(I’ve asked this question some time ago on gamedev but haven’t got any answer that helped me so I’m posting this question here - hope you don’t mind)
Chapter 14 of GPUGems describes (at least a bit) a variation of PSM that uses a cube map to reduce aliasing. They show how to compute the texture coordinates for cube map access, but they don’t tell (clear enough) how to setup the view matrix for each cube map face in the post perspective space. Since the viewer for a directional light is on the infinity plane (and that means outside the unit cube) the usual 90 degree fov for cube map shadows doesn’t work. Can anyone help me with the view matrix setup for the light?
If anyone has already implemented PSM cube shadow maps: How much is aliasing reduced (especially in the real bad cases of standard PSM)? Is it worth the effort?