ATI compressed texture formats & auto-compression

[Stephane Marchesin]

On 4/3/08, Keith Whitwell <keith at tungstengraphics.com> wrote:
>
>  >
>  > GL_ARB_texture_compression is supported... So why don't I get a value besides
>  > 0 when getting GL_NUM_COMPRESSED_TEXTURE_FORMATS_ARB? Or am I looking in the
>  > wrong place and the open driver doesn't actually support any compressed
>  > textures?
>  >
>
>
> This is all about the unclear state of S3's texture compression patents as they apply to open-source GL implementations.
>
>  In particular it's not clear if an opensource driver for ATI (or other)hardware can legally compress/decompress the S3TC textures - I tend tobelieve that this is somehow already covered by agreements the hardwarevendor would have with the patent holder, but like I said it's anunclear situation & people tend to be conservative in those cases.

I don't think it's an issue though, since
1. hardware vendors have a license tied to the hardware implementation
of decompression
2. you cannot patent the compression algorithm, by definition of a patent

So I think it's pretty ridiculous to prevent inclusion of this feature
in mesa, but hey...

>
>  To get this working locally, there's some sort of library you can download & plug in yourself though...
>

http://homepage.hispeed.ch/rscheidegger/dri_experimental/s3tc_index.html

Stephane