Hallo,

I am working on a game where there is a post processing filter that runs on the final frame of the game. The strength of this filter is controlled by a seperate render target, so for every pixel I compute the filter value and lerp it with the original value based on the value found in the other rendering target.

This works fine, but xna (directx 9) does not support MSAA when using multiple rendering targets so I am looking for a way of getting around the need for having that second render target. Is there any way I can pack some of the data in the main render target or is there any texture formats with an 'extraData' attribute I can use? I was toying with the idea of using half the bits in the alpha for the original render target as the filter value, but that would mess up the alpha blending in the game.

Any ideas?