ui/gfx/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_GFX_GPU_MEMORY_BUFFER_H_
   6 #define UI_GFX_GPU_MEMORY_BUFFER_H_
   7
   8 #include "base/memory/shared_memory.h"
   9 #include "build/build_config.h"
  10 #include "ui/gfx/gfx_export.h"
  11
  12 #if defined(OS_ANDROID)
  13 #include <third_party/khronos/EGL/egl.h>
  14 #endif
  15
  16 namespace gfx {
  17
  18 enum GpuMemoryBufferType {
  19   EMPTY_BUFFER,
  20   SHARED_MEMORY_BUFFER,
  21   EGL_CLIENT_BUFFER
  22 };
  23
  24 struct GpuMemoryBufferHandle {
  25   GpuMemoryBufferHandle()
  26       : type(EMPTY_BUFFER),
  27         handle(base::SharedMemory::NULLHandle())
  28 #if defined(OS_ANDROID)
  29         , native_buffer(NULL)
  30 #endif
  31   {
  32   }
  33   bool is_null() const { return type == EMPTY_BUFFER; }
  34   GpuMemoryBufferType type;
  35   base::SharedMemoryHandle handle;
  36 #if defined(OS_ANDROID)
  37   EGLClientBuffer native_buffer;
  38 #endif
  39 };
  40
  41 // Interface for creating and accessing a zero-copy GPU memory buffer.
  42 // This design evolved from the generalization of GraphicBuffer API
  43 // of Android framework.
  44 //
  45 // THREADING CONSIDERATIONS:
  46 //
  47 // This interface is thread-safe. However, multiple threads mapping
  48 // a buffer for Write or ReadOrWrite simultaneously may result in undefined
  49 // behavior and is not allowed.
  50 class GFX_EXPORT GpuMemoryBuffer {
  51  public:
  52   enum AccessMode {
  53     READ_ONLY,
  54     WRITE_ONLY,
  55     READ_WRITE,
  56   };
  57
  58   GpuMemoryBuffer();
  59   virtual ~GpuMemoryBuffer();
  60
  61   // Maps the buffer so the client can write the bitmap data in |*vaddr|
  62   // subsequently. This call may block, for instance if the hardware needs
  63   // to finish rendering or if CPU caches need to be synchronized.
  64   virtual void Map(AccessMode mode, void** vaddr) = 0;
  65
  66   // Unmaps the buffer. Called after all changes to the buffer are
  67   // completed.
  68   virtual void Unmap() = 0;
  69
  70   // Returns true iff the buffer is mapped.
  71   virtual bool IsMapped() const = 0;
  72
  73   // Returns the stride in bytes for the buffer.
  74   virtual uint32 GetStride() const = 0;
  75
  76   // Returns a platform specific handle for this buffer.
  77   virtual GpuMemoryBufferHandle GetHandle() const = 0;
  78 };
  79
  80 }  // namespace gfx
  81
  82 #endif  // UI_GFX_GPU_MEMORY_BUFFER_H_