3dfx V1 paletted texture errors

[leilei-]

OA's paletted texture feature is designed for an Index w/ transparent color format, which the 3dfx Voodoo Graphics GL ICD does not support (but all the later Voodoos starting from Voodoo2 do). As a result, all the indexed alpha texels on paletted textures are not rendered transparent.

A solution would be to have them processed as 16-bit RGBA (with a paletted processing, how GLQuake and Quake2 did it) and upload them as that, though it would be trickier to detect the V1's palette support limits to determine this behavior.

[leilei-]

Sort of fixed.