Hi J-S,
Responses below:
[...]
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 think that breaking gl_LightSource usage in fragment shaders is actually a
major problem. On this forum there are three of us who admitted it affected
them. Probably few more did not mention it. How many OpenGL developers
outside OSG community do pixel lighting ? I bet there thousands if not tens
of thousands who were or can be affected in the future.
Its not just a minor issue, so I guess NVidia will do something about this
sooner or later. I hope they will, despite the fact, they did not respond to
my bug report at all ;-(. I am telling myself they probalby did not, because
they already knew about it.
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.
-------------------------------------
Yeah, I thought about the same ;-). Are NVidia continued legacy OpenGL
support statements still valid ?
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...
I think NVidia was adding support for OpenGL 4.0 & 4.1 for Fermi based GPUs
and they screwed something in shader compilers. If this was a minor issue
they could ignore it, but I think its huge problem for many developers and
NVidia should be aware of its importance. So I really think they will fix
it. If they are not and will continue such attitude, then one day ATI will
start to have better quality drivers. And it won't happen because ATI
drivers improved ;-) Btw, I would love ATI/AMD OpenGL drivers improve so we
have a real competition in OpenGL.
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).
Since, I said before I think they will fix it, I can now play a little
devils advocate ;-). I actually think that such OpenGL legacy support policy
prevents faster progress. I think that DirectX has now edge over OpenGL and
now dictates the pace of 3D graphics. This success was partially achieved by
Microsoft policy to do a revolution with every major DirectX release. They
redefined whole API and removed all stuff that did not fit anymore. With
such attitude developers were forced to adapt but they also gained a lot.
With compatibility profiles OpenGL cannot progress that quick. And number
of OpenGL new and older calls & usage combinations certainly makes building
fast & well behaving drivers more difficult. So I would rather like to see
some revolution is OpenGL and adapt my code to pure OpenGL 4.0 profiles than
deal with unexpected driver errors.
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...
As I said I have not heard from them after bug report. But I hope its a good
sign and it means they are working on the issue.
Wojtek
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