Decoupling backbuffer allocation suggestion from frontbuffer allocation suggestion.

content/common/gpu/texture_image_transport_surface.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/common/gpu/texture_image_transport_surface.h"
 
 #include "content/common/gpu/gpu_channel.h"
 #include "content/common/gpu/gpu_channel_manager.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "gpu/command_buffer/service/context_group.h"
@@ skipping 47 matching lines @@
 TextureImageTransportSurface::Texture::~Texture() {
 }
 
 TextureImageTransportSurface::TextureImageTransportSurface(
     GpuChannelManager* manager,
     GpuCommandBufferStub* stub,
     const gfx::GLSurfaceHandle& handle)
       : fbo_id_(0),
         front_(0),
         stub_destroyed_(false),
+        backbuffer_suggested_allocation_(true),
+        frontbuffer_suggested_allocation_(true),
         parent_stub_(NULL) {
   GpuChannel* parent_channel = manager->LookupChannel(handle.parent_client_id);
   DCHECK(parent_channel);
   parent_stub_ = parent_channel->LookupCommandBuffer(handle.parent_context_id);
   DCHECK(parent_stub_);
   parent_stub_->AddDestructionObserver(this);
   TextureManager* texture_manager =
       parent_stub_->decoder()->GetContextGroup()->texture_manager();
   DCHECK(texture_manager);
 
@@ skipping 70 matching lines @@
 #endif
   }
 
   return true;
 }
 
 unsigned int TextureImageTransportSurface::GetBackingFrameBufferObject() {
   return fbo_id_;
 }
 
-void TextureImageTransportSurface::SetBufferAllocation(
-    BufferAllocationState state) {
+void TextureImageTransportSurface::SetBackbufferAllocation(bool allocation) {
+  if (backbuffer_suggested_allocation_ == allocation)
+     return;
+  backbuffer_suggested_allocation_ = allocation;
+
   if (!helper_->MakeCurrent())
     return;
-  switch (state) {
-    case BUFFER_ALLOCATION_FRONT_AND_BACK:
-      CreateBackTexture(textures_[back()].size);
-      break;
-    case BUFFER_ALLOCATION_FRONT_ONLY:
-    case BUFFER_ALLOCATION_NONE:
-      ReleaseBackTexture();
-      break;
-  };
+
+  if (backbuffer_suggested_allocation_)
+    CreateBackTexture(textures_[back()].size);
+  else
+    ReleaseBackTexture();
+}
+
+void TextureImageTransportSurface::SetFrontbufferAllocation(bool allocation) {
+  if (frontbuffer_suggested_allocation_ == allocation)
+    return;
+  frontbuffer_suggested_allocation_ = allocation;
 }
 
 void* TextureImageTransportSurface::GetShareHandle() {
   return GetHandle();
 }
 
 void* TextureImageTransportSurface::GetDisplay() {
   return parent_stub_ ? parent_stub_->surface()->GetDisplay() : NULL;
 }
 
@@ skipping 15 matching lines @@
     // resources we allocated in the stub's context.
     glDeleteFramebuffersEXT(1, &fbo_id_);
     CHECK_GL_ERROR();
     fbo_id_ = 0;
 
     stub_destroyed_ = true;
   }
 }
 
 bool TextureImageTransportSurface::SwapBuffers() {
+  DCHECK(backbuffer_suggested_allocation_);

[jonathan.backer, 2012/05/15 15:53:31]

Why not exit early if no frontbuffer (I realize it would NOOP because we aren't
dropping front buffers yet, but you've done this for EGL as well, even though we
aren't dropping those front buffers). If you do add it (your call), the comments
for the EGL path hold.

[mmocny, 2012/05/15 20:02:28]

Fair point, I prefer to add it here than remove it there.

On 2012/05/15 15:53:31, jonathan.backer wrote:

   if (!parent_stub_) {
     LOG(ERROR) << "SwapBuffers failed because no parent stub.";
     return false;
   }
 
   glFlush();
   front_ = back();
   previous_damage_rect_ = gfx::Rect(textures_[front_].size);
 
   DCHECK(textures_[front_].client_id != 0);
 
   GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params params;
   params.surface_handle = textures_[front_].client_id;
   helper_->SendAcceleratedSurfaceBuffersSwapped(params);
   helper_->SetScheduled(false);
   return true;
 }
 
 bool TextureImageTransportSurface::PostSubBuffer(
     int x, int y, int width, int height) {
+  DCHECK(backbuffer_suggested_allocation_);

[jonathan.backer, 2012/05/15 15:53:31]

Same as above.

   if (!parent_stub_) {
     LOG(ERROR) << "PostSubBuffer failed because no parent stub.";
     return false;
   }
 
   DCHECK(textures_[back()].info);
   int back_texture_service_id = textures_[back()].info->service_id();
 
   DCHECK(textures_[front_].info);
   int front_texture_service_id = textures_[front_].info->service_id();
@@ skipping 195 matching lines @@
     Texture& texture = textures_[i];
     texture.info = NULL;
     if (!texture.sent_to_client)
       continue;
     GpuHostMsg_AcceleratedSurfaceRelease_Params params;
     params.identifier = texture.client_id;
     helper_->SendAcceleratedSurfaceRelease(params);
   }
   parent_stub_ = NULL;
 }