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deadalive
06-27-2003, 08:38 AM
I posted this query in the beginner forum but I don't think they know so hopefully you advanced users can answer.

Here is the link to the other post. http://www.opengl.org/discussion_boards/ubb/Forum2/HTML/013219.html

I want to know why opengl has EXT_s3tc_compression commands when I read in various articles that if use this compression technology outside of DirectX you are supposed to buy a license from S3,Inc.

Or has SGI also purchased a license? So that every opengl developer using S3tc doesn't need to (like Microsoft did for DXTn).

jwatte
06-27-2003, 10:16 AM
I believe that each hardware vendor that supports the extension has purchased a license from S3.

When you sell an application, it typically does not contain any actual S3 intellectual property if all you're doing is getting function pointers from the OS/API and calling them (rather than linking a library statically). I'd have no qualms over using any publicly documented extension that a driver exposes, although if you want a legal opinion, you should call your lawyer.

Coriolis
06-27-2003, 03:06 PM
The OpenGL driver implementers are the ones that have to license the technology. Anybody who uses that driver implementation is free to use all its features. Similarly, you don't have to pay CompuServe yourself to view GIF images just because Internet Explorer draws them for you.

knackered
06-27-2003, 04:54 PM
What about writing a lib that saves/loads images in the s3 compressed format?

jwatte
06-28-2003, 04:08 PM
That would probably infringe on S3 intellectual property -- unless they only patented a hardware implementation. If you're thinking of doing that, please call your lawyer first... and be prepared to spend thousands on legal research :-(

deadalive
06-30-2003, 06:51 AM
Thanks everyone! I think what jwatte said is correct, card vendors needed to license it not we opengl developers..

Can anyone suggest a backup plan for cards that don't support the opengl or ARB s3tc extentions?

Madoc
06-30-2003, 09:56 AM
I'm a little puzzled here, NVIDIA provide free code for decompressing DXTCs and don't make any mention of licensing whatsoever. What's da dilly?

V-man
06-30-2003, 06:43 PM
Originally posted by Madoc:
I'm a little puzzled here, NVIDIA provide free code for decompressing DXTCs and don't make any mention of licensing whatsoever. What's da dilly?

It's all about licensing.
Everything comes with a license.
If it doesn't, take advantage http://www.opengl.org/discussion_boards/ubb/smile.gif

If you are a hobbyest, student, educator, I would not worry.

Madoc
07-01-2003, 12:02 AM
Well, the lib comes with just the ususual copyright notice and disclaimer. They also seem to encourage modification of it.
Unfortunately (or rather not), I really don't fit into a category that doesn't have to worry about it. Luckilyy it hasn't been anywhere near one of our products, yet.
Do I really need to take this to the lawyers?

deadalive
07-01-2003, 01:56 PM
I too may eventually have to worry about it.

"Do I really need to take this to the lawyers?"
That is the question.. So far I've gotten mixed answers from different people(and to my knowledge none were lawyers.)

zeckensack
07-01-2003, 03:15 PM
You can try the generic compressed formats. That will free you from any conceivable license issues, but you'll lose the ability to ship compressed content.