gl_FrontFacing not working

Discussion created by KeithJeffery on Mar 29, 2011
Latest reply on Apr 1, 2011 by KeithJeffery

One of our testers updated his ATI driver, and our fragment shader stopped working as expected. I updated my driver, and found the issue: gl_FrontFacing doesn't seem to be set to any meaninful value, i.e. testing

if (gl_FrontFacing)


if (!gl_FrontFacing)

both return true.

We're using an old version of GLSL. Our shaders are prefaced with:

#version 110

The details of this video card:

Driver Packaging Version    8.831.2-110308a-115928C-ATI   
Catalyst Version    11.3

Graphics Chipset    ATI Radeon HD 4850