1GL_EXT_texture_compression_s3tc_srgb 2https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_texture_compression_s3tc_srgb.txt 3GL_EXT_texture_compression_s3tc_srgb 4 5 GL_COMPRESSED_SRGB_S3TC_DXT1_EXT 0x8C4C 6 GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT 0x8C4D 7 GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT 0x8C4E 8 GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT 0x8C4F 9