[Mesa-dev] Merge floating to master

Jose Fonseca jfonseca at vmware.com
Mon Mar 7 00:41:53 PST 2011

Ok. Thanks.

My comments to Luca concerning llvmpipe changes still hold true -- this is not how I want this to be implemented in llvmpipe and I'd prefer to see the llvmpipe changes backed out. I don't want the 99% common case (bgra8 unorm) to be slower, just to cover the 1% (everything else).

Otherwise I have no objection to merge the branch, and unconditionally enable the extensions in question for swrast/softpipe/llvmpipe, given that there is prior art of sampling/renderingfloating point textures in software by the patent author's own admission.

I'll leave to others to decide what to do for other hardware drivers.


From: Marek Olšák [maraeo at gmail.com]
Sent: Sunday, March 06, 2011 18:50
To: Jose Fonseca
Cc: Lucas Stach; Mesa Devel List
Subject: Re: [Mesa-dev] Merge floating to master


I think he was referrring to this branch:


It's based on the Luca Barbieri's branch with additional bug fixes and improvements and it's been tested with r300g, which now has *complete* floating-point texture and renderbuffer support, in addition to softpipe.

There are a lot of piglit tests for ARB_texture_float and ARB_color_buffer_float, which test these features:
- texturing and wrap modes
- texture swizzling
- texture border color
- mipmapping and generatemipmap
- clearing
- blending
- alphatest
- clamping controls
all with floating-point formats.

The display list support for glClampColorARB is missing, but otherwise the float support can be considered stable and it passes most of the tests (more than proprietary drivers do).

I constantly keep it in sync with master (recently I have been rebasing it instead of doing git merges). The Luca's commits are squashed to have one commit per feature/component and to allow for easier review. Each commit has its own history for reference.


On Sun, Mar 6, 2011 at 7:09 PM, Jose Fonseca <jfonseca at vmware.com<mailto:jfonseca at vmware.com>> wrote:

First things first: what branch are you referring to exactly? The floating branch doesn't match your description -- it hasn't been updated my Marek or anybody else in a long time.


From: mesa-dev-bounces+jfonseca=vmware.com<http://vmware.com>@lists.freedesktop.org<http://lists.freedesktop.org> [mesa-dev-bounces+jfonseca=vmware.com<http://vmware.com>@lists.freedesktop.org<http://lists.freedesktop.org>] On Behalf Of Lucas Stach [dev at lynxeye.de<mailto:dev at lynxeye.de>]
Sent: Sunday, March 06, 2011 13:13
To: Mesa Devel List
Subject: Re: [Mesa-dev] Merge floating to master

Am Mittwoch, den 02.03.2011, 08:22 +0100 schrieb Lucas Stach:
> Hello all,
> I want to bring up a an issue discussed some time ago. The support for
> floating point textures and rendertargets currently lives in a branch
> maintained by Marek Olšák. It's nice to see Marek rebases this branch
> from time to time, to bring it up to date, but I don't think this should
> be a permanent state.
> We need to discuss how we want to deal with patented features. I doubt
> floating point support will be the last patented feature in the OpenGL
> evolution.
> I think the best way to go is to merge floating to master but only
> expose the extensions in question if the user specifies something like
> --enable-patented at compile time. From a lawyers sight it shouldn't
> make a difference since currently the code for patented features like
> s3tc and floating point support is laying around on the same public git
> servers as mesa.
> Merging this code into master should make it easier to maintain and I
> see no legal problem if we let it up to the user whether to use this
> code or compile his mesa without any patented features.
> --Lucas

This matter won't go away if we ignore it. We will never get full OpenGL
3.0+ compliance if we don't merge in the floating branch.

Attached you will find a patch against Marek's floating branch to hide
the patented extensions behind a configure switch. Please ACK if you
think we could merge in floating or give some opinion why you think we
couldn't merge.

-- Lucas

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