Add a simple compositor for Sky

sky/compositor/resource_manager.cc

Index: sky/compositor/resource_manager.cc
diff --git a/sky/compositor/resource_manager.cc b/sky/compositor/resource_manager.cc
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+// Copyright 2014 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 "sky/compositor/resource_manager.h"
+
+#ifndef GL_GLEXT_PROTOTYPES
+#define GL_GLEXT_PROTOTYPES
+#endif
+
+#include "base/logging.h"
+#include "gpu/GLES2/gl2chromium.h"
+#include "gpu/GLES2/gl2extchromium.h"
+#include "mojo/converters/geometry/geometry_type_converters.h"
+#include "mojo/gpu/gl_context.h"
+#include "mojo/gpu/gl_texture.h"
+#include "mojo/public/c/gles2/gles2.h"
+#include "sky/compositor/layer.h"
+
+namespace sky {
+
+ResourceManager::ResourceManager(base::WeakPtr<mojo::GLContext> gl_context)
+    : gl_context_(gl_context), next_resource_id_(0) {
+}
+
+ResourceManager::~ResourceManager() {
+}
+
+scoped_ptr<mojo::GLTexture> ResourceManager::CreateTexture(
+    const gfx::Size& size) {
+  gl_context_->MakeCurrent();
+  return make_scoped_ptr(new mojo::GLTexture(
+      gl_context_, mojo::TypeConverter<mojo::Size, gfx::Size>::Convert(size)));
+}
+
+mojo::TransferableResourcePtr ResourceManager::CreateTransferableResource(
+    Layer* layer) {
+  scoped_ptr<mojo::GLTexture> texture = layer->GetTexture();
+  mojo::Size size = texture->size();
+
+  gl_context_->MakeCurrent();
+  glBindTexture(GL_TEXTURE_2D, texture->texture_id());
+  GLbyte mailbox[GL_MAILBOX_SIZE_CHROMIUM];
+  glGenMailboxCHROMIUM(mailbox);
+  glProduceTextureCHROMIUM(GL_TEXTURE_2D, mailbox);
+  GLuint sync_point = glInsertSyncPointCHROMIUM();
+
+  mojo::TransferableResourcePtr resource = mojo::TransferableResource::New();
+  resource->id = next_resource_id_++;
+  resource_to_texture_map_[resource->id] = texture.release();
+  resource->format = mojo::RESOURCE_FORMAT_RGBA_8888;
+  resource->filter = GL_LINEAR;
+  resource->size = size.Clone();
+  resource->is_repeated = false;
+  resource->is_software = false;
+
+  mojo::MailboxHolderPtr mailbox_holder = mojo::MailboxHolder::New();
+  mailbox_holder->mailbox = mojo::Mailbox::New();
+  for (int i = 0; i < GL_MAILBOX_SIZE_CHROMIUM; ++i)
+    mailbox_holder->mailbox->name.push_back(mailbox[i]);
+  mailbox_holder->texture_target = GL_TEXTURE_2D;
+  mailbox_holder->sync_point = sync_point;
+  resource->mailbox_holder = mailbox_holder.Pass();
+
+  return resource.Pass();
+}
+
+void ResourceManager::ReturnResources(
+    mojo::Array<mojo::ReturnedResourcePtr> resources) {
+  DCHECK(resources.size());
+
+  gl_context_->MakeCurrent();
+  for (size_t i = 0u; i < resources.size(); ++i) {
+    mojo::ReturnedResourcePtr resource = resources[i].Pass();
+    DCHECK_EQ(1, resource->count);
+    glWaitSyncPointCHROMIUM(resource->sync_point);
+    mojo::GLTexture* texture = resource_to_texture_map_[resource->id];
+    DCHECK_NE(0u, texture->texture_id());
+    resource_to_texture_map_.erase(resource->id);
+    // TODO(abarth): Consider recycling the texture.
+    delete texture;
+  }
+}
+
+}  // namespace examples