Shadows
Shadows occur where objects are hidden from a light source
- omit any intensity contribution from hidden light sources
Working out what it hidden is simply a visibility problem
- can the light source see the object?
- use the z-buffer shadow algorithm:
- run the algorithm from the light source’s viewpoint
- save the z-buffer as the shadow buffer
- run the real z-buffer algorithm, transforming each point into the light source’s coordinates and comparing the z value against the shadow buffer