[Gzz] GL bugs

[Benja Fallenstein]

Hi,

I've noted two bugs in the GL code while running the GL client (try 
'make rungl'):

1) The clipping of text vobs is interpolated wrongly: When not 
interpolating, everything is fine; when the interpolation starts, 
everything is visible; during the interpolation, the visible area 
shrinks until in the end the clipping is correct again (i.e., the 
clipped area is interpolated from being around the whole text-- 
rendering everything to be visible-- to being around the padded rect 
inside the cell, which is the correct clipping area)

2) The depth buffer stuff doesn't seem to be working; the depth ordering 
of overlapping cells is wrong in about 50% of the cases (i.e., seems 
unrelated to the actual depth...). To try, you can create the following 
structure:


A  E--D
|     |
B-----C

where A,B,C,D,E are cells; A and E will overlap.


The first issue (interpolation) is extremely nagging (it's the most 
glaring problem in the client right now).

- Benja