gl_FragDepth problem

I’ve run into problems when trying to set the depth of a fragment using gl_FragDepth.
My aim is to offset the object to the front a bit while using a depthtest, as to achieve a ‘band’ similar as one would use polygon_offset.

However, gl_FragDepth behaves very strangely.
It renders ok when we would write:

gl_FragDepth = gl_FragCoord.z;

and it EVEN COMPILES AND RUNS when I say:

gl_FragDepth = gl_FragCoord.z + 1; // SHOULD GENERATE TYPE CAST ERROR

When I use:

gl_FragDepth = a;

with a between (0.0, 1.0) :slight_smile: gives always the same erroneous depthmap.

I got this strange behaviour under linux (driver 61.11) using a GeForce FX 5200.


I’m having the same problem on a gf6800 GT / winXP combination.

It appears that setting gl_FragDepth has no effect at all.


I’m on version 61.77 (win2k), same problem. I experienced it on GeForce FX as well as on 6800. Maybe it only happens in Belgium, though? :slight_smile:

I’ll contact NVidia and see if/when we can expect a fix.

– Tom

I’ve just installed 66.00, and the problem no longer seems to occur.

– Tom

Yep, everything seems to work fine now.
Thanks for the tip Tom :slight_smile:


That indeed is excellent news!
Is there any timeframe on when this fix would be available in the linux drivers?

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