[Mesa-dev] Mesa llvmpipe for WebGL software rendering

[Brian Paul]

On 02/28/2012 02:39 PM, Eric Anholt wrote:
> On Tue, 28 Feb 2012 09:08:39 -0800 (PST), Benoit Jacob<bjacob at mozilla.com>  wrote:
>> Hi List,
>>
>> At Mozilla we've been wondering if we could get a good software fallback for users who can't get hardware-accelerated WebGL. Mesa llvmpipe seems like the best open source OpenGL renderer, right? At least, it performed superbly in our quick tests.
>>
>> Questions:
>>
>>   1. Is it possible for the application to choose between Mesa renderers? Ideally I would like to be able to evaluate the driver blacklist, and depending on that, use either the default renderer or Mesa llvmpipe. Is that possible?
>>
>>   2. Related question: are you planning to update OSMesa, base it on
>>   llvmpipe? Last I checked, OSMesa was based on swrast from an old Mesa
>>   version. An updated OSMesa would offer a great solution to question
>>   1.
>
> I'd rather see us create a software-only EGL platform.  It seems like it
> ought to be easier to maintain than the special OSMesa system that
> developers other than Brian Paul break, and provides a better-known API
> for interacting with the window system.  That also solves 1) by giving
> you an option at context setup, I think.

Re-implementing OSMesa for gallium would be great for people who are 
already using that interface.  They could take advantage of LLVM's 
speed without changing their apps.

But on the other hand, OSMesa is pretty crufty (it's nearly 20 years 
old) and we could certainly do something nicer.  I hadn't considered 
EGL but that's a possibility.

I'll try to take a look at this when I find some spare time.

-Brian