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()) {
   {
     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);
@@ skipping 34 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;
+  }
+
   buffer_manager_.reset(new BufferManager(
       memory_tracker_, feature_info_.get()));
-  framebuffer_manager_.reset(new FramebufferManager());
+  framebuffer_manager_.reset(new FramebufferManager(max_draw_buffers_));
   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 82 matching lines @@
     return false;
   }
 
   if (!texture_manager_->Initialize()) {
     LOG(ERROR) << "Context::Group::Initialize failed because texture manager "
                << "failed to initialize.";
     return false;
   }
 
   decoders_.push_back(base::AsWeakPtr<GLES2Decoder>(decoder));
+
+  DCHECK_GT(max_draw_buffers_, 0u);
+  draw_buffers_.reset(new GLenum[max_draw_buffers_]);
+  draw_buffers_[0] = GL_BACK;
+  for (uint32 i = 1; i < max_draw_buffers_; ++i)
+    draw_buffers_[i] = GL_NONE;
+
   return true;
 }
 
 namespace {
 
 bool IsNull(const base::WeakPtr<gles2::GLES2Decoder>& decoder) {
   return !decoder;
 }
 
 }  // namespace anonymous
@@ skipping 105 matching lines @@
 
 bool ContextGroup::QueryGLFeatureU(
     GLenum pname, GLint min_required, uint32* v) {
   uint32 value = 0;
   GetIntegerv(pname, &value);
   bool result = CheckGLFeatureU(min_required, &value);
   *v = value;
   return result;
 }
 
+GLenum ContextGroup::GetDrawBuffer(GLenum draw_buffer) const {
+  GLsizei index = static_cast<GLsizei>(
+      draw_buffer - GL_DRAW_BUFFER0_ARB);
+  DCHECK(index >= 0 && index < static_cast<GLsizei>(max_draw_buffers_));
+  return draw_buffers_[index];
+}
+
+void ContextGroup::SetDrawBuffers(GLsizei n, const GLenum* bufs) {
+  DCHECK(n <= static_cast<GLsizei>(max_draw_buffers_));
+  for (GLsizei i = 0; i < n; ++i)
+    draw_buffers_[i] = bufs[i];
+}
+
 }  // namespace gles2
 }  // namespace gpu