[Mesa-dev] Naked DXTn support via ARB_texture_compression?

Petr Sebor petr at scssoft.com
Sun Mar 20 13:02:57 PDT 2011

On 20.3.2011 16:42, Jose Fonseca wrote:
> Petr,
> You don't believe that IHVs may have narrow licenses of the S3TC patent. How do you explain the statement:
>     WARNING:  Vendors able to support S3TC texture compression in Direct3D
>      drivers do not necessarily have the right to use the same functionality in
>      OpenGL.
> in http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_compression_s3tc.txt ?
> This is just a piece of evidence. I heard this from several different people now.

I have noticed that warning as well, but my interpretation is that since 
DirectX runtime does not itself implement compression
algorithms at all (it only serves as the passthrough), the OpenGL simply 
has to.

In my view, a vendor has to obtain a hardware license to be able to 
decompress data and optionally, if he cares about
OpenGL - a software license for the drivers,  to be able to compress 
them them on the fly. Otherwise the EXT_tc_s3tc is no go.
This is (I believe) the difference that matters.


Petr Sebor / SCS Software [ http://www.scssoft.com ]

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