There seems to be depth buffer issues with transparent objects with the Unichrome. Although the objects are not visible against the background since they are transparent, they seem to somehow obscure other objects. Perhaps objects that get drawn later. To reproduce: Launch tucracer. At the beginning of the first lap, Tux will suddenly disappear, and then reappear again. Also at the start of the second level, The starting banner seems to be obscured by a transparent object.
Sounds like the alpha test is broken. I vaguely remember fixing a related problem in the Savage driver once. On the Savage there is a bit that says "write Z after alpha test". If you don't set that bit then fragments that fail the alpha test still write a Z value so that they "obscure" stuff that is drawn later.
Mass version move, cvs -> git
The Unichrome driver longer exists in Mesa.
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