[Mesa-dev] ATI_envmap_bumpmap

[Roland Scheidegger]

Am 27.06.2014 14:39, schrieb Brian Paul:
> On 06/26/2014 06:39 PM, Ian Romanick wrote:
>> On 06/26/2014 05:30 PM, Jason Ekstrand wrote:
>>> Right now, the Intel driver is the only driver in mesa that implements
>>
>> Also as far as we can tell... it's the only driver that implements it.
>> git-blame says that VMware added it a looooong time ago... before there
>> was any support for SNORM textures.
> 
> As far as I'm concerned it can be removed.  I don't recall the use case
> for it.  Roland?

IIRC it was needed to support translation of some d3d8 bump map formats
(which still needed to be supported with d3d9) for some project. Either
with that extension or some other similar extension from hell from
nvidia I forgot the name of (ok granted they were useful if you couldn't
otherwise do dependent texturing).
I can't remember though if we actually even needed it in the end, but
certainly I can't see why it would still be useful today.
IIRC it needed to work with the intel driver but I can't remember why I
only added it there - maybe the other drivers didn't have a trivial way
to use the R8G8_SNORM format this needs (there is definitely nothing
driver specific about the extension the way it's implemented).
So, if it gets in the way, it can easily go, I don't think it serves
much purpose today - earlier it probably would have been more useful if
the old radeons (r100) implemented it "natively" (as this is the only
way to achieve those effects there).

Roland