wdas/brdf — pull request #7 by progschj (2012-10-29 16:01:48+00:00)
Title: the AMD glsl compiler doesn't like half as variable name.

"half" is a reserved GLSL keyword and the AMD GLSL compiler therefore doesn't compile the measured BRDF that use measured.func.
This commit changes all mentions of the vec3 "half" to "half_vector" which makes it compile at least on the current AMD Catalyst linux driver.