Add a pack buffer storage to BufferStorage11.

src/libGLESv2/renderer/d3d11/BufferStorage11.cpp

@@ -72,7 +72,7 @@ class BufferStorage11::TypedBufferStorage11
     virtual void *map(GLbitfield access) = 0;
     virtual void unmap() = 0;
 
-protected:
+  protected:
     TypedBufferStorage11(Renderer11 *renderer, BufferUsage usage);
 
     Renderer11 *mRenderer;
@@ -98,12 +98,32 @@ class BufferStorage11::NativeBuffer11 : public BufferStorage11::TypedBufferStora
     virtual void *map(GLbitfield access);
     virtual void unmap();
 
-private:
+  private:
     ID3D11Buffer *mNativeBuffer;
 
     static void fillBufferDesc(D3D11_BUFFER_DESC* bufferDesc, Renderer *renderer, BufferUsage usage, unsigned int bufferSize);
 };
 
+// Pack storage represents internal storage for pack buffers. We implement pack buffers
+// as CPU memory, tied to a staging texture, for asynchronous texture readback.
+class BufferStorage11::PackStorage11 : public BufferStorage11::TypedBufferStorage11
+{
+  public:
+    PackStorage11(Renderer11 *renderer);
+    ~PackStorage11();
+
+    virtual bool copyFromStorage(TypedBufferStorage11 *source, size_t sourceOffset,
+                                 size_t size, size_t destOffset);
+    virtual void resize(size_t size, bool preserveData);
+
+    virtual void *map(GLbitfield access);
+    virtual void unmap();
+
+  private:
+    ID3D11Texture2D *mStagingTexture;
+    unsigned char *mMemoryBuffer;
+};
+
 BufferStorage11::BufferStorage11(Renderer11 *renderer)
     : mRenderer(renderer),
       mIsMapped(false),
@@ -533,4 +553,40 @@ void BufferStorage11::NativeBuffer11::unmap()
     context->Unmap(mNativeBuffer, 0);
 }
 
+BufferStorage11::PackStorage11::PackStorage11(Renderer11 *renderer)
+    : TypedBufferStorage11(renderer, BUFFER_USAGE_PIXEL_PACK),
+      mStagingTexture(NULL),
+      mMemoryBuffer(NULL)
+{
+}
+
+BufferStorage11::PackStorage11::~PackStorage11()
+{
+    SafeRelease(mStagingTexture);
+    SafeDeleteArray(mMemoryBuffer);
+}
+
+bool BufferStorage11::PackStorage11::copyFromStorage(TypedBufferStorage11 *source, size_t sourceOffset,
+                                                     size_t size, size_t destOffset)
+{
+    UNIMPLEMENTED();
+    return false;
+}
+
+void BufferStorage11::PackStorage11::resize(size_t size, bool preserveData)
+{
+    UNIMPLEMENTED();
+}
+
+void *BufferStorage11::PackStorage11::map(GLbitfield access)
+{
+    UNIMPLEMENTED();
+    return NULL;
+}
+
+void BufferStorage11::PackStorage11::unmap()
+{
+    UNIMPLEMENTED();
+}
+
 }

src/libGLESv2/renderer/d3d11/BufferStorage11.h

@@ -22,6 +22,7 @@ enum BufferUsage
     BUFFER_USAGE_VERTEX_OR_TRANSFORM_FEEDBACK,
     BUFFER_USAGE_INDEX,
     BUFFER_USAGE_PIXEL_UNPACK,
+    BUFFER_USAGE_PIXEL_PACK,
     BUFFER_USAGE_UNIFORM,
 };
 
@@ -54,6 +55,7 @@ class BufferStorage11 : public BufferStorage
   private:
     class TypedBufferStorage11;
     class NativeBuffer11;
+    class PackStorage11;
 
     Renderer11 *mRenderer;
     bool mIsMapped;