private void Bind(RenderContext context, DeviceContextProxy deviceContext)
{
targets = deviceContext.GetRenderTargets(2);
deviceContext.ClearRenderTargetView(colorTarget, Color.Zero);
deviceContext.ClearRenderTargetView(alphaTarget, Color.White);
deviceContext.SetRenderTargets(context.RenderHost.DepthStencilBufferView,
new RenderTargetView[] { colorTarget, alphaTarget });
}