Unknown builtin parameter

Can somebody tell me what this means?

Fragment info

error: unknown fragment shader builtin varying parameter (named gl_FrontFacing) encountered

Shaders failed to link, exiting…



It much likely means that the current GL-implementation can’t use gl_FrontFacing. It’s in the specs, but at least on ATI (haven’t tried with newest drivers), there was no hardware support for gl_FrontFacing.

Accessing the fragment.facing attribute in nv fragment program seems to work just fine. Must be the glsl drivers then.


This topic was automatically closed 183 days after the last reply. New replies are no longer allowed.