empty str ing if no additional information is available.

2565 </dl>

2566 <b>No Return Value</b><br>

2567 <b>No Exceptions</b><br>

2568 </dl>

2569

2570 <h4>Event Types</h4>

2571

2572 <dl class="methods">

2573 <dt class="idl-code">webglcontextlost

2574 <dd>

2575 This event occurs when some system activity external to WebGL causes the rendering context

2576 associated with the HTMLCanvasElement receiving the event to lose al l of its state. When this

2577 event type is delivered, the associated context is in a "lost" state . While the context is

2578 in the lost state:

2579

2580 <ul>

2581 <li> The context's <code>isContextLost</code> method returns <code>true< /code>.<br>

2582 <li> All methods returning <code>void</code> return immediately.<br>

2583 <li> All methods returning nullable values or <code>any</code> return <c ode>null</code>.<br>

2584 <li> <code>checkFramebufferStatus</code> returns <code>FRAMEBUFFER_UNSUP PORTED</code>.<br>

2585 <li> <code>getAttribLocation</code> returns <code>-1</code>.<br>

2586 <li> <code>getError</code> returns <code>CONTEXT_LOST_WEBGL</code> the f irst time it is

2587 called while the context is lost. Afterward it will return <code>NO _ERROR</code> until

2588 the context has been restored.<br>

2589 <li> <code>getVertexAttribOffset</code> returns <code>0</code>.<br>

2590 <li> All <code>is</code> queries return <code>false</code>.<br>

2591 </ul>

2592 <p>

2593 See the <code>webglcontextrestored</code> event type for information on

2594 resuming rendering after the context has been lost.

2595 <p><p>

2596 The <code>statusMessage</code> attribute is always the empty string for this event.

2597 </dl>

2598

2599 <dl class="methods">

2600 <dt class="idl-code">webglcontextrestored

2601 <dd>

2602 This event occurs when the WebGL implementation determines that a pr eviously lost context can

2603 be restored. The system only restores the context if a handler for t he

2604 <code>webglcontextrestored</code> event is installed on the HTMLCanv asElement associated with

2605 the context.

2606 <p><p>

2607 Once the context is restored, WebGL resources such as textures and b uffers that were created

2608 before the context was lost are no longer valid. The application mus t reinitialize the

2609 context's state and recreate all such resources.

2610 <p><p>

2611 The <code>statusMessage</code> attribute is always the empty string for this event.

2612 </dl>

2613

2614 <dl class="methods">

2615 <dt class="idl-code">webglcontextcreationerror

2616 <dd>

2617 This event occurs in response to a call to <code>getContext()</code> on the HTMLCanvasElement

2618 receiving the event, when some error occurs during that call. When s uch an error occurs

2619 the <code>getContext()</code> returns with a <code>null</code> value . Later, at the normal

2620 event delivery time, this event is delivered with the details of the failure. If the

2621 HTMLCanvasElement is listening for this event, it will be delivered whenever

2622 <code>getContext()</code> returns <code>null</code>.

2623 <p>

2624 The <code>statusMessage</code> attribute may contain a platform depe ndent string about the nature

2625 of the failure.

2626 </dl>

2627

2628 <div class="example">

2629 The following ECMAScript example shows how to register event listeners on a Canvas called

2630 <code>canvas1</code> which will receive context lost and restored events and restart the

2631 application. For completeness, it illustrates how an application performing asynchronous image

2632 loading would handle a context lost event at an arbitrary point in time.

2633 <pre>

2634 window.onload = init;

2635

2636 var g_gl;

2637 var g_canvas;

2638 var g_intervalId;

2639 var g_images = [];

2640 var g_imgURLs = [

2641 "someimage.jpg",

2642 "someotherimage.jpg",

2643 "yetanotherimage.png"

2644 ];

2645

2646 function init() {

2647 g_canvas = document.getElementById("canvas1");

2648 g_canvas.addEventListener("webglcontextlost", contextLostHandler, false);

2649 g_canvas.addEventListener("webglcontextrestored", contextRestoredHandler, fals e);

2650 g_gl = canvas.getContext("webgl");

2651

2652 for (var ii = 0; ii < g_imgURLs.length; ++ii) {

2653 // Create an image tag.

2654 var image = document.createElement('img');

2655

2656 // Create a texture for this image.

2657 image.texture = g_gl.createTexture();

2658

2659 // Mark the image as not loaded.

2660 image.loaded = false;

2661

2662 // Setup a load callback.

2663 image.onload = (function(image) {

2664 return function() {

2665 imageLoadedHandler(image);

2666 };

2667 }(image));

2668

2669 // Start the image loading.

2670 image.src = g_imgURLs[ii];

2671

2672 // Remember the image.

2673 g_images.push(image);

2674 }

2675

2676 g_intervalId = window.setInterval(renderHandler, 1000/60);

2677 }

2678

2679 function renderHandler() {

2680 // draw with textures.

2681 // ...

2682 }

2683

2684 function imageLoadedHandler(image) {

2685 // Mark the image as loaded.

2686 image.loaded = true;

2687

2688 // Copy the image to the texture.

2689 updateTexture(image);

2690 }

2691

2692 function updateTexture(image) {

2693 if (!g_gl.isContextLost() && image.loaded) {

2694 g_gl.bindTexture(g_gl.TEXTURE_2D, image.texture);

2695 g_gl.texImage2D(g_gl.TEXTURE_2D, 0, image);

2696 }

2697 }

2698

2699 function contextLostHandler() {

2700 // stop rendering.

2701 window.clearInterval(g_internvalId);

2702 }

2703

2704 function contextRestoredHandler() {

2705 // create new textures for all images and restore their contents.

2706 for (var ii = 0; ii < g_images.length; ++ii) {

2707 g_images[ii].texture = g_gl.createTexture();

2708 updateTexture(g_images[ii]);

2709 }

2710

2711 // Start rendering again.

2712 g_intervalId = window.setInterval(renderHandler, 1000/60);

2713 }

2714 </pre>

2715 </div>

2716

2717 <!-- =========================================================================== ============================ -->

2718

2719 <h2><a name="webgl_gl_differences">Differences Between WebGL and OpenGL ES 2 .0</a></h2>

2720

2721 <p>

2722

2723 This section describes changes made to the WebGL API relative to the OpenGL ES 2 .0 API to improve

2724 portability across various operating systems and devices.

2725

2726 </p>

2727

2728 <h3>Buffer Object Binding</h3>

2729

2730 <p>

2731

2732 In the WebGL API, a given buffer object may only be bound to one of the <code>AR RAY_BUFFER</code> or

2733 <code>ELEMENT_ARRAY_BUFFER</code> binding points in its lifetime. This restricti on implies that a

2734 given buffer object may contain either vertices or indices, but not both.

2735

2736 </p>

2737 <p>

2738

2739 The type of a WebGLBuffer is initialized the first time it is passed as an argum ent

2740 to <code>bindBuffer</code>. A subsequent call to <code>bindBuffer</code> which a ttempts to bind the

2741 same WebGLBuffer to the other binding point will generate an <code>INVALID_OPERA TION</code> error, and

2742 the state of the binding point will remain untouched.

2743

2744 </p>

2745

2746 <h3>No Client Side Arrays</h3>

2747

2748 <p>

2749

2750 The WebGL API does not support client-side arrays. If <code>vertexAttribPointer< /code> is called

2751 without a <code>WebGLBuffer</code> bound to the <code>ARRAY_BUFFER</code> bindin g point,

2752 an <code>INVALID_OPERATION</code> error is generated. If <code>drawElements</cod e> is called with

2753 a <code>count</code> greater than zero, and no <code>WebGLBuffer</code> is bound to

2754 the <code>ELEMENT_ARRAY_BUFFER</code> binding point, an <code>INVALID_OPERATION< /code> error is

2755 generated.

2756

2757 </p>

2758

2759 <h3><a name="BUFFER_OFFSET_AND_STRIDE">Buffer Offset and Stride Requirements </a></h3>

2760

2761 <p>

2762

2763 The <code>offset</code> arguments to <code>drawElements</code> and <code>vertexA ttribPointer</code>,

2764 and the <code>stride</code> argument to <code>vertexAttribPointer</code>, must b e a multiple of the

2765 size of the data type passed to the call, or an <code>INVALID_OPERATION</code> e rror is generated.

2766

2767 </p>

2768

2769

2770 <h3><a name="ATTRIBS_AND_RANGE_CHECKING">Enabled Vertex Attributes and Range Checking</a></h3>

2771

2772 <p>

2773

2774 If a vertex attribute is enabled as an array via <code>enableVertexAttribArray</ code> but no buffer

2775 is bound to that attribute via <code>bindBuffer</code> and <code>vertexAttribPoi nter</code>, then

2776 calls to <code>drawArrays</code> or <code>drawElements</code> will generate an

2777 <code>INVALID_OPERATION</code> error.

2778

2779 </p>

2780 <p>

2781

2782 If a vertex attribute is enabled as an array, a buffer is bound to that attribut e, and the attribute

2783 is consumed by the current program, then calls to <code>drawArrays</code>

2784 and <code>drawElements</code> will verify that each referenced vertex lies withi n the storage of the

2785 bound buffer. If the range specified in <code>drawArrays</code> or any reference d index

2786 in <code>drawElements</code> lies outside the storage of the bound buffer, an IN VALID_OPERATION

2787 error is generated and no geometry is drawn.

2788

2789 </p>

2790 <p>

2791

2792 If a vertex attribute is enabled as an array, a buffer is bound to that attribut e, but the attribute

2793 is not consumed by the current program, then regardless of the size of the bound buffer, it will not

2794 cause any error to be generated during a call to <code>drawArrays</code>

2795 or <code>drawElements</code>.

2796

2797 </p>

2798

2799 <h3>Framebuffer Object Attachments</h3>

2800

2801 <p>

2802

2803 WebGL adds the <code>DEPTH_STENCIL_ATTACHMENT</code> framebuffer object attachme nt point and

2804 the <code>DEPTH_STENCIL</code> renderbuffer internal format. To attach both dept h and stencil

2805 buffers to a framebuffer object, call <code>renderbufferStorage</code> with

2806 the <code>DEPTH_STENCIL</code> internal format, and then call <code>framebufferR enderbuffer</code>

2807 with the <code>DEPTH_STENCIL_ATTACHMENT</code> attachment point.

2808

2809 </p>

2810 <p>

2811

2812 A renderbuffer attached to the <code>DEPTH_ATTACHMENT</code> attachment point mu st be allocated with

2813 the <code>DEPTH_COMPONENT16</code> internal format. A renderbuffer attached to

2814 the <code>STENCIL_ATTACHMENT</code> attachment point must be allocated with

2815 the <code>STENCIL_INDEX8</code> internal format. A renderbuffer attached to

2816 the <code>DEPTH_STENCIL_ATTACHMENT</code> attachment point must be allocated wit h

2817 the <code>DEPTH_STENCIL</code> internal format.

2818

2819 </p>

2820 <p>

2821

2822 In the WebGL API, it is an error to concurrently attach renderbuffers to the fol lowing combinations

2823 of attachment points:

2824

2825 <ul>

2826 <li> <code>DEPTH_ATTACHMENT + DEPTH_STENCIL_ATTACHMENT</code>

2827 <li> <code>STENCIL_ATTACHMENT + DEPTH_STENCIL_ATTACHMENT</code>

2828 <li> <code>DEPTH_ATTACHMENT + STENCIL_ATTACHMENT</code>

2829 </ul>

2830

2831 If any of the constraints above are violated, then:

2832

2833 <ul>

2834 <li> <code>checkFramebufferStatus</code> must return <code>FRAMEBUFFER_UNSUPPORT ED</code>.

2835 <li> The following calls, which either modify or read the framebuffer, must gene rate

2836 an <code>INVALID_FRAMEBUFFER_OPERATION</code> error and return early, leavi ng the contents of

2837 the framebuffer, destination texture or destination memory untouched.

2838 <ul>

2839 <li> clear

2840 <li> copyTexImage2D

2841 <li> copyTexSubImage2D

2842 <li> drawArrays

2843 <li> drawElements

2844 <li> readPixels

2845 </ul>

2846 </ul>

2847

2848 <h3><a name="PIXEL_STORAGE_PARAMETERS">Pixel Storage Parameters</a></h3>

2849

2850 <p>

2851 The WebGL API supports the following additional parameters to <code>pixelStorei< /code>.

2852

2853 <dl>

2854 <dt><code>UNPACK_FLIP_Y_WEBGL</code> of type <code>boolean</code>

2855 <dd>If set, then during any subsequent calls to <code>texImage2D</code> or

2856 <code>texSubImage2D</code>, the source data is flipped along the vertical axis, so that conceptually

2857 the last row is the first one transferred. The default value is <code>false</cod e>. Any non-zero

2858 value is interpreted as <code>true</code>.

2859

2860 <dt><code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code> of type <code>boolean</code>

2861 <dd>If set, then during any subsequent calls to <code>texImage2D</code>

2862 or <code>texSubImage2D</code>, the alpha channel of the source data, if present, is multiplied into

2863 the color channels during the data transfer. The default value is <code>false</c ode>. Any non-zero

2864 value is interpreted as <code>true</code>.

2865

2866 <dt><code>UNPACK_COLORSPACE_CONVERSION_WEBGL</code> of type <code>unsigned long< /code>

2867 <dd>If set to <code>BROWSER_DEFAULT_WEBGL</code>, then the browser's default col orspace conversion

2868 is applied during subsequent <code>texImage2D</code> and <code>texSubImage2D</co de> calls

2869 taking <code>HTMLImageElement</code>. The precise conversions may be specific to both the browser

2870 and file type. If set to <code>NONE</code>, no colorspace conversion is applied. The default value

2871 is <code>BROWSER_DEFAULT_WEBGL</code>.

2872

2873 </dl>

2874

2875 <h3><a name="READS_OUTSIDE_FRAMEBUFFER">Reading Pixels Outside the Framebuffer</ a></h3>

2876

2877 <p>

2878 In the WebGL API, functions which read the framebuffer

2879 (<code>copyTexImage2D</code>, <code>copyTexSubImage2D</code>, and <code>readPixe ls</code>) are

2880 defined to generate the RGBA value (0, 0, 0, 0) for any pixel which is outside o f the bound

2881 framebuffer.

2882 </p>

2883

2884 <h3><a name="STENCIL_SEPARATE_LIMIT">Stencil Separate Mask and Reference Value</ a></h3>

2885

2886 <p>

2887 In the WebGL API it is illegal to specify a different mask or reference value fo r front facing and

2888 back facing triangles in stencil operations. A call to <code>drawArrays</code>

2889 or <code>drawElements</code> will generate an <code>INVALID_OPERATION</code> err or if:

2890

2891 <ul>

2892 <li> <code>STENCIL_WRITEMASK</code> != <code>STENCIL_BACK_WRITEMASK</code> (as s pecified by <code>stencilMaskSeparate</code> for the <code>mask</code> parameter associated with the FRONT and BACK values of <code>face</code>, respectively)

2893 <li> <code>STENCIL_VALUE_MASK</code> != <code>STENCIL_BACK_VALUE_MASK</code> (as specified by <code>stencilFuncSeparate</code> for the <code>mask</code> paramet er associated with the FRONT and BACK values of <code>face</code>, respectively)

2894 <li> <code>STENCIL_REF</code> != <code>STENCIL_BACK_REF</code> (as specified by <code>stencilFuncSeparate</code> for the <code>ref</code> parameter associated w ith the FRONT and BACK values of <code>face</code>, respectively)

2895 </ul>

2896

2897 </p>

2898

2899 <h3><a name="VERTEX_STRIDE">Vertex Attribute Data Stride</a></h3>

2900

2901 <p>

2902 The WebGL API supports vertex attribute data strides up to 255 bytes. A call to

2903 <code>vertexAttribPointer</code> will generate an <code>INVALID_VALUE</code> err or if the value for

2904 the stride parameter exceeds 255.

2905 </p>

2906

2907 <h3><a name="VIEWPORT_DEPTH_RANGE">Viewport Depth Range</a></h3>

2908

2909 <p>

2910 The WebGL API does not support depth ranges with where the near plane is mapped to a value greater

2911 than that of the far plane. A call to <code>depthRange</code> will generate an

2912 <code>INVALID_OPERATION</code> error if <code>zNear</code> is greater than <code >zFar</code>.

2913 </p>

2914

2915 <h3><a name="CONSTANT_COLOR_BLEND">Blending With Constant Color</a></h3>

2916

2917 <p>

2918 In the WebGL API, constant color and constant alpha cannot be used together as s ource and

2919 destination factors in the blend function. A call to <code>blendFunc</code> will generate an

2920 <code>INVALID_OPERATION</code> error if one of the two factors is set to <code>C ONSTANT_COLOR</code>

2921 or <code>ONE_MINUS_CONSTANT_COLOR</code> and the other to <code>CONSTANT_ALPHA</ code> or

2922 <code>ONE_MINUS_CONSTANT_ALPHA</code>. A call to <code>blendFuncSeparate</code> will generate an

2923 <code>INVALID_OPERATION</code> error if <code>srcRGB</code> is set to <code>CONS TANT_COLOR</code>

2924 or <code>ONE_MINUS_CONSTANT_COLOR</code> and <code>dstRGB</code> is set to <code >CONSTANT_ALPHA</code> or

2925 <code>ONE_MINUS_CONSTANT_ALPHA</code> or vice versa.

2926 </p>

2927

2928 <h3>Fixed point support</h3>

2929

2930 The WebGL API does not support the <code>GL_FIXED</code> data type.

2931

2932 <h3>GLSL Constructs</h3>

2933

2934 <p>

2935 Per <a href="#SUPPORTED_GLSL_CONSTRUCTS">Supported GLSL Constructs</a>, identifi ers starting with

2936 "webgl_" and "_webgl_" are reserved for use by WebGL.

2937 </p>

2938

2939 <h3><a name="EXTENSION_QUERIES">Extension Queries</a></h3>

2940

2941 <p>

2942

2943 In the OpenGL ES 2.0 API, the available extensions are determined by calling

2944 <code>glGetString(GL_EXTENSIONS)</code>, which returns a space-separated list of extension strings.

2945 In the WebGL API, the <code>EXTENSIONS</code> enumerant has been removed.

2946 Instead, <code>getSupportedExtensions</code> must be called to determine the set of available

2947 extensions.

2948

2949 </p>

2950

2951 <h3><a name="IMPLEMENTATION_READ_FORMAT">Implementation Color Read Format an d Type</a></h3>

2952

2953 <p>

2954

2955 In the OpenGL ES 2.0 API, the

2956 <code>IMPLEMENTATION_COLOR_READ_FORMAT</code> and

2957 <code>IMPLEMENTATION_COLOR_READ_TYPE</code> parameters are used to inform ap plications of an

2958 additional format and type combination that may be passed to <code>ReadPixel s</code>, in

2959 addition to the required <ncode>RGBA</code>/<code>UNSIGNED_BYTE</code> pair. In WebGL 1.0,

2960 the supported format and type combinations to <code>ReadPixels</code> are do cumented in the

2961 <a href="#readpixels">Reading back pixels</a> section. The <code>IMPLEMENTA TION_COLOR_READ_FORMAT</code>

2962 and <code>IMPLEMENTATION_COLOR_READ_TYPE</code> enumerants have been removed .

2963 </p>

2964

2965 <h3><a name="COMPRESSED_TEXTURE_SUPPORT">Compressed Texture Support</a></h3>

2966

2967 <p>

2968 WebGL does not support any compressed texture formats. Therefore the <code>C ompressedTexImage2D</code>

2969 and <code>CompressedTexSubImage2D</code> functions are not included in this specification.

2970 Likewise the <code>COMPRESSED_TEXTURE_FORMATS</code> and <code>NUM_COMPRESSE D_TEXTURE_FORMATS</code>

2971 parameters to <code>getParameter</code> will return the value null or zero.

2972 </p>

2973

2974 <h3><a name="MAX_GLSL_IDENTIFIER_NAME">Maximum GLSL Identifier Name Limit</a ></h3>

2975

2976 <p>

2977 The GLSL ES spec <a href="#refsGLES20GLSL">[GLES20GLSL]</a> does not define a limit to the length

2978 of identifier names. WebGL requires support of identifier names of at least 256 characters in length.

2979 </p>

2980

2981 <h3><a name="CHARACTERS_OUTSIDE_VALID_SET">Characters Outside the GLSL Sourc e Character Set</a></h3>

2982

2983 <p>

2984 The GLSL ES spec <a href="#refsGLES20GLSL">[GLES20GLSL]</a> defines the sour ce character set for

2985 the OpenGL ES shading language to be ISO/IEC 646:1991, commonly called ASCII <a href="#refsASCII">[ASCII]</a>.

2986 If a string containing a character not in this set is passed to any of the s hader-related entry

2987 points <code>bindAttribLocation</code>, <code>getAttribLocation</code>, <cod e>getUniformLocation</code>,

2988 or <code>shaderSource</code>, an <code>INVALID_VALUE</code> error will be ge nerated. The exception is

2989 that any character allowed in an HTML DOMString <a href="#refsDOMSTRING">[DO MSTRING]</a> may be used

2990 in GLSL comments. Such use must not generate an error.

2991 </p>

2992

2993 <div class="note">

2994 <p>

2995 Some GLSL implementations disallow characters outside the ASCII range, e ven in comments. In such

2996 cases the WebGL implementation needs to prevent errors in such cases. Th e recommended technique

2997 is to preprocess the GLSL string, removing all comments, but maintaining the line numbering by

2998 inserting newline characters as needed for debugging purposes.

2999 </p>

3000 </div>

3001

3002 <h3>String Length Queries</h3>

3003

3004 <p>

3005 In the WebGL API, the enumerants <code>INFO_LOG_LENGTH</code>, <code>SHADER_ SOURCE_LENGTH</code>,

3006 <code>ACTIVE_UNIFORM_MAX_LENGTH</code>, and <code>ACTIVE_ATTRIB_MAX_LENGTH</ code> have been removed. In

3007 the OpenGL ES 2.0 API, these enumerants are needed to determine the size of buffers passed to calls

3008 like <code>glGetActiveAttrib</code>. In the WebGL API, the analogous calls ( <code>getActiveAttrib</code>,

3009 <code>getActiveUniform</code>, <code>getProgramInfoLog</code>, <code>getShad erInfoLog</code>, and

3010 <code>getShaderSource</code>) all return <code>DOMString</code>.

3011 </p>

3012

3013 <!-- =========================================================================== ============================ -->

3014

3015 <h2>References</h2>

3016

3017 <h3>Normative references</h3>

3018 <dl>

3019

3020 <dt id="refsCANVAS">[CANVAS]</dt>

3021 <dd><cite><a href="http://www.w3.org/TR/html5/the-canvas-element.html">

3022 HTML5: The Canvas Element</a></cite>,

3023 World Wide Web Consortium (W3C).

3024 </dd>

3025 <dt id="refsTYPEDARRAYS">[TYPEDARRAYS]</dt>

3026 <dd><cite><a href="http://www.khronos.org/registry/typedarray/specs/1.0/ ">

3027 Typed Array Specification: Version 1.0</a></cite>,

3028 V. Vukicevic, K. Russell, February 2011.

3029 </dd>

3030 <dt id="refsGLES20">[GLES20]</dt>

3031 <dd><cite><a href="http://www.khronos.org/registry/gles/specs/2.0/es_ful l_spec_2.0.25.pdf">

3032 OpenGL® ES Common Profile Specification Version 2.0.25</a></cite >,

3033 A. Munshi, J. Leech, November 2010.

3034 </dd>

3035 <dt id="refsGLES20GLSL">[GLES20GLSL]</dt>

3036 <dd><cite><a href="http://www.khronos.org/registry/gles/specs/2.0/GLSL_E S_Specification_1.0.17.pdf">

3037 The OpenGL® ES Shading Language Version 1.00</a></cite>,

3038 R. Simpson, May 2009.

3039 </dd>

3040 <dt id="refsREGISTRY">[REGISTRY]</dt>

3041 <dd><cite><a href="http://www.khronos.org/registry/webgl/extensions/">

3042 WebGL Extension Registry</a></cite>

3043 </dd>

3044 <dt id="refsRFC2119">[RFC2119]</dt>

3045 <dd><cite><a href="http://www.ietf.org/rfc/rfc2119.txt">

3046 Key words for use in RFCs to Indicate Requirement Levels</a></cite>,

3047 S. Bradner. IETF, March 1997.

3048 </dd>

3049 <dt id="refsWEBIDL">[WEBIDL]</dt>

3050 <dd><cite><a href="http://dev.w3.org/2006/webapi/WebIDL/">

3051 Web IDL: W3C Editor’s Draft</a></cite>,

3052 C. McCormack, September 2009.

3053 </dd>

3054 <dt id="refsASCII">[ASCII]</dt>

3055 <dd><cite>International Standard ISO/IEC 646:1991. Information technolog y -

3056 ISO 7-bit coded character set for information interchange</cite>

3057 </dd>

3058 <dt id="refsDOMSTRING">[DOMSTRING]</dt>

3059 <dd><cite><a href="http://www.w3.org/TR/DOM-Level-2-Core/core.html#DOMSt ring">

3060 Document Object Model Core: The DOMString type</a></cite>,

3061 World Wide Web Consortium (W3C).

3062 </dd>

3063 </dl>

3064

3065 <h3>Other references</h3>

3066

3067 <!-- =========================================================================== ============================ -->

3068

3069 <h2>Acknowledgments</h2>

3070 <p>This specification is produced by the Khronos WebGL Working Group.</p>

3071

3072 <p>

3073 Special thanks to: Arun Ranganathan (Mozilla), Jon Leech, Kenneth Russell (Google),

3074 Kenneth Waters (Google), Mark Callow (HI), Mark Steele (Mozilla), Oliver Hunt (Apple),

3075 Tim Johansson (Opera), Vangelis Kokkevis (Google), Vladimir Vukicevic (Mo zilla),

3076 Gregg Tavares (Google)

3077 </p>

3078 <p>

3079 Additional thanks to: Alan Hudson (Yumetech), Bill Licea Kane (AMD), Ced ric Vivier (Zegami),

3080 Dan Gessel (Apple), David Ligon (Qualcomm), Greg Ross (Nvidia), Jacob St rom (Ericsson), Kari Pulli (Nokia),

3081 Leddie Stenvie (ST-Ericsson), Neil Trevett (Nvidia), Per Wennersten (Eri csson),

3082 Per-Erik Brodin (Ericsson), Shiki Okasaka (Google), Tom Olson (ARM), Zhe ngrong Yao (Ericsson),

3083 and the members of the Khronos WebGL Working Group.

3084 </p>

3085

3086 </body>

3087 </html>

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