I saw this image and I currently have CSM implemented in my SlimDx project. However, when the camera roates, you notices the shadows move slightly. I'm not talking about the jagged edges that swim. I was hoping someone could explain more of the process about using bounding spheres for stabling CSM.
To remove the edge shimmering you can follow this article scroll down to the section "Moving the Light in Texel-Sized Increments" and also this topic (read the second MJP post and you should be able to fix it!).
The image is from ShaderX6, if you're interested. The basic idea is that for each cascade, you partition the viewing frustum using a depth range and then build the 8 corners around the slice of the frustum representing that particular partition. Normally you build a light-space AABB around those corners to get a tight fit, but with stable CSM you use a bounding sphere instead (which you can actually do in world space instead of light space, since it doesn't matter for a sphere). Then you also do a little math to round off the translation of each partition, so that they only move in texel-sized increments.