OK, I don't exactly want to stir up this hornets nest *again*, but a couple of things aren't entirely clear to me and I'd appreciate any clarifications.
As I understand it, the situation is as follows: The S3TC algorithm is patented and therefore no-one can distribute an implementation of the algorithm without a licence from the patent holders. S3TC decompression must be implemented in the hardware (otherwise what's the point), therefore hardware which uses S3TC can be assumed to have a valid licence to use the code, otherwise the patent owners would be down on the hardware manufacturers like the proverbial ton of bricks. As far as I'm aware, the main users of S3TC are modern games with their vast arrays of textures -- presumably such games come with the textures precompressed, or are able to compress them and cache the compressed textures themselves. Presumably again, the authors of the games have paid for a licence to use the S3TC algorithm from the patent holders. Now, if an OpenGL application has a pile of textures already compressed with the S3TC algorithm, then I don't understand why the dri drivers can't simply offer the S3TC interfaces to the hardware, pass the compressed textures to the hardware and let the hardware get on with its licensed decompression of the textures as required. Likewise, if the OpenGL application passes compressed textures to the S3TC API then how it gets hold of the compressed textures in the first place is it's own responsibility -- the OpenGL API just passes them on. This line of reasoning suggests that no software fallback can be provided for S3TC in the Xfree DRI, since such a fallback would require decompressing the textures which would require a patent licence which the DRI doesn't have. However, there should be no barriers to implementing the API in the case where the textures are simply passed from an application to the hardware. Is the reason that this hasn't been done because there a fault in my reasoning (obviously IANAL), or are the DRI developers are just leery of going anywhere near the whole tarball of pain (not being lawyers either) and are happier coding things which don't have patents looming around them? Presumably there's also the issue of hardware documentation to implement the API on top of the hardware -- I'm assuming that this is available obviously. cheers all, Phil -- http://www.kantaka.co.uk/ .oOo. public key: http://www.kantaka.co.uk/gpg.txt ------------------------------------------------------- This SF.net email is sponsored by: SlickEdit Inc. Develop an edge. The most comprehensive and flexible code editor you can use. Code faster. C/C++, C#, Java, HTML, XML, many more. FREE 30-Day Trial. www.slickedit.com/sourceforge _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
