Shadows moving with camera.

Question

I'm using MJP's Cascade Shadow Map code and I'm having major issues with the shadows moving with the camera. Here a video to demonstrate what's going on. Also, is there a way to fix the dueling frustum issue? It's annoying seeing them pop in and out of corners of the screen.

Video of the shadows

c# and shader code

Answer 1

It looks to me like your shadow render is lagging one frame behind the geometry render (or vice versa). I've had this in my own projects before now. Check your update and render order: you may be doing something like:

a) Update world/camera state
b) Draw Geometry
c) Draw shadows
d) Calc shadows with current (i.e. OLD) geom state

Answer 2

I'm not familiar with cascade shadow mapping (yet) but that sort of thing seems to happen in simple shadow mapping too, when using wrong parameters in the calculation of the shadow projections.

This should help (with near/far planes too): http://msdn.microsoft.com/en-us/library/windows/desktop/ee416324(v=vs.85).aspx

In your video the shadow edge seems to move bit more than just a 'shimmering' but it could be the result of a really far light source.