Re: [Mesa3d-dev] texture compression unsupported types..

[Roland S. <rsc...@hi...>]

Brian Paul wrote:
> Dave Airlie wrote:
> 
>> Okay if I have  an i830 that supports RGB DXT1, and RGBA DXT3 and DXT5,
>> how do I tell the application?, if I advertise s3tc do I have to support
>> all 4 types?
> 
> 
> Actually, no.  If you look at _mesa_get_compressed_formats() in 
> texcompress.c you'll see that GL_COMPRESSED_RGBA_S3TC_DXT1_EXT isn't 
> advertised.  NVIDIA's driver does this.
But is this actually legal behaviour? Just because nvidia does this 
doesn't mean it's correct. I can't see anything in the wording of the 
extension 
http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_compression_s3tc.txt 
which says it's ok to implement only half (actually, 3/4 ;-)) of it. Or 
is there a newer version available (the specfication mentions it's a 
draft version)?

Roland