Surfaceless OutputSurface implementation.

content/browser/compositor/buffer_queue.h

+// 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.
+
+#ifndef CONTENT_BROWSER_COMPOSITOR_BUFFERED_OUTPUT_SURFACE_H_
+#define CONTENT_BROWSER_COMPOSITOR_BUFFERED_OUTPUT_SURFACE_H_
+
+#include <queue>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "content/common/content_export.h"
+#include "ui/gfx/size.h"
+
+namespace cc {
+class ContextProvider;
+}
+
+namespace content {
+
+// Provides a surface that manages its own uffers, backed by
+// CreateImageCHROMIUM. Double/triple buffering is implemented
+// internally. Doublebuffering occurs if PageFlipComplete is called before
+// the next BindFramebuffer call, otherwise it creates extra buffers.
+class CONTENT_EXPORT BufferQueue {
+ public:
+  BufferQueue(scoped_refptr<cc::ContextProvider> context_provider,
+              unsigned int internalformat);
+  ~BufferQueue();
+
+  bool Initialize();
+
+  void BindFramebuffer();
+  void SwapBuffers();
+  void PageFlipComplete();
+  void Reshape(const gfx::Size& size, float scale_factor);
+
+  unsigned int current_texture_id() { return current_surface_.texture; }
+
+ private:
+  friend class BufferQueueTest;
+  struct AllocatedSurface {
+    AllocatedSurface() : texture(0), image(0) {}
+    AllocatedSurface(unsigned int texture, unsigned int image)
+        : texture(texture), image(image) {}
+    unsigned int texture;
+    unsigned int image;
+  };
+
+  void FreeAllSurfaces();
+
+  void FreeSurface(AllocatedSurface* surface);
+
+  // Return a surface, available to be drawn into.
+  AllocatedSurface GetNextSurface();
+
+  gfx::Size size_;
+  scoped_refptr<cc::ContextProvider> context_provider_;
+  unsigned int fbo_;
+  size_t allocated_count_;
+  unsigned int internalformat_;
+  AllocatedSurface current_surface_;  // This surface is currently bound.
+  std::vector<AllocatedSurface> available_surfaces_;  // These are free for use.
+  std::queue<AllocatedSurface> in_flight_surfaces_;
+
+  DISALLOW_COPY_AND_ASSIGN(BufferQueue);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_COMPOSITOR_BUFFERED_OUTPUT_SURFACE_H_