OnRenderImage is called after all rendering is complete to render image.
It allows you to modify final image by processing it with shader based filters. The incoming image is
source render texture. The result should end up in
destination render texture. You must always issue a Graphics.Blit or render a fullscreen quad if you override this method.
When there are multiple image filters attached to the camera, they process image sequentially, by passing first filter's destination as the source to the next filter.
This message is sent to all scripts attached to the camera.
Android: Use the Android Player Settings to make changes. Select the Use 32-bit Display Buffer option to use a post-processing effect with the alpha channel, or experience Banding Effects. The alpha channel is not available in a 16-bit Render Texture.
See Also: Writing Post-Processing Effects.