Trouble with Geometry Shaders on ATI 9.8

Hi all,

Before I go bruising my head too much on this, is anyone else having trouble/problems/errors/artifacts working with geometry shaders on AMD/ATI hardware using the new Catalyst 9.8 driver?

The new driver supports ARB_geometry_shader4/EXT_geometry_shader4, but I’m getting results that look (at best) like only the first N triangles per frame get rendered, or (at worst) like only portions of the triangles get rasterized.

I’ll post anything I can figure out on my own here. But if this is a universal problem, then I’ll just wait for 9.9.


ps. This is on a Radeon 4850.
pps. The code renders fine on Nvidia HW.

I’m having trouble and problems, but no errors or artifacts.

Can’t seem to get texture arrays to work.

I needed to add a global precision qualifier (default highp float) to get a FS to compile.

What are your logs reporting? My post-link logs mention vertex and fragment but geometry is conspicuously absent. Otherwise warning and error free…


Just noticed that the FS doesn’t seem to recognize interpolation qualifiers set in the GS (e.g., flat out/in vec4 foo[4]; in GS/FS generates a link error due to a mismatch in interpolation modes).

I had a few similar issues to flashing geometry in GS and some weird transform feedback errors with Catalyst 9.8. But I never tried the whole global qualifier thing.

Catalyst 9.9 just came out and and it seems to have fixed my issues. Although, to be honest, I haven’t had too much time to test it out too well. Try it yourself.

I’ve also found that if you have ATI specific issues, you get better results if you go to
Sometimes the moderator or AMD devrel guys will try to pick up on any major issues and pass it along.