third_party/webgl/doc/spec/WebGL-spec-13288.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/

Patch Set: Created 8 years, 10 months ago

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

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

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-<head>

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

- <title>WebGL Specification</title>

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

-</head>

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

-

- <div class=head>

- <p>

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

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

- </a>

- </p>

- </div>

- <div class=head>

- <p>

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

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

- </a>

- </p>

- </div>

-

- <h1>WebGL 1.0 Specification</h1>

- <h2 class="no-toc">23 December 2010 (r13288)</h2>

- <dl>

- <dt>This version:

- <dd>

- <a href="https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/WebGL-spec.html">

- https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/WebGL-spec.html

- </a>

- <br>

- <a href="https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/webgl.idl">

- <b>WebIDL:</b> https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/webgl.idl

- </a>

- </dd>

- <dt>Latest version:

- <dd>

- <a href="https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/WebGL-spec.html">

- https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/WebGL-spec.html

- </a>

- <br>

- <a href="https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/webgl.idl">

- <b>WebIDL:</b> https://cvs.khronos.org/svn/repos/registry/trunk/public/webgl/doc/spec/webgl.idl

- </a>

- </dd>

- <dt>Previous version:

- <dd>

- none

- </dd>

- <dt>Editor:

- <dd>

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

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

- </dd>

- </dl>

- <hr />

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

- <p>

- This specification describes an additional rendering context and support

- objects for the

- <a

- href="http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html"

- title="HTML 5 Canvas Element">

- HTML 5 <span class="prop-name">canvas</span> element.

- </a>

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

- </p>

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

-

- <p>

- Discussion and questions about this specification are

- welcome on the (<a

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

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

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

- </p>

-

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

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

- <h2>Introduction</h2>

- <div class="note">

- <p>

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

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

- rendering functionality, but in a HTML context. WebGL is

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

- The HTML Canvas provides a destination for programmatic

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

- using different rendering APIs. The only such interface

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

- rendering context, CanvasRenderingContext2D. This document

- describes another such interface, WebGLRenderingContext, which

- presents the WebGL API.

- </p>

- <p>

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

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

- chooses the approach of providing flexible primitives that can

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

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

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

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

- straightforward for developers familiar with modern desktop

- OpenGL or OpenGL ES 2.0 development to transition to WebGL

- development.

- </p>

- <p>

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

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

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

- they may contain errors. In cases where a man page

- contradicts the spec, the spec is the final authority.

- </p>

- <p>

- The remaining sections of this document are intended to be read in conjunction

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

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

- Unless otherwise specified, the behaviour of each method is defined by the

- OpenGL ES 2.0 specification. This specification may diverge from OpenGL ES 2.0

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

- OpenGL ES 2.0 leaves implementation-defined. These differences are summarized in the

- <a href="#webgl_gl_differences">Differences Between WebGL and OpenGL ES 2.0</a> section.

- </p>

- </div>

-

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

- <p>

- Before using the WebGL API, the author must obtain a WebGLRenderingContext object

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

- OpenGL state and render to the drawing buffer, which must also be created at the time of

- context creation. The author may supply configuration options for this drawing buffer, otherwise

- default values shall be used as specified elsewhere in this document. This drawing buffer

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

- but only if the drawing buffer has been modified since the last compositing operation.

- </p>

-

- <h3>The <span class=prop-name>‘<code class=property>canvas</code>’</span> Element</h3>

- <p>

- A WebGLRenderingContext object shall be created by calling the <code>getContext()</code>

- method of a given HTMLCanvasElement object with the exact string

- ‘<code class=property>webgl</code>’. This string is case sensitive. When called

- for the first time, a WebGLRenderingContext object is created and returned. Also at this

- time a drawing buffer shall be created. Subsequent calls to <code>getContext()</code> with

- the same string shall return the same object. If <code>getContext()</code> is subsequently

- called with any other string, the WebGLRenderingContext shall be detached from its Canvas

- object (the <code>canvas</code> attribute will be null). API calls may still be made on the

- WebGLRenderingContext object and readPixels() may be used to obtain the contents of the

- drawing buffer, but the contents shall no longer be shown on the page.

- </p>

- <p>

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

- parameter shall be a WebGLContextAttributes object containing configuration parameters to be

- used in creating the drawing buffer.

- See <a href="#WEBGLCONTEXTATTRIBUTES">WebGLContextAttributes</a> for more details.

- </p>

- <p>

- The passed attributes are requests, not requirements. The WebGL implementation does not

- guarantee that they will be obeyed, but should make a best effort to honor them.

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

- shall not cause a failure to create a WebGLRenderingContext. The attributes actually used to

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

- WebGLRenderingContext.

- </p>

- <p>

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

- string, the passed WebGLContextAttributes object, if any, shall be ignored.

- <p>

- </p>

-

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

- <p>

- The drawing buffer into which the API calls are rendered shall be defined upon creation of

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

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

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

- and <code>height</code> attributes of the HTMLCanvasElement. The table below also shows

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

- changed.

- </p>

- <table class="foo">

- <tr><th>Buffer</th><th>Clear value</th><th>Minimum size</th><th>Defined By default?</th></tr>

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

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

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

- </table>

- <br>

- <p>

- If the requested width or height cannot be satisfied, either when the drawing buffer is first

- created or when the <code>width</code> and <code>height</code> attributes of the

- <code>HTMLCanvasElement</code> are changed, a drawing buffer with smaller dimensions shall

- be created. The dimensions actually used are implementation dependent and there is no

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

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

- <code>drawingBufferHeight</code> attributes.

- </p>

- <p>

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

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

- to define whether the color buffer will include an alpha channel. If defined, the

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

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

- <code>getContext</code>. No facility is provided to change the attributes of the drawing

- buffer after its creation.

- </p>

- <p>

- WebGL presents its drawing buffer to the HTML page compositor immediately before a compositing

- operation, but only if the drawing buffer has been modified since the last compositing operation.

- Before the drawing buffer is presented for compositing the implementation shall ensure that all

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

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

- above.

- </p>

- <p>

- This default behavior can be changed by setting the <code>preserveDrawingBuffer</code>

- attribute of the <a href="#WEBGLCONTEXTATTRIBUTES">WebGLContextAttributes</a> object to

- true, the contents of the drawing buffer can be preserved until the author either clears

- or overwrites them. If this flag is false attempting to perform operations using this

- context as a source image after the rendering function has returned can lead to undefined

- behavior. This includes <code>readPixels</code> or <code>toDataURL</code> calls, or using

- this context as the source image of another context's <code>texImage2D</code> or

- <code>drawImage</code> call.

- </p>

- <div class="note">

- <p>

- While it is sometimes desirable to preserve the drawing buffer, it can cause significant

- performance loss on some platforms. Whenever possible this flag should remain false

- and other techniques used. Techniques like synchronous drawing buffer access (e.g.,

- calling <code>readPixels</code> or <code>toDataURL</code> in the same function that

- renders to the drawing buffer) can be used to get the contents of the drawing buffer.

- If the author needs to render to the same drawing buffer over a series of calls, a

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

- </p>

- <p>

- One way for an implementation to guarantee buffers do not contain information from another

- process is to clear the buffer to the default values specified in the OpenGL ES 2.0

- specification <a href="#refsGLES20">[GLES20]</a>.

- </p>

- </div>

-

- <h3>The WebGL Viewport</h3>

- <p>

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

- rendering results in the drawing buffer. Upon creation of the WebGL context, the viewport is

- initialized to a rectangle with origin at (0, 0) and width and height equal to (canvas.width,

- canvas.height).

- </p>

- <p>

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

- resizing of the canvas element.

- </p>

- <div class="example">

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

- handle the case where the canvas is resized. The following ECMAScript example illustrates how

- a WebGL program might resize the canvas programmatically.

- <pre>

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

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

-canvas.width = newWidth;

-canvas.height = newHeight;

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

- </pre>

- </div>

- <p>

- <em>Rationale</em>: automatically setting the viewport will interfere with applications that set

- it manually. Applications are expected to use <code>onresize</code> handlers to respond to

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

- </p>

-

- <h3><a name="PREMULTIPLIED_ALPHA">Premultiplied Alpha, Canvas APIs and texImage2D</a></h3>

- <p>

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

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

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

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

- </p>

- <p>

- The HTML Canvas APIs <code>toDataURL</code> and <code>drawImage</code> must respect

- the <code>premultipliedAlpha</code> context creation parameter. When <code>toDataURL</code>

- is called against a Canvas into which WebGL content is being rendered, then if the requested

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

- the <code>premultipliedAlpha</code> parameter set to true, then the pixel values must be

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

- this operation is lossy.

- </p>

- <p>

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

- of <code>CanvasRenderingContext2D</code> may or may not need to modify the the rendered

- WebGL content during the drawing operation, depending on the premultiplication needs of the

- <code>CanvasRenderingContext2D</code> implementation.

- </p>

- <p>

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

- the setting of the <code>premultipliedAlpha</code> context creation parameter of the passed

- canvas and the <code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code> pixel store parameter of the

- destination WebGL context, the pixel data may need to be changed to or from premultiplied

- form.

- </p>

-

- <h2>WebGL Resources</h2>

- <p>

- OpenGL manages several types of resources as part of its state. These are identified

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

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

- from the WebGLObject interface. Currently supported resources are:

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

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

- WebGLObject subclass for each type. Data from the underlying graphics library are

- stored in these objects and are fully managed by them. The resources represented

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

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

- valid reference to it OR as long as it is bound by the underlying graphics library.

- When none of these conditions exist the user agent can, at any point, delete the object

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

- when the underlying resource is released then the delete call can be made explicitly.

- </p>

-

- <h2>Security</h2>

- <p>

- </p>

-

- <h3>Resource Restrictions</h3>

- <p>

- WebGL resources such as textures and vertex buffer objects (VBOs) must always

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

- data values. Creating a resource without initial values is commonly used to

- reserve space for a texture or VBO, which is then modified using <code>texSubImage</code> or

- <code>bufferSubData</code> calls. If initial data is not provided to these calls, the WebGL

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

- the default 1.0 clear depth. For example, this may require creating a temporary buffer of 0

- values the size of a requested VBO, so that it can be initialized correctly. All other

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

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

- </p>

- <p>

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

- <code>drawElements</code> or <code>drawArrays</code>, the WebGL implementation must ensure

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

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

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

- </p>

-

- <h3>Origin Restrictions</h3>

- <p>

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

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

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

- if any of the following actions occur:

- </p>

- <ul>

- <li>The <code>texImage2D</code> method is called with an <code>HTMLImageElement</code> or

- <code>HTMLVideoElement</code> whose origin is not the same as that of the Document

- object that owns the canvas element.

- <li>The <code>texImage2D</code> method is called with an <code>HTMLCanvasElement</code>

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

- </ul>

- <p>

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

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

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

- </p>

-

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

- <p>

- A WebGL implementation must only accept shaders which conform to The OpenGL ES Shading

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

- the minimum functionality mandated in Sections 4 and 5 of Appendix A. In particular, a shader

- referencing state variables or functions that are available in other versions of GLSL (such

- as that found in versions of OpenGL for the desktop), must not be allowed to load.

- </p>

- <p>

- In addition to the reserved identifiers in the aforementioned specification, identifiers

- starting with "webgl_" and "_webgl_" are reserved for use by WebGL. A shader which declares

- a function, variable, structure name, or structure field starting with these prefixes must

- not be allowed to load.

- </p>

-

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

- <div class="note">

- <p>

- It is possible to create, either intentionally or unintentionally, combinations of shaders and

- geometry that take an undesirably long time to render. This issue is analogous to that of

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

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

- </p>

- <p>

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

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

- are insufficient to prevent long rendering times, and such limits would prevent shader authors

- from implementing common algorithms.

- </p>

- <p>

- User agents should implement safeguards to prevent excessively long rendering times and

- associated loss of interactivity. Suggested safeguards include:

- </p>

- <ul>

- <li> Splitting up draw calls with large numbers of elements into smaller draw calls.

- <li> Timing individual draw calls and forbidding further rendering from a page if a certain

- timeout is exceeded.

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

- system level to limit the duration of draw calls.

- <li> Separating the graphics rendering of the user agent into a distinct operating system

- process which can be terminated and restarted without losing application state.

- </ul>

- <p>

- The supporting infrastructure at the OS and graphics API layer is expected to improve over time,

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

- </p>

- </div>

-

- <h2>DOM Interfaces</h2>

- <p>

- This section describes the interfaces and functionality added to the

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

- </p>

-

- <h3>Types</h3>

- <p>

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

- </p>

- <pre class="idl">

-typedef events::Event Event;

-typedef html::HTMLCanvasElement HTMLCanvasElement;

-typedef html::HTMLImageElement HTMLImageElement;

-typedef html::HTMLVideoElement HTMLVideoElement;

-typedef html::ImageData ImageData;

-typedef unsigned long GLenum;

-typedef boolean GLboolean;

-typedef unsigned long GLbitfield;

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

-typedef short GLshort;

-typedef long GLint;

-typedef long GLsizei;

-typedef long GLsizeiptr;

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

-typedef unsigned short GLushort;

-typedef unsigned long GLuint;

-typedef float GLfloat;

-typedef float GLclampf;

-</pre>

-

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

- <p>

- The <code>WebGLContextAttributes</code> interface contains drawing surface attributes and is

- passed as the second parameter to <code>getContext</code>. A native object may be supplied

- as this parameter; the specified attributes will be queried from this object.

- </p>

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

- attribute boolean alpha;

- attribute boolean depth;

- attribute boolean stencil;

- attribute boolean antialias;

- attribute boolean premultipliedAlpha;

- attribute boolean preserveDrawingBuffer;

-};</pre>

- <h4>Context creation parameters</h4>

- <p>

- The following list describes each attribute in the WebGLContextAttributes object and its

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

- second parameter is passed to <code>getContext</code>, or if a native object is passed which

- has no attribute of the given name.

- </p>

- <dl>

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

- <dd>

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

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

- compositing with the page. If the value is false, no alpha buffer is available.

- </dd>

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

- <dd>

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

- buffer of at least 16 bits. If the value is false, no depth buffer is

- available.

- </dd>

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

- <dd>

- <em>Default: false</em>. If the value is true, the drawing buffer has a stencil

- buffer of at least 8 bits. If the value is false, no stencil buffer is

- available.

- </dd>

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

- <dd>

- <em>Default: true</em>. If the value is true and the implementation supports

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

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

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

- </dd>

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

- <dd>

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

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

- page compositor will assume that colors in the drawing buffer are not

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

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

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

- </dd>

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

- <dd>

- <em>Default: false</em>. If false, once the drawing buffer is presented

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

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

- All elements of the drawing buffer (color, depth and stencil) are cleared.

- If the value is true the buffers will not be cleared and will preserve

- their values until cleared or overwritten by the author.

- <blockquote>

- <em>

- On some hardware setting the <code>preserveDrawingBuffer</code> flag

- to true can have significant performance implications.

- </em>

- </blockquote>

- </dd>

- </dl>

- <div class="example">

- Here is an ECMAScript example which passes a WebGLContextAttributes argument

- to <code>getContext</code>. It assumes the presence of a canvas element named "canvas1" on the

- page.

- <pre>

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

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

- { antialias: false,

- stencil: true });

- </pre>

- </div>

-

- <h3>WebGLObject</h3>

- <p>

- The <code>WebGLObject</code> interface is the parent interface for all GL objects.

- </p>

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

-};</pre>

-

- <h3>WebGLBuffer</h3>

- <p>

- The <code>WebGLBuffer</code> interface represents an OpenGL Buffer Object. The

- underlying object is created as if by calling glGenBuffers

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenBuffers.xml">man page</a>)</span>

- , bound as if by calling glBindBuffer

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindBuffer.xml">man page</a>)</span>

- and destroyed as if by calling glDeleteBuffers

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteBuffers.xml">man page</a>)</span>

- .

- </p>

- <pre class="idl">interface <dfn id="WebGLBuffer">WebGLBuffer</dfn> : WebGLObject {

-};</pre>

-

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

- <p>

- The <code>WebGLFramebuffer</code> interface represents an OpenGL Framebuffer Object. The

- underlying object is created as if by calling glGenFramebuffers

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenFramebuffers.xml">man page</a>)</span>

- , bound as if by calling glBindFramebuffer

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindFramebuffer.xml">man page</a>)</span>

- and destroyed as if by calling glDeleteFramebuffers

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteFramebuffers.xml">man page</a>)</span>

- .

- </p>

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

-};</pre>

-

- <h3>WebGLProgram</h3>

- <p>

- The <code>WebGLProgram</code> interface represents an OpenGL Program Object. The

- underlying object is created as if by calling glCreateProgram

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCreateProgram.xml">man page</a>)</span>

- , used as if by calling glUseProgram

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUseProgram.xml">man page</a>)</span>

- and destroyed as if by calling glDeleteProgram

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteProgram.xml">man page</a>)</span>

- .

- </p>

- <pre class="idl">interface <dfn id="WebGLProgram">WebGLProgram</dfn> : WebGLObject {

-};</pre>

-

- <h3>WebGLRenderbuffer</h3>

- <p>

- The <code>WebGLRenderbuffer</code> interface represents an OpenGL Renderbuffer Object. The

- underlying object is created as if by calling glGenRenderbuffers

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenRenderbuffers.xml">man page</a>)</span>

- , bound as if by calling glBindRenderbuffer

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindRenderbuffer.xml">man page</a>)</span>

- and destroyed as if by calling glDeleteRenderbuffers

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteRenderbuffers.xml">man page</a>)</span>

- .

- </p>

- <pre class="idl">interface <dfn id="WebGLRenderbuffer">WebGLRenderbuffer</dfn> : WebGLObject {

-};</pre>

-

- <h3>WebGLShader</h3>

- <p>

- The <code>WebGLShader</code> interface represents an OpenGL Shader Object. The

- underlying object is created as if by calling glCreateShader

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCreateShader.xml">man page</a>)</span>

- , attached to a Program as if by calling glAttachShader

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glAttachShader.xml">man page</a>)</span>

- and destroyed as if by calling glDeleteShader

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteShader.xml">man page</a>)</span>

- .

- </p>

- <pre class="idl">interface <dfn id="WebGLShader">WebGLShader</dfn> : WebGLObject {

-};</pre>

-

- <h3>WebGLTexture</h3>

- <p>

- The <code>WebGLTexture</code> interface represents an OpenGL Texture Object. The

- underlying object is created as if by calling glGenTextures

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.13, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenTextures.xml">man page</a>)</span>

- , bound as if by calling glBindTexture

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.13, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindTexture.xml">man page</a>)</span>

- and destroyed as if by calling glDeleteTextures

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.13, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteTextures.xml">man page</a>)</span>

- .

- </p>

- <pre class="idl">interface <dfn id="WebGLTexture">WebGLTexture</dfn> : WebGLObject {

-};</pre>

-

- <h3>WebGLUniformLocation</h3>

- <p>

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

- in a shader program.

- </p>

- <pre class="idl">interface <dfn id="WebGLUniformLocation">WebGLUniformLocation</dfn> {

-};</pre>

-

- <h3>WebGLActiveInfo</h3>

- <p>

- The <code>WebGLActiveInfo</code> interface represents the information returned

- from the getActiveAttrib and getActiveUniform calls.

- </p>

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

- readonly attribute GLint size;

- readonly attribute GLenum type;

- readonly attribute DOMString name;

-};</pre>

- <h4>Attributes</h4>

- <p>

- The following attributes are available:

- </p>

- <dl class="methods">

- <dt>

- <code class=attribute-name>

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

- size

- </a>

- </code>

- of type <code>GLint</code>

- <dd>

- The size of the requested variable.

- <dt>

- <code class=attribute-name>

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

- type

- </a>

- </code>

- of type <code>GLenum</code>

- <dd>

- The data type of the requested variable.

- <dt>

- <code class=attribute-name>

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

- name

- </a>

- </code>

- of type <code>DOMString</code>

- <dd>

- The name of the requested variable.

- </dl>

-

- <h3><a name="ARRAYBUFFER">ArrayBuffer</a> and <a name="TYPEDARRAY">Typed Arrays</a></h3>

- <p>

- Vertex, index, texture, and other data is transferred to the WebGL implementation using

- the <a href="TypedArray-spec.html#ARRAYBUFFER">ArrayBuffer</a>

- and <a href="TypedArray-spec.html#TYPEDARRAYS">views</a> defined in

- the <a href="TypedArray-spec.html">Typed Array</a>

- specification <a href="#refsTYPEDARRAYS">[TYPEDARRAYS]</a>. All of the typed array views

- except <tt>Float64Array</tt> may be used in conjunction with WebGL; OpenGL ES 2.0, and

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

- </p>

- <p>

- Typed Arrays support the creation of interleaved, heterogeneous vertex data; uploading of

- distinct blocks of data into a large vertex buffer object; and most other use cases required

- by OpenGL programs.

- </p>

- <div class="example">

- Here is an ECMAScript example showing access to the same ArrayBuffer using different types of

- typed arrays. In this case the buffer contains a floating point vertex position (x, y, z)

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

- <pre>

-var numVertices = 100; // for example

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

-var vertexSize = 3 * Float32Array.BYTES_PER_ELEMENT +

- 4 * Uint8Array.BYTES_PER_ELEMENT;

-var vertexSizeInFloats = vertexSize / Float32Array.BYTES_PER_ELEMENT;

-// Allocate the buffer

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

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

-var positionArray = new Float32Array(buf);

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

-var colorArray = new Uint8Array(buf);

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

-var positionIdx = 0;

-var colorIdx = 3 * Float32Array.BYTES_PER_ELEMENT;

-// Initialize the buffer

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

- positionArray[positionIdx] = ...;

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

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

- colorArray[colorIdx] = ...;

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

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

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

- positionIdx += vertexSizeInFloats;

- colorIdx += vertexSize;

- </pre>

- </div>

-

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

- <p>

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

- OpenGL ES 2.0 style rendering into the canvas element.

- </p>

- <pre class="idl">interface <dfn id="WebGLRenderingContext">WebGLRenderingContext</dfn> {

- /* ClearBufferMask */

- const GLenum DEPTH_BUFFER_BIT = 0x00000100;

- const GLenum STENCIL_BUFFER_BIT = 0x00000400;

- const GLenum COLOR_BUFFER_BIT = 0x00004000;

- /* BeginMode */

- const GLenum POINTS = 0x0000;

- const GLenum LINES = 0x0001;

- const GLenum LINE_LOOP = 0x0002;

- const GLenum LINE_STRIP = 0x0003;

- const GLenum TRIANGLES = 0x0004;

- const GLenum TRIANGLE_STRIP = 0x0005;

- const GLenum TRIANGLE_FAN = 0x0006;

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

- /* NEVER */

- /* LESS */

- /* EQUAL */

- /* LEQUAL */

- /* GREATER */

- /* NOTEQUAL */

- /* GEQUAL */

- /* ALWAYS */

- /* BlendingFactorDest */

- const GLenum ZERO = 0;

- const GLenum ONE = 1;

- const GLenum SRC_COLOR = 0x0300;

- const GLenum ONE_MINUS_SRC_COLOR = 0x0301;

- const GLenum SRC_ALPHA = 0x0302;

- const GLenum ONE_MINUS_SRC_ALPHA = 0x0303;

- const GLenum DST_ALPHA = 0x0304;

- const GLenum ONE_MINUS_DST_ALPHA = 0x0305;

- /* BlendingFactorSrc */

- /* ZERO */

- /* ONE */

- const GLenum DST_COLOR = 0x0306;

- const GLenum ONE_MINUS_DST_COLOR = 0x0307;

- const GLenum SRC_ALPHA_SATURATE = 0x0308;

- /* SRC_ALPHA */

- /* ONE_MINUS_SRC_ALPHA */

- /* DST_ALPHA */

- /* ONE_MINUS_DST_ALPHA */

- /* BlendEquationSeparate */

- const GLenum FUNC_ADD = 0x8006;

- const GLenum BLEND_EQUATION = 0x8009;

- const GLenum BLEND_EQUATION_RGB = 0x8009; /* same as BLEND_EQUATION */

- const GLenum BLEND_EQUATION_ALPHA = 0x883D;

- /* BlendSubtract */

- const GLenum FUNC_SUBTRACT = 0x800A;

- const GLenum FUNC_REVERSE_SUBTRACT = 0x800B;

- /* Separate Blend Functions */

- const GLenum BLEND_DST_RGB = 0x80C8;

- const GLenum BLEND_SRC_RGB = 0x80C9;

- const GLenum BLEND_DST_ALPHA = 0x80CA;

- const GLenum BLEND_SRC_ALPHA = 0x80CB;

- const GLenum CONSTANT_COLOR = 0x8001;

- const GLenum ONE_MINUS_CONSTANT_COLOR = 0x8002;

- const GLenum CONSTANT_ALPHA = 0x8003;

- const GLenum ONE_MINUS_CONSTANT_ALPHA = 0x8004;

- const GLenum BLEND_COLOR = 0x8005;

- /* Buffer Objects */

- const GLenum ARRAY_BUFFER = 0x8892;

- const GLenum ELEMENT_ARRAY_BUFFER = 0x8893;

- const GLenum ARRAY_BUFFER_BINDING = 0x8894;

- const GLenum ELEMENT_ARRAY_BUFFER_BINDING = 0x8895;

- const GLenum STREAM_DRAW = 0x88E0;

- const GLenum STATIC_DRAW = 0x88E4;

- const GLenum DYNAMIC_DRAW = 0x88E8;

- const GLenum BUFFER_SIZE = 0x8764;

- const GLenum BUFFER_USAGE = 0x8765;

- const GLenum CURRENT_VERTEX_ATTRIB = 0x8626;

- /* CullFaceMode */

- const GLenum FRONT = 0x0404;

- const GLenum BACK = 0x0405;

- const GLenum FRONT_AND_BACK = 0x0408;

- /* DepthFunction */

- /* NEVER */

- /* LESS */

- /* EQUAL */

- /* LEQUAL */

- /* GREATER */

- /* NOTEQUAL */

- /* GEQUAL */

- /* ALWAYS */

- /* EnableCap */

- /* TEXTURE_2D */

- const GLenum CULL_FACE = 0x0B44;

- const GLenum BLEND = 0x0BE2;

- const GLenum DITHER = 0x0BD0;

- const GLenum STENCIL_TEST = 0x0B90;

- const GLenum DEPTH_TEST = 0x0B71;

- const GLenum SCISSOR_TEST = 0x0C11;

- const GLenum POLYGON_OFFSET_FILL = 0x8037;

- const GLenum SAMPLE_ALPHA_TO_COVERAGE = 0x809E;

- const GLenum SAMPLE_COVERAGE = 0x80A0;

- /* ErrorCode */

- const GLenum NO_ERROR = 0;

- const GLenum INVALID_ENUM = 0x0500;

- const GLenum INVALID_VALUE = 0x0501;

- const GLenum INVALID_OPERATION = 0x0502;

- const GLenum OUT_OF_MEMORY = 0x0505;

- /* FrontFaceDirection */

- const GLenum CW = 0x0900;

- const GLenum CCW = 0x0901;

- /* GetPName */

- const GLenum LINE_WIDTH = 0x0B21;

- const GLenum ALIASED_POINT_SIZE_RANGE = 0x846D;

- const GLenum ALIASED_LINE_WIDTH_RANGE = 0x846E;

- const GLenum CULL_FACE_MODE = 0x0B45;

- const GLenum FRONT_FACE = 0x0B46;

- const GLenum DEPTH_RANGE = 0x0B70;

- const GLenum DEPTH_WRITEMASK = 0x0B72;

- const GLenum DEPTH_CLEAR_VALUE = 0x0B73;

- const GLenum DEPTH_FUNC = 0x0B74;

- const GLenum STENCIL_CLEAR_VALUE = 0x0B91;

- const GLenum STENCIL_FUNC = 0x0B92;

- const GLenum STENCIL_FAIL = 0x0B94;

- const GLenum STENCIL_PASS_DEPTH_FAIL = 0x0B95;

- const GLenum STENCIL_PASS_DEPTH_PASS = 0x0B96;

- const GLenum STENCIL_REF = 0x0B97;

- const GLenum STENCIL_VALUE_MASK = 0x0B93;

- const GLenum STENCIL_WRITEMASK = 0x0B98;

- const GLenum STENCIL_BACK_FUNC = 0x8800;

- const GLenum STENCIL_BACK_FAIL = 0x8801;

- const GLenum STENCIL_BACK_PASS_DEPTH_FAIL = 0x8802;

- const GLenum STENCIL_BACK_PASS_DEPTH_PASS = 0x8803;

- const GLenum STENCIL_BACK_REF = 0x8CA3;

- const GLenum STENCIL_BACK_VALUE_MASK = 0x8CA4;

- const GLenum STENCIL_BACK_WRITEMASK = 0x8CA5;

- const GLenum VIEWPORT = 0x0BA2;

- const GLenum SCISSOR_BOX = 0x0C10;

- /* SCISSOR_TEST */

- const GLenum COLOR_CLEAR_VALUE = 0x0C22;

- const GLenum COLOR_WRITEMASK = 0x0C23;

- const GLenum UNPACK_ALIGNMENT = 0x0CF5;

- const GLenum PACK_ALIGNMENT = 0x0D05;

- const GLenum MAX_TEXTURE_SIZE = 0x0D33;

- const GLenum MAX_VIEWPORT_DIMS = 0x0D3A;

- const GLenum SUBPIXEL_BITS = 0x0D50;

- const GLenum RED_BITS = 0x0D52;

- const GLenum GREEN_BITS = 0x0D53;

- const GLenum BLUE_BITS = 0x0D54;

- const GLenum ALPHA_BITS = 0x0D55;

- const GLenum DEPTH_BITS = 0x0D56;

- const GLenum STENCIL_BITS = 0x0D57;

- const GLenum POLYGON_OFFSET_UNITS = 0x2A00;

- /* POLYGON_OFFSET_FILL */

- const GLenum POLYGON_OFFSET_FACTOR = 0x8038;

- const GLenum TEXTURE_BINDING_2D = 0x8069;

- const GLenum SAMPLE_BUFFERS = 0x80A8;

- const GLenum SAMPLES = 0x80A9;

- const GLenum SAMPLE_COVERAGE_VALUE = 0x80AA;

- const GLenum SAMPLE_COVERAGE_INVERT = 0x80AB;

- /* GetTextureParameter */

- /* TEXTURE_MAG_FILTER */

- /* TEXTURE_MIN_FILTER */

- /* TEXTURE_WRAP_S */

- /* TEXTURE_WRAP_T */

- const GLenum NUM_COMPRESSED_TEXTURE_FORMATS = 0x86A2;

- const GLenum COMPRESSED_TEXTURE_FORMATS = 0x86A3;

- /* HintMode */

- const GLenum DONT_CARE = 0x1100;

- const GLenum FASTEST = 0x1101;

- const GLenum NICEST = 0x1102;

- /* HintTarget */

- const GLenum GENERATE_MIPMAP_HINT = 0x8192;

- /* DataType */

- const GLenum BYTE = 0x1400;

- const GLenum UNSIGNED_BYTE = 0x1401;

- const GLenum SHORT = 0x1402;

- const GLenum UNSIGNED_SHORT = 0x1403;

- const GLenum INT = 0x1404;

- const GLenum UNSIGNED_INT = 0x1405;

- const GLenum FLOAT = 0x1406;

- /* PixelFormat */

- const GLenum DEPTH_COMPONENT = 0x1902;

- const GLenum ALPHA = 0x1906;

- const GLenum RGB = 0x1907;

- const GLenum RGBA = 0x1908;

- const GLenum LUMINANCE = 0x1909;

- const GLenum LUMINANCE_ALPHA = 0x190A;

- /* PixelType */

- /* UNSIGNED_BYTE */

- const GLenum UNSIGNED_SHORT_4_4_4_4 = 0x8033;

- const GLenum UNSIGNED_SHORT_5_5_5_1 = 0x8034;

- const GLenum UNSIGNED_SHORT_5_6_5 = 0x8363;

- /* Shaders */

- const GLenum FRAGMENT_SHADER = 0x8B30;

- const GLenum VERTEX_SHADER = 0x8B31;

- const GLenum MAX_VERTEX_ATTRIBS = 0x8869;

- const GLenum MAX_VERTEX_UNIFORM_VECTORS = 0x8DFB;

- const GLenum MAX_VARYING_VECTORS = 0x8DFC;

- const GLenum MAX_COMBINED_TEXTURE_IMAGE_UNITS = 0x8B4D;

- const GLenum MAX_VERTEX_TEXTURE_IMAGE_UNITS = 0x8B4C;

- const GLenum MAX_TEXTURE_IMAGE_UNITS = 0x8872;

- const GLenum MAX_FRAGMENT_UNIFORM_VECTORS = 0x8DFD;

- const GLenum SHADER_TYPE = 0x8B4F;

- const GLenum DELETE_STATUS = 0x8B80;

- const GLenum LINK_STATUS = 0x8B82;

- const GLenum VALIDATE_STATUS = 0x8B83;

- const GLenum ATTACHED_SHADERS = 0x8B85;

- const GLenum ACTIVE_UNIFORMS = 0x8B86;

- const GLenum ACTIVE_UNIFORM_MAX_LENGTH = 0x8B87;

- const GLenum ACTIVE_ATTRIBUTES = 0x8B89;

- const GLenum ACTIVE_ATTRIBUTE_MAX_LENGTH = 0x8B8A;

- const GLenum SHADING_LANGUAGE_VERSION = 0x8B8C;

- const GLenum CURRENT_PROGRAM = 0x8B8D;

- /* StencilFunction */

- const GLenum NEVER = 0x0200;

- const GLenum LESS = 0x0201;

- const GLenum EQUAL = 0x0202;

- const GLenum LEQUAL = 0x0203;

- const GLenum GREATER = 0x0204;

- const GLenum NOTEQUAL = 0x0205;

- const GLenum GEQUAL = 0x0206;

- const GLenum ALWAYS = 0x0207;

- /* StencilOp */

- /* ZERO */

- const GLenum KEEP = 0x1E00;

- const GLenum REPLACE = 0x1E01;

- const GLenum INCR = 0x1E02;

- const GLenum DECR = 0x1E03;

- const GLenum INVERT = 0x150A;

- const GLenum INCR_WRAP = 0x8507;

- const GLenum DECR_WRAP = 0x8508;

- /* StringName */

- const GLenum VENDOR = 0x1F00;

- const GLenum RENDERER = 0x1F01;

- const GLenum VERSION = 0x1F02;

- /* TextureMagFilter */

- const GLenum NEAREST = 0x2600;

- const GLenum LINEAR = 0x2601;

- /* TextureMinFilter */

- /* NEAREST */

- /* LINEAR */

- const GLenum NEAREST_MIPMAP_NEAREST = 0x2700;

- const GLenum LINEAR_MIPMAP_NEAREST = 0x2701;

- const GLenum NEAREST_MIPMAP_LINEAR = 0x2702;

- const GLenum LINEAR_MIPMAP_LINEAR = 0x2703;

- /* TextureParameterName */

- const GLenum TEXTURE_MAG_FILTER = 0x2800;

- const GLenum TEXTURE_MIN_FILTER = 0x2801;

- const GLenum TEXTURE_WRAP_S = 0x2802;

- const GLenum TEXTURE_WRAP_T = 0x2803;

- /* TextureTarget */

- const GLenum TEXTURE_2D = 0x0DE1;

- const GLenum TEXTURE = 0x1702;

- const GLenum TEXTURE_CUBE_MAP = 0x8513;

- const GLenum TEXTURE_BINDING_CUBE_MAP = 0x8514;

- const GLenum TEXTURE_CUBE_MAP_POSITIVE_X = 0x8515;

- const GLenum TEXTURE_CUBE_MAP_NEGATIVE_X = 0x8516;

- const GLenum TEXTURE_CUBE_MAP_POSITIVE_Y = 0x8517;

- const GLenum TEXTURE_CUBE_MAP_NEGATIVE_Y = 0x8518;

- const GLenum TEXTURE_CUBE_MAP_POSITIVE_Z = 0x8519;

- const GLenum TEXTURE_CUBE_MAP_NEGATIVE_Z = 0x851A;

- const GLenum MAX_CUBE_MAP_TEXTURE_SIZE = 0x851C;

- /* TextureUnit */

- const GLenum TEXTURE0 = 0x84C0;

- const GLenum TEXTURE1 = 0x84C1;

- const GLenum TEXTURE2 = 0x84C2;

- const GLenum TEXTURE3 = 0x84C3;

- const GLenum TEXTURE4 = 0x84C4;

- const GLenum TEXTURE5 = 0x84C5;

- const GLenum TEXTURE6 = 0x84C6;

- const GLenum TEXTURE7 = 0x84C7;

- const GLenum TEXTURE8 = 0x84C8;

- const GLenum TEXTURE9 = 0x84C9;

- const GLenum TEXTURE10 = 0x84CA;

- const GLenum TEXTURE11 = 0x84CB;

- const GLenum TEXTURE12 = 0x84CC;

- const GLenum TEXTURE13 = 0x84CD;

- const GLenum TEXTURE14 = 0x84CE;

- const GLenum TEXTURE15 = 0x84CF;

- const GLenum TEXTURE16 = 0x84D0;

- const GLenum TEXTURE17 = 0x84D1;

- const GLenum TEXTURE18 = 0x84D2;

- const GLenum TEXTURE19 = 0x84D3;

- const GLenum TEXTURE20 = 0x84D4;

- const GLenum TEXTURE21 = 0x84D5;

- const GLenum TEXTURE22 = 0x84D6;

- const GLenum TEXTURE23 = 0x84D7;

- const GLenum TEXTURE24 = 0x84D8;

- const GLenum TEXTURE25 = 0x84D9;

- const GLenum TEXTURE26 = 0x84DA;

- const GLenum TEXTURE27 = 0x84DB;

- const GLenum TEXTURE28 = 0x84DC;

- const GLenum TEXTURE29 = 0x84DD;

- const GLenum TEXTURE30 = 0x84DE;

- const GLenum TEXTURE31 = 0x84DF;

- const GLenum ACTIVE_TEXTURE = 0x84E0;

- /* TextureWrapMode */

- const GLenum REPEAT = 0x2901;

- const GLenum CLAMP_TO_EDGE = 0x812F;

- const GLenum MIRRORED_REPEAT = 0x8370;

- /* Uniform Types */

- const GLenum FLOAT_VEC2 = 0x8B50;

- const GLenum FLOAT_VEC3 = 0x8B51;

- const GLenum FLOAT_VEC4 = 0x8B52;

- const GLenum INT_VEC2 = 0x8B53;

- const GLenum INT_VEC3 = 0x8B54;

- const GLenum INT_VEC4 = 0x8B55;

- const GLenum BOOL = 0x8B56;

- const GLenum BOOL_VEC2 = 0x8B57;

- const GLenum BOOL_VEC3 = 0x8B58;

- const GLenum BOOL_VEC4 = 0x8B59;

- const GLenum FLOAT_MAT2 = 0x8B5A;

- const GLenum FLOAT_MAT3 = 0x8B5B;

- const GLenum FLOAT_MAT4 = 0x8B5C;

- const GLenum SAMPLER_2D = 0x8B5E;

- const GLenum SAMPLER_CUBE = 0x8B60;

- /* Vertex Arrays */

- const GLenum VERTEX_ATTRIB_ARRAY_ENABLED = 0x8622;

- const GLenum VERTEX_ATTRIB_ARRAY_SIZE = 0x8623;

- const GLenum VERTEX_ATTRIB_ARRAY_STRIDE = 0x8624;

- const GLenum VERTEX_ATTRIB_ARRAY_TYPE = 0x8625;

- const GLenum VERTEX_ATTRIB_ARRAY_NORMALIZED = 0x886A;

- const GLenum VERTEX_ATTRIB_ARRAY_POINTER = 0x8645;

- const GLenum VERTEX_ATTRIB_ARRAY_BUFFER_BINDING = 0x889F;

- /* Shader Source */

- const GLenum COMPILE_STATUS = 0x8B81;

- const GLenum INFO_LOG_LENGTH = 0x8B84;

- const GLenum SHADER_SOURCE_LENGTH = 0x8B88;

- /* Shader Precision-Specified Types */

- const GLenum LOW_FLOAT = 0x8DF0;

- const GLenum MEDIUM_FLOAT = 0x8DF1;

- const GLenum HIGH_FLOAT = 0x8DF2;

- const GLenum LOW_INT = 0x8DF3;

- const GLenum MEDIUM_INT = 0x8DF4;

- const GLenum HIGH_INT = 0x8DF5;

- /* Framebuffer Object. */

- const GLenum FRAMEBUFFER = 0x8D40;

- const GLenum RENDERBUFFER = 0x8D41;

- const GLenum RGBA4 = 0x8056;

- const GLenum RGB5_A1 = 0x8057;

- const GLenum RGB565 = 0x8D62;

- const GLenum DEPTH_COMPONENT16 = 0x81A5;

- const GLenum STENCIL_INDEX = 0x1901;

- const GLenum STENCIL_INDEX8 = 0x8D48;

- const GLenum DEPTH_STENCIL = 0x84F9;

- const GLenum RENDERBUFFER_WIDTH = 0x8D42;

- const GLenum RENDERBUFFER_HEIGHT = 0x8D43;

- const GLenum RENDERBUFFER_INTERNAL_FORMAT = 0x8D44;

- const GLenum RENDERBUFFER_RED_SIZE = 0x8D50;

- const GLenum RENDERBUFFER_GREEN_SIZE = 0x8D51;

- const GLenum RENDERBUFFER_BLUE_SIZE = 0x8D52;

- const GLenum RENDERBUFFER_ALPHA_SIZE = 0x8D53;

- const GLenum RENDERBUFFER_DEPTH_SIZE = 0x8D54;

- const GLenum RENDERBUFFER_STENCIL_SIZE = 0x8D55;

- const GLenum FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE = 0x8CD0;

- const GLenum FRAMEBUFFER_ATTACHMENT_OBJECT_NAME = 0x8CD1;

- const GLenum FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL = 0x8CD2;

- const GLenum FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE = 0x8CD3;

- const GLenum COLOR_ATTACHMENT0 = 0x8CE0;

- const GLenum DEPTH_ATTACHMENT = 0x8D00;

- const GLenum STENCIL_ATTACHMENT = 0x8D20;

- const GLenum DEPTH_STENCIL_ATTACHMENT = 0x821A;

- const GLenum NONE = 0;

- const GLenum FRAMEBUFFER_COMPLETE = 0x8CD5;

- const GLenum FRAMEBUFFER_INCOMPLETE_ATTACHMENT = 0x8CD6;

- const GLenum FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT = 0x8CD7;

- const GLenum FRAMEBUFFER_INCOMPLETE_DIMENSIONS = 0x8CD9;

- const GLenum FRAMEBUFFER_UNSUPPORTED = 0x8CDD;

- const GLenum FRAMEBUFFER_BINDING = 0x8CA6;

- const GLenum RENDERBUFFER_BINDING = 0x8CA7;

- const GLenum MAX_RENDERBUFFER_SIZE = 0x84E8;

- const GLenum INVALID_FRAMEBUFFER_OPERATION = 0x0506;

- /* WebGL-specific enums */

- const GLenum UNPACK_FLIP_Y_WEBGL = 0x9240;

- const GLenum UNPACK_PREMULTIPLY_ALPHA_WEBGL = 0x9241;

- const GLenum CONTEXT_LOST_WEBGL = 0x9242;

- const GLenum UNPACK_COLORSPACE_CONVERSION_WEBGL = 0x9243;

- const GLenum BROWSER_DEFAULT_WEBGL = 0x9244;

- readonly attribute HTMLCanvasElement canvas;

- readonly attribute GLsizei drawingBufferWidth;

- readonly attribute GLsizei drawingBufferHeight;

- WebGLContextAttributes getContextAttributes();

- boolean isContextLost();

- DOMString[ ] getSupportedExtensions();

- object getExtension(DOMString name);

- void activeTexture(GLenum texture);

- void attachShader(WebGLProgram program, WebGLShader shader);

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

- void bindBuffer(GLenum target, WebGLBuffer buffer);

- void bindFramebuffer(GLenum target, WebGLFramebuffer framebuffer);

- void bindRenderbuffer(GLenum target, WebGLRenderbuffer renderbuffer);

- void bindTexture(GLenum target, WebGLTexture texture);

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

- void blendEquation(GLenum mode);

- void blendEquationSeparate(GLenum modeRGB, GLenum modeAlpha);

- void blendFunc(GLenum sfactor, GLenum dfactor);

- void blendFuncSeparate(GLenum srcRGB, GLenum dstRGB,

- GLenum srcAlpha, GLenum dstAlpha);

- void bufferData(GLenum target, GLsizei size, GLenum usage);

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

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

- void bufferSubData(GLenum target, GLsizeiptr offset, ArrayBufferView data);

- void bufferSubData(GLenum target, GLsizeiptr offset, ArrayBuffer data);

- GLenum checkFramebufferStatus(GLenum target);

- void clear(GLbitfield mask);

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

- void clearDepth(GLclampf depth);

- void clearStencil(GLint s);

- void colorMask(GLboolean red, GLboolean green, GLboolean blue, GLboolean alpha);

- void compileShader(WebGLShader shader);

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

- GLint x, GLint y, GLsizei width, GLsizei height,

- GLint border);

- void copyTexSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

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

- WebGLBuffer createBuffer();

- WebGLFramebuffer createFramebuffer();

- WebGLProgram createProgram();

- WebGLRenderbuffer createRenderbuffer();

- WebGLShader createShader(GLenum type);

- WebGLTexture createTexture();

- void cullFace(GLenum mode);

- void deleteBuffer(WebGLBuffer buffer);

- void deleteFramebuffer(WebGLFramebuffer framebuffer);

- void deleteProgram(WebGLProgram program);

- void deleteRenderbuffer(WebGLRenderbuffer renderbuffer);

- void deleteShader(WebGLShader shader);

- void deleteTexture(WebGLTexture texture);

- void depthFunc(GLenum func);

- void depthMask(GLboolean flag);

- void depthRange(GLclampf zNear, GLclampf zFar);

- void detachShader(WebGLProgram program, WebGLShader shader);

- void disable(GLenum cap);

- void disableVertexAttribArray(GLuint index);

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

- void drawElements(GLenum mode, GLsizei count, GLenum type, GLsizeiptr offset);

- void enable(GLenum cap);

- void enableVertexAttribArray(GLuint index);

- void finish();

- void flush();

- void framebufferRenderbuffer(GLenum target, GLenum attachment,

- GLenum renderbuffertarget,

- WebGLRenderbuffer renderbuffer);

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

- WebGLTexture texture, GLint level);

- void frontFace(GLenum mode);

- void generateMipmap(GLenum target);

- WebGLActiveInfo getActiveAttrib(WebGLProgram program, GLuint index);

- WebGLActiveInfo getActiveUniform(WebGLProgram program, GLuint index);

- WebGLShader[ ] getAttachedShaders(WebGLProgram program);

- GLint getAttribLocation(WebGLProgram program, DOMString name);

- any getParameter(GLenum pname);

- any getBufferParameter(GLenum target, GLenum pname);

- GLenum getError();

- any getFramebufferAttachmentParameter(GLenum target, GLenum attachment,

- GLenum pname);

- any getProgramParameter(WebGLProgram program, GLenum pname);

- DOMString getProgramInfoLog(WebGLProgram program);

- any getRenderbufferParameter(GLenum target, GLenum pname);

- any getShaderParameter(WebGLShader shader, GLenum pname);

- DOMString getShaderInfoLog(WebGLShader shader);

- DOMString getShaderSource(WebGLShader shader);

- any getTexParameter(GLenum target, GLenum pname);

- any getUniform(WebGLProgram program, WebGLUniformLocation location);

- WebGLUniformLocation getUniformLocation(WebGLProgram program, DOMString name);

- any getVertexAttrib(GLuint index, GLenum pname);

- GLsizeiptr getVertexAttribOffset(GLuint index, GLenum pname);

- void hint(GLenum target, GLenum mode);

- GLboolean isBuffer(WebGLBuffer buffer);

- GLboolean isEnabled(GLenum cap);

- GLboolean isFramebuffer(WebGLFramebuffer framebuffer);

- GLboolean isProgram(WebGLProgram program);

- GLboolean isRenderbuffer(WebGLRenderbuffer renderbuffer);

- GLboolean isShader(WebGLShader shader);

- GLboolean isTexture(WebGLTexture texture);

- void lineWidth(GLfloat width);

- void linkProgram(WebGLProgram program);

- void pixelStorei(GLenum pname, GLint param);

- void polygonOffset(GLfloat factor, GLfloat units);

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

- GLenum format, GLenum type, ArrayBufferView pixels);

- void renderbufferStorage(GLenum target, GLenum internalformat,

- GLsizei width, GLsizei height);

- void sampleCoverage(GLclampf value, GLboolean invert);

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

- void shaderSource(WebGLShader shader, DOMString source);

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

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

- void stencilMask(GLuint mask);

- void stencilMaskSeparate(GLenum face, GLuint mask);

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

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

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

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

- GLenum type, ArrayBufferView pixels);

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

- GLenum format, GLenum type, ImageData pixels);

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

- GLenum format, GLenum type, HTMLImageElement image);

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

- GLenum format, GLenum type, HTMLCanvasElement canvas);

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

- GLenum format, GLenum type, HTMLVideoElement video);

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

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

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

- GLsizei width, GLsizei height,

- GLenum format, GLenum type, ArrayBufferView pixels);

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

- GLenum format, GLenum type, ImageData pixels);

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

- GLenum format, GLenum type, HTMLImageElement image);

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

- GLenum format, GLenum type, HTMLCanvasElement canvas);

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

- GLenum format, GLenum type, HTMLVideoElement video);

- void uniform1f(WebGLUniformLocation location, GLfloat x);

- void uniform1fv(WebGLUniformLocation location, Float32Array v);

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

- void uniform1i(WebGLUniformLocation location, GLint x);

- void uniform1iv(WebGLUniformLocation location, Int32Array v);

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

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

- void uniform2fv(WebGLUniformLocation location, Float32Array v);

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

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

- void uniform2iv(WebGLUniformLocation location, Int32Array v);

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

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

- void uniform3fv(WebGLUniformLocation location, Float32Array v);

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

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

- void uniform3iv(WebGLUniformLocation location, Int32Array v);

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

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

- void uniform4fv(WebGLUniformLocation location, Float32Array v);

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

- void uniform4i(WebGLUniformLocation location, GLint x, GLint y, GLint z, GLint w);

- void uniform4iv(WebGLUniformLocation location, Int32Array v);

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

- void uniformMatrix2fv(WebGLUniformLocation location, GLboolean transpose,

- Float32Array value);

- void uniformMatrix2fv(WebGLUniformLocation location, GLboolean transpose,

- float[] value);

- void uniformMatrix3fv(WebGLUniformLocation location, GLboolean transpose,

- Float32Array value);

- void uniformMatrix3fv(WebGLUniformLocation location, GLboolean transpose,

- float[] value);

- void uniformMatrix4fv(WebGLUniformLocation location, GLboolean transpose,

- Float32Array value);

- void uniformMatrix4fv(WebGLUniformLocation location, GLboolean transpose,

- float[] value);

- void useProgram(WebGLProgram program);

- void validateProgram(WebGLProgram program);

- void vertexAttrib1f(GLuint indx, GLfloat x);

- void vertexAttrib1fv(GLuint indx, Float32Array values);

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

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

- void vertexAttrib2fv(GLuint indx, Float32Array values);

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

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

- void vertexAttrib3fv(GLuint indx, Float32Array values);

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

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

- void vertexAttrib4fv(GLuint indx, Float32Array values);

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

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

- GLboolean normalized, GLsizei stride, GLsizeiptr offset);

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

-};</pre>

-

- <h4>Attributes</h4>

- <p>

- The following attributes are available:

- </p>

- <dl class="methods">

- <dt>

- <code class=attribute-name>

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

- canvas

- </a>

- </code>

- of type <code>HTMLCanvasElement</code>

- <dd>

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

- <dt>

- <code class=attribute-name>

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

- drawingBufferWidth

- </a>

- </code>

- of type <code>GLsizei</code>

- <dd>

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

- <code>width</code> attribute of the <code>HTMLCanvasElement</code> if

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

- <dt>

- <code class=attribute-name>

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

- drawingBufferHeight

- </a>

- </code>

- of type <code>GLsizei</code>

- <dd>

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

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

- the implementation is unable to satisfy the requested width or height.

- </dl>

-

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

- <dl class="methods">

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

- <dd>

- Returns the WebGLContextAttributes describing the current drawing buffer.

- </dl>

-

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

- <p>

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

- group behave identically to their OpenGL counterparts unless otherwise noted.

- </p>

- <dl class="methods">

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.7, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glActiveTexture.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.6, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendColor.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.6, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendEquation.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.6, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendEquationSeparate.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.6, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendFunc.xml">man page</a>)</span>

- <dd>

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

- by WebGL.

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.6, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBlendFuncSeparate.xml">man page</a>)</span>

- <dd>

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

- by WebGL.

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClearColor.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClearDepthf.xml">man page</a>)</span>

- <dd>

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClearStencil.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glColorMask.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.5.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCullFace.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.5, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDepthFunc.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDepthMask.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §2.12.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDepthRangef.xml">man page</a>)</span>

- <dd>

- <code>zNear</code> and <code>zFar</code> values are clamped to the range 0 to 1 and

- <code>zNear</code> must be less than or equal to <code>zFar</code>; see

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

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

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

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

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.5.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFrontFace.xml">man page</a>)</span>

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

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

- (glGet OpenGL ES 2.0 man page)

- </a>

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

- (glGetString OpenGL ES 2.0 man page)

- </a>

- <dd>

- Return the value for the passed pname. The type returned is the natural type for the

- requested pname, as given in the following table:

- <table class="foo">

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

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

- <tr><td>ALIASED_LINE_WIDTH_RANGE</td><td>Float32Array (with 2 elements)</td></tr>

- <tr><td>ALIASED_POINT_SIZE_RANGE</td><td>Float32Array (with 2 elements)</td></tr>

- <tr><td>ALPHA_BITS</td><td>long</td></tr>

- <tr><td>ARRAY_BUFFER_BINDING</td><td>WebGLBuffer</td></tr>

- <tr><td>BLEND</td><td>boolean</td></tr>

- <tr><td>BLEND_COLOR</td><td>Float32Array (with 4 values)</td></tr>

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

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

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

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

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

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

- <tr><td>BLUE_BITS</td><td>long</td></tr>

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

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

- <tr><td>COMPRESSED_TEXTURE_FORMATS</td><td>null</td></tr>

- <tr><td>CULL_FACE</td><td>boolean</td></tr>

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

- <tr><td>CURRENT_PROGRAM</td><td>WebGLProgram</td></tr>

- <tr><td>DEPTH_BITS</td><td>long</td></tr>

- <tr><td>DEPTH_CLEAR_VALUE</td><td>float</td></tr>

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

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

- <tr><td>DEPTH_TEST</td><td>boolean</td></tr>

- <tr><td>DEPTH_WRITEMASK</td><td>boolean</td></tr>

- <tr><td>DITHER</td><td>boolean</td></tr>

- <tr><td>ELEMENT_ARRAY_BUFFER_BINDING</td><td>WebGLBuffer</td></tr>

- <tr><td>FRAMEBUFFER_BINDING</td><td>WebGLFramebuffer</td></tr>

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

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

- <tr><td>GREEN_BITS</td><td>long</td></tr>

- <tr><td>LINE_WIDTH</td><td>float</td></tr>

- <tr><td>MAX_COMBINED_TEXTURE_IMAGE_UNITS</td><td>long</td></tr>

- <tr><td>MAX_CUBE_MAP_TEXTURE_SIZE</td><td>long</td></tr>

- <tr><td>MAX_FRAGMENT_UNIFORM_VECTORS</td><td>long</td></tr>

- <tr><td>MAX_RENDERBUFFER_SIZE</td><td>long</td></tr>

- <tr><td>MAX_TEXTURE_IMAGE_UNITS</td><td>long</td></tr>

- <tr><td>MAX_TEXTURE_SIZE</td><td>long</td></tr>

- <tr><td>MAX_VARYING_VECTORS</td><td>long</td></tr>

- <tr><td>MAX_VERTEX_ATTRIBS</td><td>long</td></tr>

- <tr><td>MAX_VERTEX_TEXTURE_IMAGE_UNITS</td><td>long</td></tr>

- <tr><td>MAX_VERTEX_UNIFORM_VECTORS</td><td>long</td></tr>

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

- <tr><td>NUM_COMPRESSED_TEXTURE_FORMATS</td><td>long</td></tr>

- <tr><td>PACK_ALIGNMENT</td><td>long</td></tr>

- <tr><td>POLYGON_OFFSET_FACTOR</td><td>float</td></tr>

- <tr><td>POLYGON_OFFSET_FILL</td><td>boolean</td></tr>

- <tr><td>POLYGON_OFFSET_UNITS</td><td>float</td></tr>

- <tr><td>RED_BITS</td><td>long</td></tr>

- <tr><td>RENDERBUFFER_BINDING</td><td>WebGLRenderbuffer</td></tr>

- <tr><td>RENDERER</td><td>DOMString</td></tr>

- <tr><td>SAMPLE_BUFFERS</td><td>long</td></tr>

- <tr><td>SAMPLE_COVERAGE_INVERT</td><td>boolean</td></tr>

- <tr><td>SAMPLE_COVERAGE_VALUE</td><td>float</td></tr>

- <tr><td>SAMPLES</td><td>long</td></tr>

- <tr><td>SCISSOR_BOX</td><td>Int32Array (with 4 elements)</td></tr>

- <tr><td>SCISSOR_TEST</td><td>boolean</td></tr>

- <tr><td>SHADING_LANGUAGE_VERSION</td><td>DOMString</td></tr>

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

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

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

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

- <tr><td>STENCIL_BACK_REF</td><td>long</td></tr>

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

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

- <tr><td>STENCIL_BITS</td><td>long</td></tr>

- <tr><td>STENCIL_CLEAR_VALUE</td><td>long</td></tr>

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

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

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

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

- <tr><td>STENCIL_REF</td><td>long</td></tr>

- <tr><td>STENCIL_TEST</td><td>boolean</td></tr>

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

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

- <tr><td>SUBPIXEL_BITS</td><td>long</td></tr>

- <tr><td>TEXTURE_BINDING_2D</td><td>WebGLTexture</td></tr>

- <tr><td>TEXTURE_BINDING_CUBE_MAP</td><td>WebGLTexture</td></tr>

- <tr><td>UNPACK_ALIGNMENT</td><td>int</td></tr>

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

- <tr><td>UNPACK_FLIP_Y_WEBGL</td><td>boolean</td></tr>

- <tr><td>UNPACK_PREMULTIPLY_ALPHA_WEBGL</td><td>boolean</td></tr>

- <tr><td>VENDOR</td><td>DOMString</td></tr>

- <tr><td>VERSION</td><td>DOMString</td></tr>

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

- </table><br>

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

- <table>

- <tr><td>VERSION</td>

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

- <tr><td>SHADING_LANGUAGE_VERSION</td>

- <td>Returns a version or release number of the form <code>WebGL<space>GLSL<space>ES<space>1.0<space><vendor-specific information></code>.</td></tr>

- <tr><td>VENDOR</td>

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

- <tr><td>RENDERER</td>

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

- </table><br>

- <p>See <a href="#EXTENSION_QUERIES">Extension Queries</a> for information on querying the

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §2.5, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetError.xml">man page</a>)</span>

- <dd>

- See <a href="#WEBGLCONTEXTEVENT">WebGLContextEvent</a> for documentation of a

- WebGL-specific return value from getError.

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

- <span class="gl-spec">(OpenGL ES 2.0 §5.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glHint.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glIsEnabled.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glLineWidth.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.6.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glPixelStorei.xml">man page</a>)</span>

- <dd>

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

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

- <code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code>

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

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.5.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glPolygonOffset.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glSampleCoverage.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilFunc.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilFuncSeparate.xml">man page</a>)</span>

- <dd>

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

- on WebGL specific limitations to the allowable argument values.

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilMask.xml">man page</a>)</span>

- <dd>

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

- on WebGL specific limitations to the allowable mask values.

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilMaskSeparate.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilOp.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glStencilOpSeparate.xml">man page</a>)</span>

- </dl>

-

- <h4>Viewing and clipping</h4>

- <p>

- The viewport specifies the affine transformation of x and y from normalized device

- coordinates to window coordinates. The size of the drawing buffer is determined by

- the HTMLCanvasElement. The scissor box defines a rectangle which constrains drawing.

- When the scissor test is enabled only pixels that lie within the scissor box can

- be modified by drawing commands. When enabled drawing can only occur inside the

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

- is not enabled drawing can only occur inside the intersection of the viewport and

- canvas area.

- </p>

- <dl class="methods">

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.1.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glScissor.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §2.12.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glViewport.xml">man page</a>)</span>

- </dl>

-

- <h4>Buffer objects</h4>

- <p>

- Buffer objects (sometimes referred to as VBOs) hold vertex attribute data for the GLSL

- shaders.

- </p>

- <dl class="methods">

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

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindBuffer.xml">man page</a>)</span>

- <dd>

- Binds the given WebGLBuffer object to the given binding point (target), either

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

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

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

- buffer object to the other target will generate an <code>INVALID_OPERATION</code> error, and the

- current binding will remain untouched.

- <dt class="idl-code">void bufferData(GLenum target, GLsizei size, GLenum usage)

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBufferData.xml">man page</a>)</span>

- <dd>

- Set the size of the currently bound WebGLBuffer object for the passed target. The

- buffer is initialized to 0.

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBufferData.xml">man page</a>)</span></p>

- <dd>

- Set the size of the currently bound WebGLBuffer object for the passed target to the

- size of the passed data, then write the contents of data to the buffer object.

- <br><br>

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

- <dt><p class="idl-code">void bufferSubData(GLenum target, GLsizeiptr offset, ArrayBufferView data)</p>

- <p class="idl-code">void bufferSubData(GLenum target, GLsizeiptr offset, ArrayBuffer data)

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBufferSubData.xml">man page</a>)</span></p>

- <dd>

- For the WebGLBuffer object bound to the passed target write the passed data starting

- at the passed offset. If the data would be written past the end of the buffer object

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenBuffers.xml">glGenBuffers</a>)</span>

- <dd>

- Create a WebGLBuffer object and initialize it with a buffer object name as if by

- calling glGenBuffers.

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

- <span class="gl-spec">(OpenGL ES 2.0 §2.9, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteBuffers.xml">glDeleteBuffers</a>)</span>

- <dd>

- Delete the buffer object contained in the passed WebGLBuffer as if by calling

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

- Note that the buffer object will be deleted when the WebGLBuffer object is destroyed.

- This method merely gives the author greater control over when the buffer object is

- destroyed.

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

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.3, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetBufferParameteriv.xml">glGetBufferParameteriv</a>)</span>

- <dd>

- Return the value for the passed pname. The type returned is the natural type for the

- requested pname, as given in the following table:

- <table class="foo">

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

- <tr><td>BUFFER_SIZE</td><td>long</td></tr>

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

- </table>

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

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.6, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glIsBuffer.xml">man page</a>)</span>

- </dl>

-

- <h4>Framebuffer objects</h4>

- <p>

- Framebuffer objects provide an alternative rendering target to the drawing buffer. They

- are a collection of color, alpha, depth and stencil buffers and are often used to

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

- </p>

- <dl class="methods">

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindFramebuffer.xml">man page</a>)</span>

- <dd>

- Bind the given <code class="interface">WebGLFramebuffer</code> object to the given binding point

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

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

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

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.5, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCheckFramebufferStatus.xml">man page</a>)</span>

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.1, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenFramebuffers.xml">glGenFramebuffers</a>)</span>

- <dd>

- Create a WebGLFramebuffer object and initialize it with a framebuffer object name as if by

- calling glGenFramebuffers.

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.1, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteFramebuffers.xml">glDeleteFramebuffers</a>)</span>

- <dd>

- Delete the framebuffer object contained in the passed WebGLFramebuffer as if by calling

- glDeleteFramebuffers. If the framebuffer has already been deleted the call has no effect.

- Note that the framebuffer object will be deleted when the WebGLFramebuffer object is destroyed.

- This method merely gives the author greater control over when the framebuffer object is

- destroyed.

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

- GLenum renderbuffertarget,

- WebGLRenderbuffer renderbuffer)

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFramebufferRenderbuffer.xml">man page</a>)</span></dt>

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

- WebGLTexture texture, GLint level)

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFramebufferTexture2D.xml">man page</a>)</span>

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

- GLenum pname)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.3, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetFramebufferAttachmentParameteriv.xml">glGetFramebufferAttachmentParameteriv</a>)</span>

- <dd>

- Return the value for the passed pname given the passed target and attachment. The type

- returned is the natural type for the requested pname, as given in the following table:

- <table class="foo">

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

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

- <tr><td>FRAMEBUFFER_ATTACHMENT_OBJECT_NAME</td><td>WebGLRenderbuffer or WebGLTexture</td></tr>

- <tr><td>FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL</td><td>long</td></tr>

- <tr><td>FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE</td><td>long</td></tr>

- </table>

- <dt class="idl-code">GLboolean isFramebuffer(WebGLFramebuffer framebuffer)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.7, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glIsFramebuffer.xml">man page</a>)</span>

- <dd>

- Return true if the passed WebGLFramebuffer is valid and false otherwise.

- </dl>

-

- <h4>Renderbuffer objects</h4>

- <p>

- Renderbuffer objects are used to provide storage for the individual buffers used in a

- framebuffer object.

- </p>

- <dl class="methods">

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindRenderbuffer.xml">man page</a>)</span>

- <dd>

- Bind the given <code class="interface">WebGLRenderbuffer</code> object to the given binding point

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

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

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenRenderbuffers.xml">glGenRenderbuffers</a>)</span>

- <dd>

- Create a WebGLRenderbuffer object and initialize it with a renderbuffer object name as if by

- calling glGenRenderbuffers.

- <dt class="idl-code">void deleteRenderbuffer(WebGLRenderbuffer renderbuffer)

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteRenderbuffers.xml">glDeleteRenderbuffers</a>)</span>

- <dd>

- Delete the renderbuffer object contained in the passed WebGLRenderbuffer as if by calling

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

- Note that the renderbuffer object will be deleted when the WebGLRenderbuffer object is destroyed.

- This method merely gives the author greater control over when the renderbuffer object is

- destroyed.

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

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.3, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetRenderbufferParameteriv.xml">glGetRenderbufferParameteriv</a>)</span>

- <dd>

- Return the value for the passed pname given the passed target. The type returned is the natural

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

- <table class="foo">

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

- <tr><td>RENDERBUFFER_WIDTH</td><td>long</td></tr>

- <tr><td>RENDERBUFFER_HEIGHT</td><td>long</td></tr>

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

- <tr><td>RENDERBUFFER_RED_SIZE</td><td>long</td></tr>

- <tr><td>RENDERBUFFER_GREEN_SIZE</td><td>long</td></tr>

- <tr><td>RENDERBUFFER_BLUE_SIZE</td><td>long</td></tr>

- <tr><td>RENDERBUFFER_ALPHA_SIZE</td><td>long</td></tr>

- <tr><td>RENDERBUFFER_DEPTH_SIZE</td><td>long</td></tr>

- <tr><td>RENDERBUFFER_STENCIL_SIZE</td><td>long</td></tr>

- </table>

- <dt class="idl-code">GLboolean isRenderbuffer(WebGLRenderbuffer renderbuffer)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.7, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glIsRenderbuffer.xml">man page</a>)</span>

- <dd>

- Return true if the passed WebGLRenderbuffer is valid and false otherwise.

- <dt class="idl-code">void renderbufferStorage(GLenum target, GLenum internalformat,

- GLsizei width, GLsizei height)

- <span class="gl-spec">(OpenGL ES 2.0 §4.4.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glRenderbufferStorage.xml">man page</a>)</span>

- </dl>

-

- <h4>Texture objects</h4>

- <p>

- Texture objects provide storage and state for texturing operations. If no WebGLTexture is bound

- (e.g., passing null or 0 to bindTexture) then attempts to modify or query the texture object shall

- generate an <code>INVALID_OPERATION</code> error. This is indicated in the functions below.

- </p>

- <dl class="methods">

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.13, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindTexture.xml">man page</a>)</span>

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

- GLint x, GLint y, GLsizei width, GLsizei height,

- GLint border)

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCopyTexImage2D.xml">man page</a>)</span>

- <dd>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCopyTexSubImage2D.xml">man page</a>)</span>

- <dd>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.13, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenTextures.xml">man page</a>)</span>

- <dd>

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

- calling glGenTextures.

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.13, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteTextures.xml">man page</a>)</span>

- <dd>

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

- glDeleteTextures. If the texture has already been deleted the call has no effect.

- Note that the texture object will be deleted when the WebGLTexture object is destroyed.

- This method merely gives the author greater control over when the texture object is

- destroyed.

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.11, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGenerateMipmap.xml">man page</a>)</span>

- <dd>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetTexParameter.xml">man page</a>)</span>

- <dd>

- Return the value for the passed pname given the passed target. The type returned is the natural type for the

- requested pname, as given in the following table:

- <table class="foo">

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

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

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

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

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

- </table>

- <dd>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glIsTexture.xml">man page</a>)</span>

- <dd>

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

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

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

- GLenum type, ArrayBufferView pixels)

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexImage2D.xml">man page</a>)</span>

- <dd>

- If <code>pixels</code> is null, a buffer of sufficient size initialized to 0 is

- passed. <br><br>

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

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

- UNSIGNED_SHORT_5_6_5, UNSIGNED_SHORT_4_4_4_4, or UNSIGNED_SHORT_5_5_5_1, a Uint16Array

- must be supplied. If the types do not match, an INVALID_OPERATION error is generated.

- <br><br>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

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

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

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

- <p class="idl-code">void texImage2D(GLenum target, GLint level, GLenum internalformat,

- GLenum format, GLenum type, HTMLImageElement image)</p>

- <p class="idl-code">void texImage2D(GLenum target, GLint level, GLenum internalformat,

- GLenum format, GLenum type, HTMLCanvasElement canvas)</p>

- <p class="idl-code">void texImage2D(GLenum target, GLint level, GLenum internalformat,

- GLenum format, GLenum type, HTMLVideoElement video)

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexImage2D.xml">man page</a>)</span></p>

- <dd>

- Uploads the given element or image data to the currently bound WebGLTexture. <br><br>

- The source image data is conceptually first converted to the data type and format

- specified by the <em>format</em> and <em>type</em> arguments, and then transferred to

- the OpenGL implementation. If a packed pixel format is specified which would imply loss

- of bits of precision from the image data, this loss of precision must occur. <br><br>

- If the source image is an RGB or RGBA lossless image with 8 bits per channel, the

- browser guarantees that the full precision of all channels is preserved. <br><br>

- If the original image contains an alpha channel and the

- <code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code> pixel storage parameter is false, then the

- RGB values are guaranteed to never have been premultiplied by the alpha channel, whether

- those values are derived directly from the original file format or converted from some

- other color format. <br><br>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

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

- <dt class="idl-code">void texParameterf(GLenum target, GLenum pname, GLfloat param)

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexParameter.xml">man page</a>)</span>

- <dd>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexParameter.xml">man page</a>)</span>

- <dd>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

- <dt class="idl-code">void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

- GLsizei width, GLsizei height,

- GLenum format, GLenum type, ArrayBufferView pixels)

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexSubImage2D.xml">man page</a>)</span>

- <dd>

- See <a href="#TEXIMAGE2D">texImage2D</a> for restrictions on the <em>format</em>

- and <em>pixels</em> arguments. <br><br>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

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

- <dt><p class="idl-code">void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

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

- <p class="idl-code">void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

- GLenum format, GLenum type, HTMLImageElement image)</p>

- <p class="idl-code">void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

- GLenum format, GLenum type, HTMLCanvasElement canvas)</p>

- <p class="idl-code">void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,

- GLenum format, GLenum type, HTMLVideoElement video)

- <span class="gl-spec">(OpenGL ES 2.0 §3.7.2, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glTexSubImage2D.xml">man page</a>)</span></p>

- <dd>

- Updates a sub-rectangle of the currently bound WebGLTexture with the contents of the

- given element or image data. <br><br>

- See <a href="#TEXIMAGE2D_HTML">texImage2D</a> for the interpretation of

- the <em>format</em> and <em>type</em> arguments. <br><br>

- If an attempt is made to call this function with no WebGLTexture bound (see above), an

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

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

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

- </dl>

-

- <h4>Programs and Shaders</h4>

- <p>

- Rendering with OpenGL ES 2.0 requires the use of <i>shaders</i>, written in OpenGL ES's shading language, GLSL ES.

- Shaders must be loaded with a source string (shaderSource), compiled

- (compileShader) and attached to a <i>program</i> (attachShader) which must be linked

- (linkProgram) and then used (useProgram).

- </p>

- <dl class="methods">

- <dt class="idl-code">void attachShader(WebGLProgram program, WebGLShader shader)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glAttachShader.xml">man page</a>)</span>

- <dt class="idl-code">void bindAttribLocation(WebGLProgram program, GLuint index, DOMString name)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glBindAttribLocation.xml">man page</a>)</span>

- <dt class="idl-code">void compileShader(WebGLShader shader)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCompileShader.xml">man page</a>)</span>

- <dt class="idl-code">WebGLProgram createProgram()

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCreateProgram.xml">man page</a>)</span>

- <dd>

- Create a WebGLProgram object and initialize it with a program object name as if by

- calling glCreateProgram.

- <dt class="idl-code">WebGLShader createShader(type)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glCreateShader.xml">man page</a>)</span>

- <dd>

- Create a WebGLShader object and initialize it with a shader object name as if by

- calling glCreateShader.

- <dt class="idl-code">void deleteProgram(WebGLProgram program)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteProgram.xml">man page</a>)</span>

- <dd>

- Delete the program object contained in the passed WebGLProgram as if by calling

- glDeleteProgram. If the program has already been deleted the call has no effect.

- Note that the program object will be deleted when the WebGLProgram object is destroyed.

- This method merely gives the author greater control over when the program object is

- destroyed.

- <dt class="idl-code">void deleteShader(WebGLShader shader)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDeleteShader.xml">man page</a>)</span>

- <dd>

- Delete the shader object contained in the passed WebGLShader as if by calling

- glDeleteShader. If the shader has already been deleted the call has no effect.

- Note that the shader object will be deleted when the WebGLShader object is destroyed.

- This method merely gives the author greater control over when the shader object is

- destroyed.

- <dt class="idl-code">void detachShader(WebGLProgram program, WebGLShader shader)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDetachShader.xml">man page</a>)</span>

- <dt class="idl-code">WebGLShader[ ] getAttachedShaders(WebGLProgram program)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetAttachedShaders.xml">man page</a>)</span>

- <dd>

- Return the list of shaders attached to the passed program.

- <dt class="idl-code">any getProgramParameter(WebGLProgram program, GLenum pname)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetProgramiv.xml">man page</a>)</span>

- <dd>

- Return the value for the passed pname given the passed program. The type returned is the natural

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

- <table class="foo">

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

- <tr><td>DELETE_STATUS</td><td>boolean</td></tr>

- <tr><td>LINK_STATUS</td><td>boolean</td></tr>

- <tr><td>VALIDATE_STATUS</td><td>boolean</td></tr>

- <tr><td>INFO_LOG_LENGTH</td><td>long</td></tr>

- <tr><td>ATTACHED_SHADERS</td><td>long</td></tr>

- <tr><td>ACTIVE_ATTRIBUTES</td><td>long</td></tr>

- <tr><td>ACTIVE_ATTRIBUTE_MAX_LENGTH</td><td>long</td></tr>

- <tr><td>ACTIVE_UNIFORMS</td><td>long</td></tr>

- <tr><td>ACTIVE_UNIFORM_MAX_LENGTH</td><td>long</td></tr>

- </table>

- <dt class="idl-code">DOMString getProgramInfoLog(WebGLProgram program)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetProgramInfoLog.xml">man page</a>)</span>

- <dt class="idl-code">any getShaderParameter(WebGLShader shader, GLenum pname)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetShaderiv.xml">man page</a>)</span>

- <dd>

- Return the value for the passed pname given the passed shader. The type returned is the natural

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

- <table class="foo">

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

- <tr><td>SHADER_TYPE</td><td>unsigned long</td></tr>

- <tr><td>DELETE_STATUS</td><td>boolean</td></tr>

- <tr><td>COMPILE_STATUS</td><td>boolean</td></tr>

- <tr><td>INFO_LOG_LENGTH</td><td>long</td></tr>

- <tr><td>SHADER_SOURCE_LENGTH</td><td>long</td></tr>

- </table>

- <dt class="idl-code">DOMString getShaderInfoLog(WebGLShader shader)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetShaderInfoLog.xml">man page</a>)</span>

- <dt class="idl-code">DOMString getShaderSource(WebGLShader shader)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetShaderSource.xml">man page</a>)</span>

- <dt class="idl-code">GLboolean isProgram(WebGLProgram program)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glIsProgram.xml">man page</a>)</span>

- <dd>

- Return true if the passed WebGLProgram is valid and false otherwise.

- <dt class="idl-code">GLboolean isShader(WebGLShader shader)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glIsShader.xml">man page</a>)</span>

- <dd>

- Return true if the passed WebGLShader is valid and false otherwise.

- <dt class="idl-code">void linkProgram(WebGLProgram program)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glLinkProgram.xml">man page</a>)</span>

- <dt class="idl-code">void shaderSource(WebGLShader shader, DOMString source)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glShaderSource.xml">man page</a>)</span>

- <dt class="idl-code">void useProgram(WebGLProgram program)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUseProgram.xml">man page</a>)</span>

- <dt class="idl-code">void validateProgram(WebGLProgram program)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.5, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glValidateProgram.xml">man page</a>)</span>

- </dl>

-

- <h4>Uniforms and attributes</h4>

- <p>

- Values used by the shaders are passed in as uniform of vertex attributes.

- </p>

- <dl class="methods">

- <dt class="idl-code">void disableVertexAttribArray(GLuint index)

- <span class="gl-spec">(OpenGL ES 2.0 §2.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDisableVertexAttribArray.xml">man page</a>)</span>

- <dt class="idl-code">void enableVertexAttribArray(GLuint index)

- <span class="gl-spec">(OpenGL ES 2.0 §2.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glEnableVertexAttribArray.xml">man page</a>)</span>

- <dd>

- Enable the vertex attribute at <code>index</code> as an array. WebGL imposes additional

- rules beyond OpenGL ES 2.0 regarding enabled vertex attributes;

- see <a href="#ATTRIBS_AND_RANGE_CHECKING">Enabled Vertex Attributes and Range

- Checking</a>.

- <dt class="idl-code">WebGLActiveInfo getActiveAttrib(WebGLProgram program, GLuint index)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetActiveAttrib.xml">man page</a>)</span>

- <dd>

- Returns information about the size, type and name of the vertex attribute at the

- passed index of the passed program object.

- <dt class="idl-code">WebGLActiveInfo getActiveUniform(WebGLProgram program, GLuint index)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetActiveUniform.xml">man page</a>)</span>

- <dd>

- Returns information about the size, type and name of the uniform at the

- passed index of the passed program object.

- <dt class="idl-code">GLint getAttribLocation(WebGLProgram program, DOMString name)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetAttribLocation.xml">man page</a>)</span>

- <dt class="idl-code">any getUniform(WebGLProgram program, WebGLUniformLocation location)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetUniform.xml">man page</a>)</span>

- <dd>

- Return the uniform value at the passed location in the passed program. The type returned is

- dependent on the uniform type, as shown in the following table:

- <table class="foo">

- <tr><th>uniform type</th><th>returned type</th></tr>

- <tr><td>boolean</td><td>boolean</td></tr>

- <tr><td>int</td><td>long</td></tr>

- <tr><td>float</td><td>float</td></tr>

- <tr><td>vec2</td><td>Float32Array (with 2 elements)</td></tr>

- <tr><td>ivec2</td><td>Int32Array (with 2 elements)</td></tr>

- <tr><td>bvec2</td><td>boolean[] (with 2 elements)</td></tr>

- <tr><td>vec3</td><td>Float32Array (with 3 elements)</td></tr>

- <tr><td>ivec3</td><td>Int32Array (with 3 elements)</td></tr>

- <tr><td>bvec3</td><td>boolean[] (with 3 elements)</td></tr>

- <tr><td>vec4</td><td>Float32Array (with 4 elements)</td></tr>

- <tr><td>ivec4</td><td>Int32Array (with 4 elements)</td></tr>

- <tr><td>bvec4</td><td>boolean[] (with 4 elements)</td></tr>

- <tr><td>mat2</td><td>Float32Array (with 4 elements)</td></tr>

- <tr><td>mat3</td><td>Float32Array (with 9 elements)</td></tr>

- <tr><td>mat4</td><td>Float32Array (with 16 elements)</td></tr>

- </table>

- <dt class="idl-code">WebGLUniformLocation getUniformLocation(WebGLProgram program, DOMString name)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetUniformLocation.xml">man page</a>)</span>

- <dd>

- Return a WebGLUniformLocation object that represents the location of a specific uniform variable

- within a program object. The return value is null if name does not correspond to an active uniform

- variable in the passed program.

- <dt class="idl-code">any getVertexAttrib(GLuint index, GLenum pname)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetVertexAttrib.xml">man page</a>)</span>

- <dd>

- Return the information requested in pname about the vertex attribute at the passed index. The

- type returned is dependent on the information requested, as shown in the following table:

- <table class="foo">

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

- <tr><td>VERTEX_ATTRIB_ARRAY_BUFFER_BINDING</td><td>WebGLBuffer</td></tr>

- <tr><td>VERTEX_ATTRIB_ARRAY_ENABLED</td><td>boolean</td></tr>

- <tr><td>VERTEX_ATTRIB_ARRAY_SIZE</td><td>long</td></tr>

- <tr><td>VERTEX_ATTRIB_ARRAY_STRIDE</td><td>long</td></tr>

- <tr><td>VERTEX_ATTRIB_ARRAY_TYPE</td><td>unsigned long</td></tr>

- <tr><td>VERTEX_ATTRIB_ARRAY_NORMALIZED</td><td>boolean</td></tr>

- <tr><td>CURRENT_VERTEX_ATTRIB</td><td>Float32Array (with 4 elements)</td></tr>

- </table>

- <dt class="idl-code">GLsizeiptr getVertexAttribOffset(GLuint index, GLenum pname)

- <span class="gl-spec">(OpenGL ES 2.0 §6.1.8, similar to <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glGetVertexAttribPointerv.xml">man page</a>)</span>

- <dt><p class="idl-code">void uniform[1234][fi](WebGLUniformLocation location, ...)</p>

- <p class="idl-code">void uniform[1234][fi]v(WebGLUniformLocation location, ...)

- <p class="idl-code">void uniformMatrix[234]fv(WebGLUniformLocation location, GLboolean transpose, ...)

- <span class="gl-spec">(OpenGL ES 2.0 §2.10.4, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glUniform.xml">man page</a>)</span></p>

- <dd>

- Each of the uniform* functions above sets the specified uniform or uniforms to the

- values provided. If the passed <code>location</code> is not null and was not obtained

- from the currently used program via an earlier call to <code>getUniformLocation</code>,

- an <code>INVALID_OPERATION</code> error will be generated. If the passed

- <code>location</code> is null, the data passed in will be silently ignored and

- no uniform variables will be changed.

- <dt><p class="idl-code">void vertexAttrib[1234]f(GLuint indx, ...)</p>

- <p class="idl-code">void vertexAttrib[1234]fv(GLuint indx, ...)

- <span class="gl-spec">(OpenGL ES 2.0 §2.7, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttrib.xml">man page</a>)</span></p>

- <dd>

- Sets the vertex attribute at the passed index to the given constant value. Values set via the

- <code>vertexAttrib</code> are guaranteed to be returned from the <code>getVertexAttrib</code> function

- with the <code>CURRENT_VERTEX_ATTRIB</code> param, even if there have been intervening calls to

- <code>drawArrays</code> or <code>drawElements</code>.

- <dt class="idl-code">void vertexAttribPointer(GLuint indx, GLint size, GLenum type,

- GLboolean normalized, GLsizei stride, GLsizeiptr offset)

- <span class="gl-spec">(OpenGL ES 2.0 §2.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glVertexAttribPointer.xml">man page</a>)</span>

- <dd>

- Assign the WebGLBuffer object currently bound to the ARRAY_BUFFER target to the vertex

- attribute at the passed index. Size is number of components per attribute. Stride and

- offset are in units of bytes. Passed stride and offset must be appropriate for the

- passed type and size or an <code>INVALID_VALUE</code> error will be

- generated; see <a href="#BUFFER_OFFSET_AND_STRIDE">Buffer Offset and Stride

- Requirements</a>. If no WebGLBuffer is bound to the ARRAY_BUFFER target,

- an <code>INVALID_OPERATION</code> error will be generated. In WebGL, the maximum

- supported stride is 255; see <a href="#VERTEX_STRIDE"> Vertex Attribute Data Stride</a>.

- </dl>

-

- <h4>Writing to the drawing buffer</h4>

- <p>

- OpenGL ES 2.0 has 3 calls which can render to the drawing buffer: <code>clear</code>,

- <code>drawArrays</code> and <code>drawElements</code>. Furthermore rendering can

- be directed to the drawing buffer or to a Framebuffer object. When rendering is

- directed to the drawing buffer, making any of the 3 rendering calls shall

- cause the drawing buffer to be presented to the HTML page compositor at the start

- of the next compositing operation.

- </p>

- <dl class="methods">

- <dt class="idl-code">void clear(GLbitfield mask)

- <span class="gl-spec">(OpenGL ES 2.0 §4.2.3, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glClear.xml">man page</a>)</span>

- <dt class="idl-code">void drawArrays(GLenum mode, GLint first, GLsizei count)

- <span class="gl-spec">(OpenGL ES 2.0 §2.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDrawArrays.xml">man page</a>)</span>

- <dd>

- If <em>first</em> is negative, an <code>INVALID_VALUE</code> error will be generated.

- <dt class="idl-code">void drawElements(GLenum mode, GLsizei count, GLenum type, GLsizeiptr offset)

- <span class="gl-spec">(OpenGL ES 2.0 §2.8, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glDrawElements.xml">man page</a>)</span>

- <dd>

- Draw using the currently bound element array buffer. The given offset is in bytes, and

- must be a valid multiple of the size of the given type or an <code>INVALID_VALUE</code>

- error will be generated; see <a href="#BUFFER_OFFSET_AND_STRIDE">Buffer Offset and Stride

- Requirements</a>. If <code>count</code> is greater than zero, then a non-null

- <code>WebGLBuffer</code> must be bound to the <code>ELEMENT_ARRAY_BUFFER</code> binding

- point or an <code>INVALID_OPERATION</code> error will be generated.<br><br>

- WebGL performs additional error checking beyond that specified in OpenGL ES 2.0 during

- calls to <code>drawArrays</code>

- and <code>drawElements</code>. See <a href="#ATTRIBS_AND_RANGE_CHECKING">Enabled Vertex

- Attributes and Range Checking</a>.

- <dt class="idl-code">void finish()

- <span class="gl-spec">(OpenGL ES 2.0 §5.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFinish.xml">man page</a>)</span>

- <dt class="idl-code">void flush()

- <span class="gl-spec">(OpenGL ES 2.0 §5.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glFlush.xml">man page</a>)</span>

- </dl>

-

- <h4><a name="readpixels">Reading back pixels</a></h4>

- <p>

- Pixels in the current framebuffer can be read back into an ArrayBufferView object.

- </p>

- <dl class="methods">

- <dt class="idl-code">void readPixels(GLint x, GLint y, GLsizei width, GLsizei height,

- GLenum format, GLenum type, ArrayBufferView pixels)

- <span class="gl-spec">(OpenGL ES 2.0 §4.3.1, <a href="http://www.khronos.org/opengles/sdk/2.0/docs/man/glReadPixels.xml">man page</a>)</span>

- <dd>

- Fills <code>pixels</code> with the pixel data in the specified rectangle of the frame

- buffer. The data returned from readPixels must be up-to-date as of the most recently

- sent drawing command.

- <br><br>

- The type of <code>pixels</code> must match the type of the data to be read. For example,

- if it is UNSIGNED_BYTE, a Uint8Array must be supplied; if it is UNSIGNED_SHORT_5_6_5,

- UNSIGNED_SHORT_4_4_4_4, or UNSIGNED_SHORT_5_5_5_1, a Uint16Array must be supplied. If

- the types do not match, an INVALID_OPERATION error is generated.

- <br><br>

- The following are the allowed format and type combinations:

- <table class="foo">

- <tr><th>format</th><th>type</th></tr>

- <tr><td>RGBA</td><td>UNSIGNED_BYTE</td></tr>

- </table>

- If <code>pixels</code> is null, an INVALID_VALUE error is generated. If

- <code>pixels</code> is non-null, but is not large enough to retrieve all of the pixels

- in the specified rectangle taking into account pixel store modes, an INVALID_OPERATION

- value is generated.

- <br><br>

- For any pixel lying outside the frame buffer, the value read contains 0 in all channels.

- <br><br>

- </dl>

-

- <h4>Detecting context lost events</h4>

- <p>

- Occurrences such as power events on mobile devices may cause the WebGL rendering context to

- be lost at any time and require the application to rebuild it;

- see <a href="#WEBGLCONTEXTEVENT">WebGLContextEvent</a> for more details. The

- following method assists in detecting context lost events.

- </p>

- <dl class="methods">

- <dt class="idl-code">boolean isContextLost()

- <dd>

- Returns true if the context is in the lost state.

- </dl>

-

- <h4>Detecting and enabling extensions</h4>

- <p>

- An implementation of WebGL must not support any additional parameters, constants or functions

- without first enabling that functionality through the extension mechanism. The

- <code>getSupportedExtensions</code> function returns an array of the extension strings supported

- by this implementation. Extension strings are case-insensitive. An extension is enabled by

- passing one of those strings to the <code>getExtension</code> function. This call returns an

- object which contains any constants or functions defined by that extension. The definition of

- that object is specific to the extension and must be defined by the extension specification.

- </p>

- <p>

- Once an extension is enabled, no mechanism is provided to disable it. Multiple calls to

- <code>getExtension</code> with the same extension string shall return the same object. An

- attempt to use any features of an extension without first calling getExtension to enable it

- must generate an appropriate GL error and must not make use of the feature.

- </p>

- <p>

- This specification does not define any extensions. A separate <a href="#refsREGISTRY">WebGL

- extension registry</a> defines extensions that may be supported by a particular WebGL

- implementation.

- </p>

- <dl class="methods">

- <dt class="idl-code">DOMString[ ] getSupportedExtensions()

- <dd>

- Returns an array of all the supported extension strings. Any string in this list, when

- passed to <code>getExtension</code> must return a valid object. Any other string passed to

- <code>getExtension</code> must return null.

- <dt class="idl-code">object getExtension(DOMString name)

- <dd>

- Returns an object if the passed extension is supported, or null if not. The object

- returned from <code>getExtension</code> contains any constants or functions used by the

- extension, if any. A returned object may have no constants or functions if the extension does

- not define any, but a unique object must still be returned. That object is used to indicate

- that the extension has been enabled.

- </dl>

-

- <h3><a name="WEBGLCONTEXTEVENT">WebGLContextEvent</a></h3>

- <p>

- WebGL generates a WebGLContextEvent event in response to a status change to the WebGL rendering context

- associated with the HTMLCanvasElement which has a listener for this event. Events are sent using

- the <a href="http://www.w3.org/TR/DOM-Level-2-Events/events.html">DOM Event System</a>. Event types can

- include the loss or restoration of state, or the inability to create a context.

- </p>

- <pre class="idl">

-interface <dfn id="WebGLContextLostEvent">WebGLContextEvent</dfn> : Event {

- readonly attribute DOMString statusMessage;

- void initWebGLContextEvent(DOMString typeArg,

- boolean canBubbleArg,

- boolean cancelableArg,

- DOMString statusMessageArg);

-};</pre>

- <h4>Attributes</h4>

- <p>

- The following attributes are available:

- </p>

- <dl class="methods">

- <dt><span class="prop-name"><code>statusMessage</code></span> of type <code>DOMString</code>

- <dd>

- A string containing additional information, or the empty string if no additional information

- is available.

- </dl>

- <h4>Methods</h4>

- <p>

- The following methods are available:

- </p>

- <dl class="methods">

- <dt class="idl-code">void initWebGLContextEvent(DOMString typeArg, boolean canBubbleArg, boolean cancelableArg,

- DOMString statusMessageArg)

- <dd>

- Initialize the event created through the

- <a href="http://www.w3.org/TR/DOM-Level-2-Events/events.html#Events-Event">Event</a>

- interface. This method may only be called before the event has been dispatched via

- the <code>dispatchEvent</code> method, though it may be called multiple times during

- that phase if necessary. If called multiple times, the final invocation takes

- precedence.

- <P>

- <b>Parameters</b>

- <dl>

- <dt><code>typeArg</code> of type <code>DOMString</code>

- <dd>Specifies the event type (see below).

- <dt><code>canBubbleArg</code> of type <code>boolean</code>

- <dd>Specifies whether or not the event can bubble.

- <dt><code>cancelableArg</code> of type <code>boolean</code>

- <dd>Specifies whether or not the event can be canceled.

- <dt><code>statusMessageArg</code> of type <code>DOMString</code>

- <dd>A string containing additional information, or the empty string if no additional information is available.

- </dl>

- <b>No Return Value</b><br>

- <b>No Exceptions</b><br>

- </dl>

- <h4>Event Types</h4>

- <dl class="methods">

- <dt class="idl-code">webglcontextlost

- <dd>

- This event occurs when some system activity external to WebGL causes the rendering context

- associated with the HTMLCanvasElement receiving the event to lose all of its state. When this

- event type is delivered, the associated context is in a "lost" state. While the context is

- in the lost state:

- <ul>

- <li> The context's <code>isContextLost</code> method returns <code>true</code>.<br>

- <li> All methods returning <code>void</code> return immediately.<br>

- <li> All methods returning nullable values or <code>any</code> return <code>null</code>.<br>

- <li> <code>checkFramebufferStatus</code> returns <code>FRAMEBUFFER_UNSUPPORTED</code>.<br>

- <li> <code>getAttribLocation</code> returns <code>-1</code>.<br>

- <li> <code>getError</code> returns <code>CONTEXT_LOST_WEBGL</code> the first time it is

- called while the context is lost. Afterward it will return <code>NO_ERROR</code> until

- the context has been restored.<br>

- <li> <code>getVertexAttribOffset</code> returns <code>0</code>.<br>

- <li> All <code>is</code> queries return <code>false</code>.<br>

- </ul>

- <p>

- See the <code>webglcontextrestored</code> event type for information on

- resuming rendering after the context has been lost.

- <p><p>

- The <code>statusMessage</code> attribute is always the empty string for this event.

- </dl>

- <dl class="methods">

- <dt class="idl-code">webglcontextrestored

- <dd>

- This event occurs when the WebGL implementation determines that a previously lost context can

- be restored. The system only restores the context if a handler for the

- <code>webglcontextrestored</code> event is installed on the HTMLCanvasElement associated with

- the context.

- <p><p>

- Once the context is restored, WebGL resources such as textures and buffers that were created

- before the context was lost are no longer valid. The application must reinitialize the

- context's state and recreate all such resources.

- <p><p>

- The <code>statusMessage</code> attribute is always the empty string for this event.

- </dl>

- <dl class="methods">

- <dt class="idl-code">webglcontextcreationerror

- <dd>

- This event occurs in response to a call to <code>getContext()</code> on the HTMLCanvasElement

- receiving the event, when some error occurs during that call. When such an error occurs

- the <code>getContext()</code> returns with a <code>null</code> value. Later, at the normal

- event delivery time, this event is delivered with the details of the failure. If the

- HTMLCanvasElement is listening for this event, it will be delivered whenever

- <code>getContext()</code> returns <code>null</code>.

- <p>

- The <code>statusMessage</code> attribute may contain a platform dependent string about the nature

- of the failure.

- </dl>

- <div class="example">

- The following ECMAScript example shows how to register event listeners on a Canvas called

- <code>canvas1</code> which will receive context lost and restored events and restart the

- application. For completeness, it illustrates how an application performing asynchronous image

- loading would handle a context lost event at an arbitrary point in time.

- <pre>

-window.onload = init;

-var g_gl;

-var g_canvas;

-var g_intervalId;

-var g_images = [];

-var g_imgURLs = [

- "someimage.jpg",

- "someotherimage.jpg",

- "yetanotherimage.png"

-];

-function init() {

- g_canvas = document.getElementById("canvas1");

- g_canvas.addEventListener("webglcontextlost", contextLostHandler, false);

- g_canvas.addEventListener("webglcontextrestored", contextRestoredHandler, false);

- g_gl = canvas.getContext("webgl");

- for (var ii = 0; ii < g_imgURLs.length; ++ii) {

- // Create an image tag.

- var image = document.createElement('img');

- // Create a texture for this image.

- image.texture = g_gl.createTexture();

- // Mark the image as not loaded.

- image.loaded = false;

- // Setup a load callback.

- image.onload = (function(image) {

- return function() {

- imageLoadedHandler(image);

- };

- }(image));

- // Start the image loading.

- image.src = g_imgURLs[ii];

- // Remember the image.

- g_images.push(image);

- }

- g_intervalId = window.setInterval(renderHandler, 1000/60);

-function renderHandler() {

- // draw with textures.

- // ...

-function imageLoadedHandler(image) {

- // Mark the image as loaded.

- image.loaded = true;

- // Copy the image to the texture.

- updateTexture(image);

-function updateTexture(image) {

- if (!g_gl.isContextLost() && image.loaded) {

- g_gl.bindTexture(g_gl.TEXTURE_2D, image.texture);

- g_gl.texImage2D(g_gl.TEXTURE_2D, 0, image);

- }

-function contextLostHandler() {

- // stop rendering.

- window.clearInterval(g_internvalId);

-function contextRestoredHandler() {

- // create new textures for all images and restore their contents.

- for (var ii = 0; ii < g_images.length; ++ii) {

- g_images[ii].texture = g_gl.createTexture();

- updateTexture(g_images[ii]);

- }

- // Start rendering again.

- g_intervalId = window.setInterval(renderHandler, 1000/60);

- </pre>

- </div>

-

- <h2><a name="webgl_gl_differences">Differences Between WebGL and OpenGL ES 2.0</a></h2>

-<p>

-This section describes changes made to the WebGL API relative to the OpenGL ES 2.0 API to improve

-portability across various operating systems and devices.

-</p>

- <h3>Buffer Object Binding</h3>

-<p>

-In the WebGL API, a given buffer object may only be bound to one of the <code>ARRAY_BUFFER</code> or

-<code>ELEMENT_ARRAY_BUFFER</code> binding points in its lifetime. This restriction implies that a

-given buffer object may contain either vertices or indices, but not both.

-</p>

-<p>

-The type of a WebGLBuffer is initialized the first time it is passed as an argument

-to <code>bindBuffer</code>. A subsequent call to <code>bindBuffer</code> which attempts to bind the

-same WebGLBuffer to the other binding point will generate an <code>INVALID_OPERATION</code> error, and

-the state of the binding point will remain untouched.

-</p>

- <h3>No Client Side Arrays</h3>

-<p>

-The WebGL API does not support client-side arrays. If <code>vertexAttribPointer</code> is called

-without a <code>WebGLBuffer</code> bound to the <code>ARRAY_BUFFER</code> binding point,

-an <code>INVALID_OPERATION</code> error is generated. If <code>drawElements</code> is called with

-a <code>count</code> greater than zero, and no <code>WebGLBuffer</code> is bound to

-the <code>ELEMENT_ARRAY_BUFFER</code> binding point, an <code>INVALID_OPERATION</code> error is

-generated.

-</p>

- <h3><a name="BUFFER_OFFSET_AND_STRIDE">Buffer Offset and Stride Requirements</a></h3>

-<p>

-The <code>offset</code> arguments to <code>drawElements</code> and <code>vertexAttribPointer</code>,

-and the <code>stride</code> argument to <code>vertexAttribPointer</code>, must be a multiple of the

-size of the data type passed to the call, or an <code>INVALID_OPERATION</code> error is generated.

-</p>

- <h3><a name="ATTRIBS_AND_RANGE_CHECKING">Enabled Vertex Attributes and Range Checking</a></h3>

-<p>

-If a vertex attribute is enabled as an array via <code>enableVertexAttribArray</code> but no buffer

-is bound to that attribute via <code>bindBuffer</code> and <code>vertexAttribPointer</code>, then

-calls to <code>drawArrays</code> or <code>drawElements</code> will generate an

-<code>INVALID_OPERATION</code> error.

-</p>

-<p>

-If a vertex attribute is enabled as an array, a buffer is bound to that attribute, and the attribute

-is consumed by the current program, then calls to <code>drawArrays</code>

-and <code>drawElements</code> will verify that each referenced vertex lies within the storage of the

-bound buffer. If the range specified in <code>drawArrays</code> or any referenced index

-in <code>drawElements</code> lies outside the storage of the bound buffer, an INVALID_OPERATION

-error is generated and no geometry is drawn.

-</p>

-<p>

-If a vertex attribute is enabled as an array, a buffer is bound to that attribute, but the attribute

-is not consumed by the current program, then regardless of the size of the bound buffer, it will not

-cause any error to be generated during a call to <code>drawArrays</code>

-or <code>drawElements</code>.

-</p>

- <h3>Framebuffer Object Attachments</h3>

-<p>

-WebGL adds the <code>DEPTH_STENCIL_ATTACHMENT</code> framebuffer object attachment point and

-the <code>DEPTH_STENCIL</code> renderbuffer internal format. To attach both depth and stencil

-buffers to a framebuffer object, call <code>renderbufferStorage</code> with

-the <code>DEPTH_STENCIL</code> internal format, and then call <code>framebufferRenderbuffer</code>

-with the <code>DEPTH_STENCIL_ATTACHMENT</code> attachment point.

-</p>

-<p>

-A renderbuffer attached to the <code>DEPTH_ATTACHMENT</code> attachment point must be allocated with

-the <code>DEPTH_COMPONENT16</code> internal format. A renderbuffer attached to

-the <code>STENCIL_ATTACHMENT</code> attachment point must be allocated with

-the <code>STENCIL_INDEX8</code> internal format. A renderbuffer attached to

-the <code>DEPTH_STENCIL_ATTACHMENT</code> attachment point must be allocated with

-the <code>DEPTH_STENCIL</code> internal format.

-</p>

-<p>

-In the WebGL API, it is an error to concurrently attach renderbuffers to the following combinations

-of attachment points:

-<ul>

-<li> <code>DEPTH_ATTACHMENT + DEPTH_STENCIL_ATTACHMENT</code>

-<li> <code>STENCIL_ATTACHMENT + DEPTH_STENCIL_ATTACHMENT</code>

-<li> <code>DEPTH_ATTACHMENT + STENCIL_ATTACHMENT</code>

-</ul>

-If any of the constraints above are violated, then:

-<ul>

-<li> <code>checkFramebufferStatus</code> must return <code>FRAMEBUFFER_UNSUPPORTED</code>.

-<li> The following calls, which either modify or read the framebuffer, must generate

- an <code>INVALID_FRAMEBUFFER_OPERATION</code> error and return early, leaving the contents of

- the framebuffer, destination texture or destination memory untouched.

- <ul>

- <li> clear

- <li> copyTexImage2D

- <li> copyTexSubImage2D

- <li> drawArrays

- <li> drawElements

- <li> readPixels

- </ul>

-</ul>

-<h3><a name="PIXEL_STORAGE_PARAMETERS">Pixel Storage Parameters</a></h3>

-<p>

-The WebGL API supports the following additional parameters to <code>pixelStorei</code>.

-<dl>

-<dt><code>UNPACK_FLIP_Y_WEBGL</code> of type <code>boolean</code>

-<dd>If set, then during any subsequent calls to <code>texImage2D</code> or

-<code>texSubImage2D</code>, the source data is flipped along the vertical axis, so that conceptually

-the last row is the first one transferred. The default value is <code>false</code>. Any non-zero

-value is interpreted as <code>true</code>.

-<dt><code>UNPACK_PREMULTIPLY_ALPHA_WEBGL</code> of type <code>boolean</code>

-<dd>If set, then during any subsequent calls to <code>texImage2D</code>

-or <code>texSubImage2D</code>, the alpha channel of the source data, if present, is multiplied into

-the color channels during the data transfer. The default value is <code>false</code>. Any non-zero

-value is interpreted as <code>true</code>.

-<dt><code>UNPACK_COLORSPACE_CONVERSION_WEBGL</code> of type <code>unsigned long</code>

-<dd>If set to <code>BROWSER_DEFAULT_WEBGL</code>, then the browser's default colorspace conversion

-is applied during subsequent <code>texImage2D</code> and <code>texSubImage2D</code> calls

-taking <code>HTMLImageElement</code>. The precise conversions may be specific to both the browser

-and file type. If set to <code>NONE</code>, no colorspace conversion is applied. The default value

-is <code>BROWSER_DEFAULT_WEBGL</code>.

-</dl>

-<h3><a name="STENCIL_SEPARATE_LIMIT">Stencil Separate Mask and Reference Value</a></h3>

-<p>

-In the WebGL API it is illegal to specify a different mask or reference value for front facing and

-back facing triangles in stencil operations. A call to <code>drawArrays</code>

-or <code>drawElements</code> will generate an <code>INVALID_OPERATION</code> error if:

-<ul>

-<li> <code>STENCIL_WRITEMASK</code> != <code>STENCIL_BACK_WRITEMASK</code> (as specified by <code>stencilMaskSeparate</code> for the <code>mask</code> parameter associated with the FRONT and BACK values of <code>face</code>, respectively)

-<li> <code>STENCIL_VALUE_MASK</code> != <code>STENCIL_BACK_VALUE_MASK</code> (as specified by <code>stencilFuncSeparate</code> for the <code>mask</code> parameter associated with the FRONT and BACK values of <code>face</code>, respectively)

-<li> <code>STENCIL_REF</code> != <code>STENCIL_BACK_REF</code> (as specified by <code>stencilFuncSeparate</code> for the <code>ref</code> parameter associated with the FRONT and BACK values of <code>face</code>, respectively)

-</ul>

-</p>

- <h3><a name="VERTEX_STRIDE">Vertex Attribute Data Stride</a></h3>

-<p>

-The WebGL API supports vertex attribute data strides up to 255 bytes. A call to

-<code>vertexAttribPointer</code> will generate an <code>INVALID_VALUE</code> error if the value for

-the stride parameter exceeds 255.

-</p>

- <h3><a name="VIEWPORT_DEPTH_RANGE">Viewport Depth Range</a></h3>

-<p>

-The WebGL API does not support depth ranges with where the near plane is mapped to a value greater

-than that of the far plane. A call to <code>depthRange</code> will generate an

-<code>INVALID_OPERATION</code> error if <code>zNear</code> is greater than <code>zFar</code>.

-</p>

- <h3><a name="CONSTANT_COLOR_BLEND">Blending With Constant Color</a></h3>

-<p>

-In the WebGL API, constant color and constant alpha cannot be used together as source and

-destination factors in the blend function. A call to <code>blendFunc</code> will generate an

-<code>INVALID_OPERATION</code> error if one of the two factors is set to <code>CONSTANT_COLOR</code>

-or <code>ONE_MINUS_CONSTANT_COLOR</code> and the other to <code>CONSTANT_ALPHA</code> or

-<code>ONE_MINUS_CONSTANT_ALPHA</code>. A call to <code>blendFuncSeparate</code> will generate an

-<code>INVALID_OPERATION</code> error if <code>srcRGB</code> is set to <code>CONSTANT_COLOR</code>

-or <code>ONE_MINUS_CONSTANT_COLOR</code> and <code>dstRGB</code> is set to <code>CONSTANT_ALPHA</code> or

-<code>ONE_MINUS_CONSTANT_ALPHA</code> or vice versa.

-</p>

- <h3>Fixed point support</h3>

-The WebGL API does not support the <code>GL_FIXED</code> data type.

- <h3>GLSL Constructs</h3>

-<p>

-Per <a href="#SUPPORTED_GLSL_CONSTRUCTS">Supported GLSL Constructs</a>, identifiers starting with

-"webgl_" and "_webgl_" are reserved for use by WebGL.

-</p>

- <h3><a name="EXTENSION_QUERIES">Extension Queries</a></h3>

-<p>

-In the OpenGL ES 2.0 API, the available extensions are determined by calling

-<code>glGetString(GL_EXTENSIONS)</code>, which returns a space-separated list of extension strings.

-In the WebGL API, the <code>EXTENSIONS</code> enumerant has been removed.

-Instead, <code>getSupportedExtensions</code> must be called to determine the set of available

-extensions.

-</p>

- <h3><a name="IMPLEMENTATION_READ_FORMAT">Implementation Color Read Format and Type</a></h3>

-<p>

- In the OpenGL ES 2.0 API, the

- <code>IMPLEMENTATION_COLOR_READ_FORMAT</code> and

- <code>IMPLEMENTATION_COLOR_READ_TYPE</code> parameters are used to inform applications of an

- additional format and type combination that may be passed to <code>ReadPixels</code>, in

- addition to the required <ncode>RGBA</code>/<code>UNSIGNED_BYTE</code> pair. In WebGL 1.0,

- the supported format and type combinations to <code>ReadPixels</code> are documented in the

- <a href="#readpixels">Reading back pixels</a> section. The <code>IMPLEMENTATION_COLOR_READ_FORMAT</code>

- and <code>IMPLEMENTATION_COLOR_READ_TYPE</code> enumerants have been removed.

-</p>

- <h3><a name="COMPRESSED_TEXTURE_SUPPORT">Compressed Texture Support</a></h3>

-<p>

- WebGL does not support any compressed texture formats. Therefore the <code>CompressedTexImage2D</code>

- and <code>CompressedTexSubImage2D</code> functions are not included in this specification.

- Likewise the <code>COMPRESSED_TEXTURE_FORMATS</code> and <code>NUM_COMPRESSED_TEXTURE_FORMATS</code>

- parameters to <code>getParameter</code> will return the value null or zero.

-</p>

- <h3><a name="MAX_GLSL_IDENTIFIER_NAME">Maximum GLSL Identifier Name Limit</a></h3>

-<p>

- The GLSL ES spec <a href="#refsGLES20GLSL">[GLES20GLSL]</a> does not define a limit to the length

- of identifier names. WebGL requires support of identifier names of at least 256 characters in length.

-</p>

-

- <h2>References</h2>

- <h3>Normative references</h3>

- <dl>

- <dt id="refsTYPEDARRAYS">[TYPEDARRAYS]</dt>

- <dd><cite><a href="TypedArray-spec.html">

- Typed Array Specification: Editor's Draft</a></cite>,

- V. Vukicevic, K. Russell, May 2010.

- </dd>

- <dt id="refsGLES20">[GLES20]</dt>

- <dd><cite><a href="http://www.khronos.org/registry/gles/specs/2.0/es_full_spec_2.0.25.pdf">

- OpenGL® ES Common Profile Specification Version 2.0.25</a></cite>,

- A. Munshi, J. Leech, November 2010.

- </dd>

- <dt id="refsGLES20GLSL">[GLES20GLSL]</dt>

- <dd><cite><a href="http://www.khronos.org/registry/gles/specs/2.0/GLSL_ES_Specification_1.0.17.pdf">

- The OpenGL® ES Shading Language Version 1.00</a></cite>,

- R. Simpson, May 2009.

- </dd>

- <dt id="refsREGISTRY">[REGISTRY]</dt>

- <dd><cite><a href="http://www.khronos.org/registry/webgl/doc/spec/extensions/">

- WebGL Extension Registry</a></cite>

- </dd>

- <dt id="refsRFC2119">[RFC2119]</dt>

- <dd><cite><a href="http://www.ietf.org/rfc/rfc2119.txt">

- Key words for use in RFCs to Indicate Requirement Levels</a></cite>,

- S. Bradner. IETF, March 1997.

- </dd>

- <dt id="refsWEBIDL">[WEBIDL]</dt>

- <dd><cite><a href="http://dev.w3.org/2006/webapi/WebIDL/">

- Web IDL: W3C Editor’s Draft</a></cite>,

- C. McCormack, September 2009.

- </dd>

- </dl>

- <h3>Other references</h3>

-

- <h2>Acknowledgments</h2>

- <p>This specification is produced by the Khronos WebGL Working Group.</p>

- <p>

- Special thanks to: Arun Ranganathan (Mozilla), Jon Leech, Kenneth Russell (Google),

- Kenneth Waters (Google), Mark Callow (HI), Mark Steele (Mozilla), Oliver Hunt (Apple),

- Tim Johansson (Opera), Vangelis Kokkevis (Google), Vladimir Vukicevic (Mozilla),

- Gregg Tavares (Google)

- </p>

- <p>

- Additional thanks to: Alan Hudson (Yumetech), Bill Licea Kane (AMD), Cedric Vivier (Zegami),

- Dan Gessel (Apple), David Ligon (Qualcomm), Greg Ross (Nvidia), Jacob Strom (Ericsson), Kari Pulli (Nokia),

- Leddie Stenvie (ST-Ericsson), Neil Trevett (Nvidia), Per Wennersten (Ericsson),

- Per-Erik Brodin (Ericsson), Shiki Okasaka (Google), Tom Olson (ARM), Zhengrong Yao (Ericsson),

- and the members of the Khronos WebGL Working Group.

-</p>

-</body>

-</html>