I am generating graphics which has premultiplied alpha so a pure red rendered with 10% opasity would result in 10% red.
Now the problem is that the mixer receiving this signal does some alphamultiplication again leaving the red at 10% color*10% alpha = 1% color. For this reason I need to predevide my color with alpha, so my rendered 10% color is divided with 10% resulting in 100% color and 10% alpha which the mixer can then multiply my 100% red with 10% alpha resulting in 10% color which is what I want.
Ok, the question is then if opengl might have support for something like this? Can it perform a component wise operation for each pixel or will I have to implement this in a shader myself? I assume the latter, but before implementing it I would check here :-)