In article <andrey.714155980@shum>, andrey@huji.ac.il (Andrey) writes:
|>
|> We have 4D/320VGX workstation. I've read in SG Technical Report,
|> section 5 (5.4.32 Sphere rendering) that the VISION graphics subsystem
|> supports high-speed rendering of high-quality spheres (without using
|> polygon primitives). Does somebody know how to use this possibility ?
|> The libsphere library provides only polygonal spheres, but for my
|> application it is too slow.
|> Any help will be greatly appreciated !
|>
|> Andrey Sigalov, Hebrew University, Jerusalem.
|> email: andrey@shum.huji.ac.il
|>
The description of the "2.5D" sphere rendering in the POWER Series Technical Report refers to a technique rather than an implemented GL feature. Since images can be BLTed into the frame buffer with Z values as well as RGBA values, a pre-defined image of a sphere can be stored as a template, with the pixels farther from the center having deeper Z values. The resultant BLT into the frame buffer at the desired location of the sphere would then properly occult any spheres farther back and would be properly occ
