[Mesa-dev] Implement NV_fog_distance for Gallium hardware

[Marek Olšák]

If there are no other concerns, I'll push this on Saturday, including
the nv20 fix from Francisco Jerez.

http://cgit.freedesktop.org/~mareko/mesa/log/?h=nv-fog-distance

Marek

On Tue, Sep 20, 2011 at 7:50 AM, Nicholas Miell <nmiell at gmail.com> wrote:
> On 09/19/2011 10:23 AM, Ian Romanick wrote:
>>
>> I guess the big question is... why?  With vertex shaders, this
>> functionality is not terribly useful.  Over the past few weeks we've
>> been *removing* code like this, so it seems kind of odd to add some of
>> it.  If I'm not mistaken, the only hardware in Mesa that can do this
>> but not vertex shaders is NV10.  Is it really that helpful?
>>
>> I'm not necessarily opposed to adding this, I just want to be sure
>> we're giving it full thought... that's all.
>>
>
> Good question. In the general case, I'd agree with you that implementing
> ancient extensions is a waste of effort, but this one is (AFAICT) an
> extremely low impact change that benefits a number of existing projects.
> It even has new code being written to target it, oddly enough (which is
> what prompted my interest in the first place).
>
> My first pass at this actually skipped the extension entirely and just
> changed the generated vertex program to always use the eye radial
> distance, but I figured that a full implementation of the extension
> would be the correct thing to do, especially when there may be some
> program out in the wild that breaks if the fog distance isn't abs(Ze).
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