Surfaceless OutputSurface implementation.

content/browser/compositor/buffer_queue.cc

+// 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 "content/browser/compositor/buffer_queue.h"
+
+#include "content/common/gpu/client/context_provider_command_buffer.h"
+#include "gpu/GLES2/gl2extchromium.h"
+#include "gpu/command_buffer/client/gles2_interface.h"
+
+namespace content {
+
+BufferQueue::BufferQueue(scoped_refptr<cc::ContextProvider> context_provider,
+                         unsigned int internalformat)
+    : context_provider_(context_provider),
+      fbo_(0),
+      allocated_count_(0),
+      internalformat_(internalformat) {
+}
+
+BufferQueue::~BufferQueue() {
+  FreeAllSurfaces();
+
+  gpu::gles2::GLES2Interface* gl = context_provider_->ContextGL();
+  if (fbo_)
+    gl->DeleteFramebuffers(1, &fbo_);
+}
+
+bool BufferQueue::Initialize() {
+  gpu::gles2::GLES2Interface* gl = context_provider_->ContextGL();
+  gl->GenFramebuffers(1, &fbo_);
+  return fbo_ != 0;
+}
+
+void BufferQueue::BindFramebuffer() {
+  gpu::gles2::GLES2Interface* gl = context_provider_->ContextGL();
+  gl->BindFramebuffer(GL_FRAMEBUFFER, fbo_);
+
+  if (!current_surface_.texture) {
+    current_surface_ = GetNextSurface();
+    gl->FramebufferTexture2D(GL_FRAMEBUFFER,
+                             GL_COLOR_ATTACHMENT0,
+                             GL_TEXTURE_2D,
+                             current_surface_.texture,
+                             0);
+  }
+}
+
+void BufferQueue::SwapBuffers() {
+  in_flight_surfaces_.push(current_surface_);
+  current_surface_.texture = 0;
+  current_surface_.image = 0;
+}
+
+void BufferQueue::Reshape(const gfx::Size& size, float scale_factor) {
+  DCHECK(!current_surface_.texture);
+  if (size == size_)
+    return;
+  size_ = size;
+
+  // TODO: add stencil buffer when needed.
+  gpu::gles2::GLES2Interface* gl = context_provider_->ContextGL();
+  gl->BindFramebuffer(GL_FRAMEBUFFER, fbo_);
+  gl->FramebufferTexture2D(
+      GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);
+
+  FreeAllSurfaces();
+}
+
+void BufferQueue::PageFlipComplete() {
+  if (in_flight_surfaces_.size() > 1) {
+    available_surfaces_.push_back(in_flight_surfaces_.front());
+    in_flight_surfaces_.pop();
+  }
+}
+
+void BufferQueue::FreeAllSurfaces() {
+  FreeSurface(&current_surface_);
+  while (!in_flight_surfaces_.empty()) {
+    FreeSurface(&in_flight_surfaces_.front());
+    in_flight_surfaces_.pop();
+  }
+  for (size_t i = 0; i < available_surfaces_.size(); i++)
+    FreeSurface(&available_surfaces_[i]);
+  available_surfaces_.clear();
+}
+
+void BufferQueue::FreeSurface(AllocatedSurface* surface) {
+  if (surface->texture) {
+    gpu::gles2::GLES2Interface* gl = context_provider_->ContextGL();
+    gl->BindTexture(GL_TEXTURE_2D, surface->texture);
+    gl->ReleaseTexImage2DCHROMIUM(GL_TEXTURE_2D, surface->image);
+    gl->DeleteTextures(1, &surface->texture);
+    gl->DestroyImageCHROMIUM(surface->image);
+    surface->image = 0;
+    surface->texture = 0;
+    allocated_count_--;
+  }
+}
+
+BufferQueue::AllocatedSurface BufferQueue::GetNextSurface() {
+  if (!available_surfaces_.empty()) {
+    AllocatedSurface id = available_surfaces_.back();
+    available_surfaces_.pop_back();
+    return id;
+  }
+
+  unsigned int texture = 0;
+  gpu::gles2::GLES2Interface* gl = context_provider_->ContextGL();
+  gl->GenTextures(1, &texture);
+  if (!texture)
+    return AllocatedSurface();
+
+  // We don't want to allow anything more than triple buffering.
+  DCHECK_LT(allocated_count_, 4U);
+
+  unsigned int id = context_provider_->ContextGL()->CreateImageCHROMIUM(
+      size_.width(),
+      size_.height(),
+      internalformat_,
+      GL_IMAGE_SCANOUT_CHROMIUM);
+  allocated_count_++;
+  gl->BindTexture(GL_TEXTURE_2D, texture);
+  gl->BindTexImage2DCHROMIUM(GL_TEXTURE_2D, id);
+  return AllocatedSurface(texture, id);
+}
+
+}  // namespace content