“Crunch” Open Source Texture Compression Library vs. U.S. Patent (2012)
richg42.blogspot.com
richg42.blogspot.com
https://richg42.blogspot.com/2012/07/doug-has-updated-his-bl...
"Immunity," but not a license. Whatever that is good for.
There's BC6H/BC7 but it's not as flexible and doesn't do normal maps.
Edit: I misread the description of 3Dc and cancel what I said about normal maps being stuck on DXT5. But there's still a lot of use of DXT5 for normal maps, which is a weird thing to see recommended when 3Dc is almost the same but strictly better.
In addition there are licensing and business issues that made Microsoft mandate BCx for DirectX and Google mandate ASTC for Android.
And having both blocks on a GPU would need way too much area.
https://en.wikipedia.org/wiki/Patent_infringement_under_Unit...
Richard didn't apply for a patent himself, so first-to-invent is not applicable either. If he had learned of Doug's patent application, and then made an application of his own, there would have been a legitimate dispute as to priority. Since Richard shopped the library around in 2009, he might have been able to prove that he conceived the invention first. However, Doug might then have argued that Richard had abandoned, suppressed, or concealed it. See this blog post from 2005 discussing a similar hypothetical:
https://www.irmi.com/articles/expert-commentary/the-dangers-...
The technique employed by crunch was effectively a trade secret until its open source release. It's entirely possible that the patent is invalid for other reasons, but my layman's understanding of patent law is that because Richard didn't publish or patent in time, crunch can in fact infringe Doug's patent.