What is the "light volume optimization"? Can you describe in more detail?
I don't understand the problem...normally you (1) decide on the projection - based on light and camera positions etc. - then (2) render the shadow map with that projection and (3) apply it to the camera view with the same projection. So I'm not sure what you are trying to do with "extracting" the projection?
I'll get straight to the point, sorry for my poor explanation. Actually I've
implemented hardware shadow map with PCF. They workj perfect in my small
demo test bed.
Then I tried in integrating them in my deferred renderer.
I use one render target format R32F for depth and a depth/stencil surface. I
set both of them before to render from the light point of view. One thing
that I've noiced is that the depth buffer it doesn't get updated at all while
rendering... it's just stays black !!! this is going to happen with the main depth buferr as well as my depthstencil surface that I use during shadow map generation, I see just black depth buffer !!!