Hi Wojtek,
In the meantime I changed the code to use my own (non gl_) uniforms and
this also seems to work. However, instead of array of LightStructs I
rather use a set of arrays each containing single light attribute (for
example diffuse) for all lights. I did it because it allows for better
use of uniform memory.
Yes, that strategy was also suggested on one of the forum threads I read
about the problem.
http://www.gamedev.net/community/forums/topic.asp?topic_id=578784&whichpage=1�
Actually someone on that thread said that bugs in deprecated
functionality were likely to appear often, which to me suggests that
nVidia might never fix this bug because it relates to built-in uniforms
which are deprecated, and just using your own uniforms instead of
gl_LightSource[] works fine, so why should they fix a deprecated feature?
I actually wonder how true that is, based on this text that can be found
on nVidia's site (http://developer.nvidia.com/object/opengl_driver.html) :
-------------------------------------
4) Is NVIDIA going to remove functionality from OpenGL in the future?
NVIDIA has no interest in removing any feature from OpenGL that our ISVs
rely on. NVIDIA believes in providing maximum functionality with minimal
churn to developers. Hence, NVIDIA fully supports the ARB_compatibility
extension and Compatibility profile, and is shipping OpenGL drivers
without any functionality removed, including any functionality that is
marked deprecated.
5) Will existing applications still work on current and future shipping
hardware?
NVIDIA has no plans for dropping support for any version of OpenGL on
our existing and future shipping hardware. As a result, all currently
shipping applications will continue to work on NVIDIA's existing and
future hardware.
-------------------------------------
But then again, that text might just be PR speak and wishful thinking.
If some feature is deprecated (OpenGL 2.x, built-in uniforms, etc.), and
less developers are using it over time, how many resources are they
likely to devote to fixing bugs that appear in that feature?
Of course, from the version number jump, we might assume that nVidia did
some big work on their drivers lately, maybe even a rewrite of some or
all of them. If that's the case, then they might have had to rewrite the
deprecated parts too, and since they most likely tested these parts less
than the others, it could explain why we see some bugs in it at this
point. This is all conjecture on my part of course, but this kind of
thing happens pretty often in development projects...
What do you think? I don't know what to think at this point, but since
we have an acceptable workaround I'm not too concerned. I just hope the
situation doesn't go downhill from here (at least not before OSG has a
good transition path to OpenGL 3+ that we can use).
In any case, let us know if you ever get news from the bug report you
sent. In the past when I've reported bugs they've been rather quick to
respond, but maybe that has changed too...
J-S
--
______________________________________________________
Jean-Sebastien Guay jean-sebastien.g...@cm-labs.com
http://www.cm-labs.com/
http://whitestar02.webhop.org/
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