[SVN r1250] Rendering bug: floor/ceiling renders wrongly

[Mazter[Qyou]]

In the latest SVN builds (as far as I can remember it started to happen from r1248) some floor and ceiling textures renders wrongly.
I mean after lowering/raising floor/ceiling the texture still renders at the place it was rendered in the start of map.
This does not happed at my GTS250 but happens on my Radeon Mobility HD 5470.
Here are some screens:
http://doom.tc/screens/auto/dbdaa3576aa ... Mazter.jpg
http://doom.tc/screens/auto/5ae60d93827 ... Mazter.jpg
http://doom.tc/screens/auto/e8dd91f98bc ... Mazter.jpg
http://doom.tc/screens/auto/c46edfc51cf ... Mazter.jpg

[Gez]

I don't see how r1248 could possibly cause this, given the only thing it changed was a function in the "melt" screen wiping algorithm.

It's also interesting that it only happens with ATI hardware. Was there a change on this side, such as a driver update?

There are still some older builds available here, so you can try with r1240 for example? Just to infirm or confirm that it started happening with r1248.

[Mazter[Qyou]]

I can't guarantee it started to happen in r1248, because this was the first SVN build I tested after r1218. But I've just tested r1240 with several different IWADs and was playing then for some hours with several map changes, and I can confirm this does not happen in r1240.

[Gez]

Okay, then, time for dichotomic search.

Does it happen with r1244?
-- Yes: Does it happen with r1242?
---- Yes: Does it happen with r1241?
-- No: Does it happen with r1246?

Granted, a dichotomic search on just four samples doesn't save a lot of time, given that in the worst case there's still three builds to test.

But anyway, it should help pinpoint the actual origin of the issue. Thanks for your help.

[Mazter[Qyou]]

I've just found a way of reproducing so it was very simple. But I've noticed that it happened in r1240 too... so I had to check 1.5.06, and it happened in it too! I was downloading more older and older builds... 1.5.00 is the oldest which ran on my notebook with Radeon Mobility HD 5470. And this bug was still here. By the way, I checked all the builds and found one which was supported - it is 1.0.02 (not 0.9.1 and lower nor 1.1.00 and higher were able to run - they just crashed before the game menu). And in 1.0.02 this bug wasn't happening. I checked it out on several maps several times.

EDIT: I created a new config file and this wasn't happening in r1250. Probably some feature cause it and I gotta check which now.

EDIT2: I found the feature causing such problem: vertex buffer while being set to "dynamic". It does not happen if vertex buffer is disabled or is set to "static".

[Gez]

Alright, thanks for your investigation and glad it was solved.

[Graf Zahl]

EDIT2: I found the feature causing such problem: vertex buffer while being set to "dynamic". It does not happen if vertex buffer is disabled or is set to "static".

Yes, that's an old ATI/AMD problem. Reporting GL functionality by the driver that doesn't work right doesn't sound like a smart move to me but it's not the first time I encountered such things.