Original Post
Hello, I've been using stencil shadows for all dynamic shadowing for years now and I've not seriously looked into shadow maps. Now I'm moving to the great outdoors and I seriously need an image space approach. I've done a fair bit of research and I think I have a reasonable overview of all the more popular methods, but before I get into those I'd like to run some ideas of my own by someone with experience in shadow maps. One of the things I most dislike about shadow maps is the shimmering aliasing artifacts given by view-dependant methods. I am looking into directional lights, ie the sun, only (stencil shadows for other lights). My terrain is split into a square grid and each cell can be rendered independantly with it's own state set. Exploiting this, I would consider rendering a view-independant shadow map per cell. The advantages I see in this approach are: 1) View independant and hence aliasing artifacts don't move with camera transforms. 2) View independant and hence no need to re-render shadow maps for additional renderings in same time-slice (i.e. water reflections). 3) Per-cell updates means I can update distant shadow maps (very large portions of the scene) with considerably lower frequency. The only downside I see is the relatively poor distribution of samples in view space for a first person or similar view. This could result in poor resolution close up and minification artifacts further away. Also, I am presuming that I can trasform my shadow map projection so as to obtain an isotropic distribution of shadow map samples onto my square terrain cell. Not sure how yet but I presume this would be fairly easy? So, can someone with experience in shadow maps suggest how serious these issues might be and help me figure out if this approach could be worthwhile? Thanks