   DXT5n, sRGB
  I only see GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, so how do I load compressed normal maps?Also, I assume the GL_COMPRESSED_SRGB will not work with glCompressedTexImage2D since it's a generic rather than specific format, and I don't see any specific compressed format alternatives.  What to do then?   
  A/what precisely is the texture compression format that youre trying to load B/ what card do u haveif u have a nvidia card u can download from their sitenvopenglspecs.pdf it tells u  what card supports what features   ;  Regarding my second question, I don't care what the format is, as long as it's 1) compressed and 2) I get the automatic sRGB decoding that for example GL_SRGB8 for example gets me.   ;  It's possible that 3Dc hasn't worked its way into OpenGL extension-land, even though it's present in Direct3D. Could be a patent thing. I don't see it on ATI's extension specs, and if anyone would have it it would be them.   ;  Any suggestions regarding sRGB then?  Short of doing the color space conversion in a shader (which would make my shaders NOT texture format agnostic)   ;  3Dc compression has been specified in GL_EXT_texture_compression_rgtc and GL_EXT_texture_compression_latc extensions. It is supported on both ATI and Nvidia all DX10 level cards.   ;  LATC would seem to be deprecated in GL 3.1 as I don't see any luminance(+alpha) texture formats in the spec.RGTC is two channel only. That's OK for normal maps if nothing else needs to be encoded, but doesn't DXT5n have some features that decrease visible artifacts for normal maps compared to other compression?  i.e. will RGTC be visibly as good as DXT5n?   ;  RGTC will be much better than DXT5 for normal maps.Read here: http://developer.nvidia.com/object/real-time-normal-map-dxt-compression.html.   ;Quote:Original post by PruneRGTC is two channel only. That's OK for normal maps if nothing else needs to be encoded, but doesn't DXT5n have some features that decrease visible artifacts for normal maps compared to other compression?The difference between 3Dc and conventional DXT5 are twofold: First, compression is per-channel rather than over all channels at once; and second, there's only two channels. The first factor will help with any texture, the second factor makes the first factor not take up so much room. If you want a 4-channel 3Dc you could just do two 2-channel DTX5s... except that that would make the compression 1:1.   ;  Great, so that solves one of my problems.  Thanks!Someone pointed out to me in the OpenGL forums that there's an GL_COMPRESSED_SRGB*_S3TC_DXT*_EXT so I just need to figure out how to check in a dds file header when I'm loading the compressed texture file whether it is sRGB (or if it's not, what the gamma is so I can see if it's closer to linear RGB or to sRGB)   