Image GLCanvas::GetImage() {
	Size sz = GetSize();
	ImageBuffer ib(sz);

	glGetError();
	glReadPixels(0, 0, sz.cx, sz.cy, GL_BGRA_EXT, GL_UNSIGNED_BYTE, static_cast<GLvoid *>(~ib));
	if (GL_NO_ERROR != glGetError())
		return Null;
	
	Buffer<RGBA> temp(sz.cx);
	for(int i = 0; i < sz.cy/2; i++){
		memcpy(temp,ib[i], sz.cx*sizeof(RGBA));
		memcpy(ib[i], ib[sz.cy-1-i], sz.cx*sizeof(RGBA));
		memcpy(ib[sz.cy-1-i], temp, sz.cx*sizeof(RGBA));
	}
	
	for (int y = 0; y < sz.cy; y++)
		for (int x = 0; x < sz.cx; x++) 
			ib[y][x].a = 255;

	return ib;
}