Flag and adapter class for software compositing.

content/renderer/gpu/compositor_software_output_device_gl_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_software_output_device_gl_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;
+
+//------------------------------------------------------------------------------
+
+CompositorSoftwareOutputDeviceGLAdapter::
+    CompositorSoftwareOutputDeviceGLAdapter(WebGraphicsContext3D* context3D)
+    : initialized_(false),
+      program_(0),
+      vertex_shader_(0),
+      fragment_shader_(0),
+      vertex_buffer_(0),
+      framebuffer_texture_id_(0),
+      context3d_(context3D),
+      locked_for_write_(false) {
+}
+
+CompositorSoftwareOutputDeviceGLAdapter::
+    ~CompositorSoftwareOutputDeviceGLAdapter() {
+  Destroy();
+}
+
+WebImage* CompositorSoftwareOutputDeviceGLAdapter::lock(bool forWrite) {
+  locked_for_write_ = forWrite;
+  image_ = device_->accessBitmap(forWrite);
+  return &image_;
+}
+
+void CompositorSoftwareOutputDeviceGLAdapter::unlock() {
+  if (locked_for_write_)
+    Draw(device_->accessBitmap(false).pixelRef()->pixels());
+  image_.reset();
+}
+
+void CompositorSoftwareOutputDeviceGLAdapter::didChangeViewportSize(
+    WebSize size) {
+  if (!initialized_)
+    Initialize();
+
+  if (framebuffer_texture_size_ != gfx::Size(size))
+    Resize(size);
+}
+
+void CompositorSoftwareOutputDeviceGLAdapter::Initialize() {
+  // Vertex shader that flips the y axis.
+  static const char g_vertex_shader[] =
+    "attribute vec4 a_Position;"
+    "attribute vec2 a_texCoord;"
+    "varying vec2 v_texCoord;"
+    "void main() {"
+    "  gl_Position = a_Position;"
+    "  gl_Position.y = -gl_Position.y;"
+    "  v_texCoord = a_texCoord;"
+    "}";
+
+  // Pixel shader that swizzles RGBA -> BGRA.
+  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_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_);
+
+  vertex_buffer_ = context3d_->createBuffer();
+  context3d_->bindBuffer(GL_ARRAY_BUFFER, vertex_buffer_);
+  context3d_->bufferData(GL_ARRAY_BUFFER, 16 * sizeof(float), attribs,
+                         GL_STATIC_DRAW);
+  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");
+
+  context3d_->linkProgram(program_);
+  context3d_->useProgram(program_);
+
+  int texture_uniform = context3d_->getUniformLocation(program_, "s_texture");
+  context3d_->uniform1i(texture_uniform, 0);
+  context3d_->disable(GL_SCISSOR_TEST);
+  context3d_->clearColor(0, 0, 1, 1);
+
+  initialized_ = true;
+}
+
+void CompositorSoftwareOutputDeviceGLAdapter::Destroy() {
+  if (!initialized_)
+    return;
+
+  context3d_->makeContextCurrent();
+  context3d_->deleteShader(vertex_shader_);
+  context3d_->deleteShader(fragment_shader_);
+  context3d_->deleteProgram(program_);
+  context3d_->deleteBuffer(vertex_buffer_);
+  if (framebuffer_texture_id_)
+    context3d_->deleteTexture(framebuffer_texture_id_);
+}
+
+void CompositorSoftwareOutputDeviceGLAdapter::Resize(
+    const gfx::Size& viewport_size) {
+  framebuffer_texture_size_ = viewport_size;
+  device_.reset(new SkDevice(SkBitmap::kARGB_8888_Config,
+      viewport_size.width(), viewport_size.height(), true));
+
+  context3d_->makeContextCurrent();
+  context3d_->ensureFramebufferCHROMIUM();
+  framebuffer_texture_id_ = context3d_->createTexture();
+  context3d_->bindTexture(GL_TEXTURE_2D, framebuffer_texture_id_);
+  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, viewport_size.width(), viewport_size.height());
+  context3d_->reshape(viewport_size.width(), viewport_size.height());
+}
+
+void CompositorSoftwareOutputDeviceGLAdapter::Draw(void* pixels) {
+  if (!initialized_)
+    NOTREACHED();
+  if (!framebuffer_texture_id_)
+    NOTREACHED();
+
+  context3d_->makeContextCurrent();
+  context3d_->ensureFramebufferCHROMIUM();
+  context3d_->clear(GL_COLOR_BUFFER_BIT);
+
+  context3d_->texImage2D(GL_TEXTURE_2D, 0, GL_RGBA,
+      framebuffer_texture_size_.width(), framebuffer_texture_size_.height(),
+      0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+
+  context3d_->drawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+  context3d_->prepareTexture();
+}