Added a copyBufferSubData method to Buffer.

src/libGLESv2/Buffer.cpp

@@ -65,6 +65,18 @@ void Buffer::bufferSubData(const void *data, GLsizeiptr size, GLintptr offset)
     mUnmodifiedDataUse = 0;
 }
 
+void Buffer::copyBufferSubData(Buffer* source, GLintptr sourceOffset, GLintptr destOffset, GLsizeiptr size)
+{
+    mBufferStorage->copyData(source->mBufferStorage, size, sourceOffset, destOffset);
+
+    if ((mStaticVertexBuffer && mStaticVertexBuffer->getBufferSize() != 0) || (mStaticIndexBuffer && mStaticIndexBuffer->getBufferSize() != 0))
+    {
+        invalidateStaticData();
+    }
+
+    mUnmodifiedDataUse = 0;
+}
+
 rx::BufferStorage *Buffer::getStorage() const
 {
     return mBufferStorage;

src/libGLESv2/Buffer.h

@@ -34,6 +34,7 @@ class Buffer : public RefCountObject
 
     void bufferData(const void *data, GLsizeiptr size, GLenum usage);
     void bufferSubData(const void *data, GLsizeiptr size, GLintptr offset);
+    void copyBufferSubData(Buffer* source, GLintptr sourceOffset, GLintptr destOffset, GLsizeiptr size);
 
     GLenum usage() const;