"The specific sizes and formats for integers and floats in GLSL are only for GLSL 1.30 and above. Lower versions of GLSL may not use these exact specifications.

"The specific sizes and formats for integers and floats in GLSL are only for GLSL 1.30 and above. Lower versions of GLSL may not use these exact specifications." Pre-1.3.0 was a truly dark era. Lots of really nasty driver and hardware issues lurking around.