ui/gl/gpu_memory_buffer.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_GL_GPU_MEMORY_BUFFER_H_
   6 #define UI_GL_GPU_MEMORY_BUFFER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback.h"
  10 #include "base/memory/scoped_ptr.h"
  11
  12 namespace gfx {
  13 class Size;
  14
  15 // Interface for creating and accessing a zero-copy GPU memory buffer.
  16 // This design evolved from the generalization of GraphicBuffer API
  17 // of Android framework.
  18 //
  19 // THREADING CONSIDERATIONS:
  20 //
  21 // This interface is thread-safe. However, multiple threads mapping
  22 // a buffer for Write or ReadOrWrite simultaneously may result in undefined
  23 // behavior and is not allowed.
  24 class GpuMemoryBuffer {
  25  public:
  26   typedef base::Callback<scoped_ptr<gfx::GpuMemoryBuffer>(gfx::Size)> Create;
  27   enum AccessMode {
  28     READ_ONLY,
  29     WRITE_ONLY,
  30     READ_OR_WRITE,
  31   };
  32
  33   // Frees a previously allocated buffer. Freeing a buffer that is still
  34   // mapped in any process is undefined behavior.
  35   virtual ~GpuMemoryBuffer() {}
  36
  37   // Maps the buffer so the client can write the bitmap data in |*vaddr|
  38   // subsequently. This call may block, for instance if the hardware needs
  39   // to finish rendering or if CPU caches need to be synchronized.
  40   virtual void Map(AccessMode mode, void** vaddr) = 0;
  41
  42   // Unmaps the buffer. Called after all changes to the buffer are
  43   // completed.
  44   virtual void Unmap() = 0;
  45
  46   // Returns the native pointer for the buffer.
  47   virtual void* GetNativeBuffer() = 0;
  48
  49   // Returns the stride in pixels for the buffer.
  50   virtual uint32 GetStride() = 0;
  51 };
  52
  53 }  // namespace gfx
  54
  55 #endif  // UI_GL_GPU_MEMORY_BUFFER_H_