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;
+  AdjustBufferAllocations();
+}
+
+void TextureImageTransportSurface::SetFrontbufferAllocation(bool allocation) {
+  if (frontbuffer_suggested_allocation_ == allocation)
+    return;
+  frontbuffer_suggested_allocation_ = allocation;
+  AdjustBufferAllocations();

[jonathan.backer, 2012/05/09 18:13:01]

Why are we doing this when AdjustBufferAllocations ignores it?

[mmocny, 2012/05/09 18:59:15]

Just for consistency.  I can remove it from this patch and add it once it does
something.

On 2012/05/09 18:13:01, jonathan.backer wrote:

[jonathan.backer, 2012/05/10 21:37:48]

I'm concerned that order of allocating buffers matters. For example, when a tab
is made visible, we may allocate a front and back buffer when previously we had
none. If we allocate the back and then the front, we will call CreateBackTexture
twice in AdjustBufferAllocations.

+}
+
+void TextureImageTransportSurface::AdjustBufferAllocations() {
   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::GetShareHandle() {
   return GetHandle();
 }
 
 void* TextureImageTransportSurface::GetDisplay() {
   return parent_stub_ ? parent_stub_->surface()->GetDisplay() : NULL;
 }
 
@@ skipping 250 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;
 }