Several changes. Tested working on Windows 10 GL 4.3 and MacOS 10.11 GL 2.1. - document extensions used in this file - some simple ARB/EXT suffix deletion - stop checking for pre-2.1 features — they’re available! - convert old ARB shader API to the one adopted in GL 2.0 - remove checks for old (pre-R600) ATI cards - choose GLSL version at runtime, between 1.2 and 1.5 - prefer GLSL 1.5 for geometry shaders, fall back to EXT_geometry_shader4 if needed Differential Revision: https://developer.blender.org/D1632