[Mesa-dev] [RFC] [BRANCH] Floating point textures and rendering for Mesa, softpipe and llvmpipe

[Luca Barbieri]

> I think we need to be sure we're not infringing on this patent.  Until
> we know one way or the other I'd prefer that we don't merge this
> branch into master.  In the mean time I'll see if I can learn more
> about the situation and find a way to proceed.

For anyone interested in determining the applicability of the patent,
the following may be of interest.

Note that this is obviously not legal advice, and could merely serve
as a starting point for a proper legal analysis.

First, ARB_color_buffer_float (the only extension requiring
significant work) doesn't actually require that floating point
rendering is supported.
Instead, as issue #22 in the spec says, it merely provides the ability
to ask for them and check their availability, and provides the ability
to disable clamping in several intermediate parts of the pipeline.
Thus, it's likely that just ARB_color_buffer_float, which is most of
the changes, doesn't infringe.

Second, the  distribution of only source code might be non-infringing,
and there is precedent of projects doing this (freetype, ffmpeg, x264)
and Intel lawyers agree on this point according to Eric Anholt.

Also, from the first court decision, it appears that SGI (plaintiff)
and the court agree that the patent doesn't cover software.