Flag and adapter class for software compositing.

content/renderer/gpu/compositor_output_canvas_3d_to_2d_adapter.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/gpu/compositor_output_canvas_3d_to_2d_adapter.h"
+
+#include "base/logging.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/skia/include/core/SkPixelRef.h"
+#include "third_party/skia/include/core/SkDevice.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebGraphicsContext3D.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebSize.h"
+
+#include <GLES2/gl2.h>
+
+using WebKit::WebImage;
+using WebKit::WebGraphicsContext3D;
+using WebKit::WebSize;
+
+//------------------------------------------------------------------------------
+
+CompositorOutputCanvas3DTo2DAdapter::CompositorOutputCanvas3DTo2DAdapter(
+    WebGraphicsContext3D* context3D)
+    : initialized_(false)
+    , context3d_(context3D) {

[piman, 2012/08/28 03:31:57]

nit: style

CompositorOutputCanvas3DTo2DAdapter::CompositorOutputCanvas3DTo2DAdapter(
    WebGraphicsContext3D* context3D)
    : initialized_(false)
      context3d_(context3D) {

[aelias_OOO_until_Jul13, 2012/08/28 23:10:58]

Done.

+}
+
+CompositorOutputCanvas3DTo2DAdapter::~CompositorOutputCanvas3DTo2DAdapter() {
+}
+
+WebImage* CompositorOutputCanvas3DTo2DAdapter::lock() {
+  if (!initialized_)

[piman, 2012/08/28 03:31:57]

you could also make Initialize() explicit when the CompositorOutputSurface is
bound to client.

[aelias_OOO_until_Jul13, 2012/08/28 23:10:58]

I'd rather not introduce a new API.  But I moved the Initialize call to
viewportChanged()

[piman, 2012/08/28 23:26:59]

I was really thinking, CompositorOutputSurface can keep a pointer to the
concrete type, and call Initialize explicitly, so that you don't need to add it
to the webkit interface (which I agree doesn't belong).

[aelias_OOO_until_Jul13, 2012/08/28 23:53:11]

I'd also like CompositorOutputSurface to stay indifferent to concrete type in
case we have another implementation in the future.  I don't see the problem with
the lazy initialization.

+    initGLAdapter();
+
+  image_ = device_->accessBitmap(true);
+  return &image_;
+}
+
+void CompositorOutputCanvas3DTo2DAdapter::unlockAndOutputFrame() {
+  frameDrawGLAdapter(device_->accessBitmap(false).pixelRef()->pixels());
+  image_.reset();
+}
+
+void CompositorOutputCanvas3DTo2DAdapter::viewportChanged(const WebSize& size) {
+  if (framebufferTextureSize_ != gfx::Size(size))
+    textureGLAdapter(size);
+}
+
+void CompositorOutputCanvas3DTo2DAdapter::initGLAdapter() {
+  static const char g_vertex_shader[] =
+    "attribute vec4 a_Position;"
+    "attribute vec2 a_texCoord;"
+    "varying vec2 v_texCoord;"
+    "void main() {"
+    "  gl_Position = a_Position;"
+    "  v_texCoord = a_texCoord;"
+    "}";
+
+  // Minimal texture mapping pixel shader, swizzling appropriately.
+  static const char g_fragment_shader[] =
+    "precision mediump float;"
+    "varying vec2 v_texCoord;"
+    "uniform sampler2D s_texture;"
+    "void main() {"
+    "  gl_FragColor = texture2D(s_texture, v_texCoord).bgra;"
+    "}";
+
+  const GLfloat attribs[] = {
+    -1.0f, -1.0f,
+    1.0f, -1.0f,
+    -1.0f, 1.0f,
+    1.0f, 1.0f,
+    0.0f, 0.0f,
+    1.0f, 0.0f,
+    0.0f, 1.0f,
+    1.0f, 1.0f };
+
+  context3d_->makeContextCurrent();
+
+  vertex_buffer_ = context3d_->createBuffer();

[piman, 2012/08/28 03:31:57]

We will need to release all resources: VBOs, shaders (you can delete after
attaching to program), programs, textures.
All contexts in a renderer are shared, so you can't rely on the context
destruction to free the resources.

[aelias_OOO_until_Jul13, 2012/08/28 23:10:58]

I added some cleanup stuff in the destructor.  But when I close tabs, the
destructor is never called.  Not sure the best place to change to make sure the
WebCompositorOutputSurface is destroyed?

[piman, 2012/08/28 23:26:59]

Most of the time, if we only have one tab in the renderer, the renderer gets
killed when you close the tab, so we're fine.
The case happens when you have several tabs in the same renderer (e.g. if they
are linked because you middle-clicked or something). I hope we do call the
destructor in that case (otherwise we have another problem).

+  context3d_->bindBuffer(GL_ARRAY_BUFFER, vertex_buffer_);
+  context3d_->bufferData(GL_ARRAY_BUFFER, 16 * sizeof(float), attribs,
+                         GL_STATIC_DRAW);
+
+  vertex_shader_ = context3d_->createShader(GL_VERTEX_SHADER);
+  context3d_->shaderSource(vertex_shader_, g_vertex_shader);
+  context3d_->compileShader(vertex_shader_);
+
+  fragment_shader_ = context3d_->createShader(GL_FRAGMENT_SHADER);
+  context3d_->shaderSource(fragment_shader_, g_fragment_shader);
+  context3d_->compileShader(fragment_shader_);
+
+  program_ = context3d_->createProgram();
+  context3d_->attachShader(program_, vertex_shader_);
+  context3d_->attachShader(program_, fragment_shader_);
+  context3d_->linkProgram(program_);
+
+  texture_uniform_ = context3d_->getUniformLocation(program_, "s_texture");

[piman, 2012/08/28 03:31:57]

you can set all the program state at this point, so that you don't need to keep
the location in a field (just set the value to 0 as you do below).

+
+  initialized_ = true;
+}
+
+void CompositorOutputCanvas3DTo2DAdapter::textureGLAdapter(
+    const gfx::Size& viewportSize) {
+  framebufferTextureSize_ = viewportSize;
+  device_.reset(new SkDevice(SkBitmap::kARGB_8888_Config,
+      viewportSize.width(), viewportSize.height(), true));
+
+  context3d_->makeContextCurrent();
+  context3d_->ensureFramebufferCHROMIUM();
+  framebufferTextureId_ = context3d_->createTexture();
+  context3d_->bindTexture(GL_TEXTURE_2D, framebufferTextureId_);
+  context3d_->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  context3d_->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  context3d_->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  context3d_->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+  context3d_->viewport(0, 0, viewportSize.width(), viewportSize.height());
+  context3d_->reshape(viewportSize.width(), viewportSize.height());
+}
+
+void CompositorOutputCanvas3DTo2DAdapter::frameDrawGLAdapter(void* pixels) {
+  if (program_ == GL_ZERO)

[piman, 2012/08/28 03:31:57]

if (!program_)

[aelias_OOO_until_Jul13, 2012/08/28 23:10:58]

Done.

+    NOTREACHED();
+  if (framebufferTextureId_ == GL_ZERO)

[piman, 2012/08/28 03:31:57]

if (!framebuffer_texture_id_)

[aelias_OOO_until_Jul13, 2012/08/28 23:10:58]

Done.

+    NOTREACHED();
+
+  context3d_->makeContextCurrent();
+  context3d_->ensureFramebufferCHROMIUM();
+  context3d_->clearColor(0, 0, 1, 1);
+  context3d_->disable(GL_SCISSOR_TEST);

[piman, 2012/08/28 03:31:57]

move to Initialize()

[aelias_OOO_until_Jul13, 2012/08/28 23:10:58]

Moved it all to Initialize().

+  context3d_->clear(GL_COLOR_BUFFER_BIT);
+
+  context3d_->activeTexture(GL_TEXTURE0);

[piman, 2012/08/28 03:31:57]

move to Initialize() (actually, it's redundant, TEXTURE0 is the default)

+  context3d_->bindTexture(GL_TEXTURE_2D, framebufferTextureId_);

[piman, 2012/08/28 03:31:57]

redundant

+  context3d_->texImage2D(GL_TEXTURE_2D, 0, GL_RGBA,
+      framebufferTextureSize_.width(), framebufferTextureSize_.height(),
+      0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+
+  context3d_->useProgram(program_);

[piman, 2012/08/28 03:31:57]

move to Initialize()

+  context3d_->uniform1i(texture_uniform_, 0);

[piman, 2012/08/28 03:31:57]

move to Initialize()

+  context3d_->activeTexture(GL_TEXTURE0);

[piman, 2012/08/28 03:31:57]

redundant

+  context3d_->bindTexture(GL_TEXTURE_2D, framebufferTextureId_);

[piman, 2012/08/28 03:31:57]

redundant

+
+  context3d_->bindBuffer(GL_ARRAY_BUFFER, vertex_buffer_);
+  context3d_->enableVertexAttribArray(0);
+  context3d_->vertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
+  context3d_->bindAttribLocation(program_, 0, "a_Position");
+  context3d_->enableVertexAttribArray(1);
+  context3d_->vertexAttribPointer(
+      1, 2, GL_FLOAT, GL_FALSE, 0, 8 * sizeof(GLfloat));
+  context3d_->bindAttribLocation(program_, 1, "a_texCoord");

[piman, 2012/08/28 03:31:57]

Just move all the attrib binding to Initialize.
Note: bindAttribLocation has no effect until linkProgram, so this is wrong
anyway (and may just be lucky with the default bindings)

+
+  context3d_->drawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+  context3d_->prepareTexture();
+}