shadows / scaning of the frame buffer

i’m working on real time shadows project,using the shadow volume algorithm.
I render shadow for cube object, but it has 2 shadow’s areas- black and darker black-
how can i scan (or manipulate) the frame buffer or the accumulate buffer in order to change the 2 areas to one black colour?


You shouldn’t have to do that, you’re propably doing something else wrong. Where exactly do these different colors occur? Remember the correct way to setup the lights:

First render ambient, then render shadow volumes, color and depth writes disabled, and then render the scene with the light and stencil testing, without any abmient at all. That way the shadows should go right, no need for post-processing.