5.0 Summary

To cull shadow casters that do not affect the visible scene, we have introduced a shadow caster volume. Only objects that intersect both the shadow caster volume and the light source's bounding volume can cast a visible shadow.

For rendering shadow receiving semi-transparent objects, we can calculate a smaller shadow caster volume that only intersects objects that can cast a shadow onto the semi-transparent object, not the entire visible scene.

Once the shadow casters have been determined by using a shadow caster volume, scissor tests and depth tests can be used to reduce the amount of work done per shadow caster [LENG02b] [LENG05] .

Listing 1 is the implementation of the shadow caster volume calculation for a point light source. Listing 2 is a Polyhedron class that includes the calculations for polyhedron vertices and edges, and listing 3 is the LUP decomposition implementation.

References

Listings