Implement EXT_draw_buffers WebGL extention support in command buffer.

gpu/command_buffer/service/context_group.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 "gpu/command_buffer/service/context_group.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 28 matching lines @@
       enforce_gl_minimums_(CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnforceGLMinimums)),
       bind_generates_resource_(bind_generates_resource),
       max_vertex_attribs_(0u),
       max_texture_units_(0u),
       max_texture_image_units_(0u),
       max_vertex_texture_image_units_(0u),
       max_fragment_uniform_vectors_(0u),
       max_varying_vectors_(0u),
       max_vertex_uniform_vectors_(0u),
+      max_color_attachments_(1u),
+      max_draw_buffers_(1u),
       program_cache_(NULL),
-      feature_info_(new FeatureInfo()) {
+      feature_info_(new FeatureInfo()),
+      draw_buffer_(GL_BACK) {
   {
     TransferBufferManager* manager = new TransferBufferManager();
     transfer_buffer_manager_.reset(manager);
     manager->Initialize();
   }
 
   id_namespaces_[id_namespaces::kBuffers].reset(new IdAllocator);
   id_namespaces_[id_namespaces::kFramebuffers].reset(new IdAllocator);
   id_namespaces_[id_namespaces::kProgramsAndShaders].reset(
       new NonReusedIdAllocator);
@@ skipping 32 matching lines @@
       &max_renderbuffer_size)) {
     LOG(ERROR) << "ContextGroup::Initialize failed because maximum "
                << "renderbuffer size too small.";
     return false;
   }
   GLint max_samples = 0;
   if (feature_info_->feature_flags().chromium_framebuffer_multisample) {
     glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
   }
 
+  if (feature_info_->feature_flags().ext_draw_buffers) {
+    GetIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &max_color_attachments_);
+    if (max_color_attachments_ < 1)
+      max_color_attachments_ = 1;
+    GetIntegerv(GL_MAX_DRAW_BUFFERS_ARB, &max_draw_buffers_);
+    if (max_draw_buffers_ < 1)
+      max_draw_buffers_ = 1;
+    draw_buffer_ = GL_BACK;
+  }
+
   buffer_manager_.reset(new BufferManager(
       memory_tracker_, feature_info_.get()));
-  framebuffer_manager_.reset(new FramebufferManager());
+  framebuffer_manager_.reset(
+      new FramebufferManager(max_draw_buffers_, max_color_attachments_));
   renderbuffer_manager_.reset(new RenderbufferManager(memory_tracker_,
                                                       max_renderbuffer_size,
                                                       max_samples));
   shader_manager_.reset(new ShaderManager());
   program_manager_.reset(new ProgramManager(program_cache_));
 
   // Lookup GL things we need to know.
   const GLint kGLES2RequiredMinimumVertexAttribs = 8u;
   if (!QueryGLFeatureU(
       GL_MAX_VERTEX_ATTRIBS, kGLES2RequiredMinimumVertexAttribs,
@@ skipping 209 matching lines @@
     GLenum pname, GLint min_required, uint32* v) {
   uint32 value = 0;
   GetIntegerv(pname, &value);
   bool result = CheckGLFeatureU(min_required, &value);
   *v = value;
   return result;
 }
 
 }  // namespace gles2
 }  // namespace gpu