Surfaceless OutputSurface implementation.

content/browser/compositor/buffered_output_surface.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 BufferedOutputSurface {

[piman, 2014/09/11 20:25:29]

nit: the name BufferedOutputSurface feels like it implements the
cc::OutputSurface interface, but it doesn't. Could we use a name that doesn't
suggest it? BufferQueue? SwapChain? Something like this?

[achaulk, 2014/09/15 16:31:42]

Done.

+ public:
+  BufferedOutputSurface(scoped_refptr<cc::ContextProvider> context_provider,
+                        unsigned int internalformat);
+  ~BufferedOutputSurface();
+
+  void Initialize();
+
+  void BindFramebuffer();
+  void SwapBuffers();
+  void PageFlipComplete();
+  void Reshape(const gfx::Size& size, float scale_factor);
+
+  unsigned int current_tex_id() { return current_surface_.first; }

[piman, 2014/09/11 20:25:29]

nit: no abbreviation. current_texture_id() ?

[achaulk, 2014/09/12 19:51:08]

Done.

+
+ private:
+  friend class BufferedOutputSurfaceTest;
+  typedef std::pair<unsigned int, unsigned int> AllocatedSurface;

[piman, 2014/09/11 20:25:29]

nit: can you make this a struct? It helps readability a lot. "first" and
"second" are poor names at the call sites.

[achaulk, 2014/09/12 19:51:08]

Done.

+
+  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_, depth_rb_;
+  size_t allocated_count_;
+  unsigned int internalformat_;
+  AllocatedSurface current_surface_;  // This surface is currently bound.
+  AllocatedSurface
+      last_surface_;  // This surface has been sent to the hardware.

[piman, 2014/09/11 20:25:29]

nit: keep member identifier and type on the same line, move the comment on the
line before.

+  std::vector<AllocatedSurface> available_surfaces_;  // These are free for use.
+  std::queue<AllocatedSurface> in_flight_surfaces_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_COMPOSITOR_BUFFERED_OUTPUT_SURFACE_H_