The distance to occluder buffer is a screen space "inverse shadow map" if you will. For each screen space pixel it stores the distance from the surface under that pixel to closest occluder, should one exist.
We are in fact casting a real ray from each non-trivially shadowed pixel towards the light source. We're using the PowerVR Wizard GPU's hardware ray tracing unit to accelerate process. Pixels who's surface is back-facing WRT the light (i.e. N dot L < 0) we know are shadowed so there's no need to cast any rays.
We are in fact casting a real ray from each non-trivially shadowed pixel towards the light source. We're using the PowerVR Wizard GPU's hardware ray tracing unit to accelerate process. Pixels who's surface is back-facing WRT the light (i.e. N dot L < 0) we know are shadowed so there's no need to cast any rays.