I've implemented an omni-directional shadow map and I've noticed a rather unwanted behaviour on the shadows. It seems like when the angle between the occluded points and the light source is really steap, then the egde of the shadow starts to wobble. It's almost looks like it's pulsating.
Could it have something to do with when the light source moves further away from the occluded polygons, the pixels next to each other are further away from each other than the corresponding texels on the shadow map face that I sample from which result in some sort of magnification side-effect when performing aliasing? This is just a really wild guess!
Is anyone familiar with this type of behaviour and/or have any solution to it?