I remember that the OpenGL occlusion query code was especially glitchy-- it had a bad tendency to make things become invisible for no apparent reason! Context: I wrote Optimine (early graphics optimization mod) and MCRegion (optimized file format that became the Region/Anvil formats).
I'm not sure why they're doing a full flood-fill-- why compute connectivity instead of visibility? Knowing the answers to "entering through face A, can a ray exit through face B?" should solve the same problem and also be easier to compute.
This sounds very similar to http://en.wikipedia.org/wiki/Potentially_visible_set
I'm not sure why they're doing a full flood-fill-- why compute connectivity instead of visibility? Knowing the answers to "entering through face A, can a ray exit through face B?" should solve the same problem and also be easier to compute.