1GL_ARB_texture_gather 2https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_texture_gather.txt 3GL_ARB_texture_gather 4 5 GL_MIN_PROGRAM_TEXTURE_GATHER_OFFSET_ARB 0x8E5E 6 GL_MAX_PROGRAM_TEXTURE_GATHER_OFFSET_ARB 0x8E5F 7 GL_MAX_PROGRAM_TEXTURE_GATHER_COMPONENTS_ARB 0x8F9F 8