July 31st Git build - brightness issues

[Enjay]

For some reason, sometimes GZDoom is using incorrect lighting values to render a scene:

Standing in a doorway, everything looks like it is meant to (relatively dull outside):



Move forward a little bit and the outside brightens up:



It's very localised. If I move forward a little more, the scene goes back to how it is meant to look.

I have noticed it a few times and each time I have been standing in a doorway with different light levels in the rooms either side of the door. I don't know if that is relevant or not.

Dynamic lights are also used on the map and these could be relevant. Certainly, disabling dynamic lights stops the problem.

Also, it seems to be related to "Software" sector lighting mode. The effect doesn't seem to be there in other modes (as far as I can tell).

I don't think that I will be able to make a demo map for this because the effect doesn't happen in the same place all the time. One time a particular area will be fine during one play, the next time it won't. For example, without making any changes in the map, I have tried repeatedly since I took the above screenshots to make the effect happen in that location - I can't. However, it appeared in another location that was previously fine.

[Graf Zahl]

I can't debug a screenshot. So how should I fix this?

[Enjay]

I know it's not much (almost nothing) to go on. I'm just flagging up that there is *something* not right and I guess that there's always the hope that it might just be enough for you to make some connections with something somewhere.

The problem with this one is that although it seems to be quite frequent, it isn't consistent. I have seen it 4 times so far during 5 different play sessions and each time it was in a different location in the map. So I can't just make a demo map because the effect cannot be guaranteed to be in the same place across two different plays. FWIW, the most recent time was nowhere near an outside area or a door. I did try making a save game to see if the effect persists across saves but I forgot and altered the map before I checked the save. Now the save won't load. The next time it happens, I'll try a save again.

[edit] Well, I can now confirm that it does persist across saves. Finding a spot where the effect happens, quitting, restarting and loading the save will take you back to a game where the effect happens. Unfortunately, the effect remains sensitive to various conditions. Simply not loading the modeldef for 1 enemy (which was only present in the field of view as a corpse) was enough to stop the effect when I loaded the game again.

I tried running around in the map - with my actors, textures and models all stripped out - firing at stuff and picking things up for over 20 minutes and I couldn't replicate the problem. The whole project isn't easily in a form that I can zip-up and send you ATM. So the save that shows the problem is not much use for now. At least I now know that it can be preserved in a save though.[/edit]

[Graf Zahl]

I repeat:

I can't debug a screenshot. So how should I fix this?

Closing due to lack of usable feedback.

[Enjay]

The map should be released in the next few days (maybe sooner) so perhaps someone will experience the same issue and be able to make a bug report with a save game and everyone will have access to the map too.

That being said, I haven't had the problem myself for a week or so.

[edit] Map released:
http://forum.zdoom.org/viewtopic.php?f=19&t=46718
[/edit]

[Enjay]

No point in reopening this because I still can't get something actually testable to you, but just to record that it still happens. Despite the fact that I didn't ever see the effect in my Gene-Tech mod after the above posts (the mod in those posts was Gene-Tech) I just got the effect with 2.0.04.

It only happens in Software emulation mode.

Depending on which direction I face, the sky will either be bright or not. There is a clear point in the 360 degrees of rotation where the sky changes from one brightness to the other. Facing slightly to the East of this point the sky is dull. Turning West past the critical point and the sky becomes bright.

Sky looking dull:


Turn slightly West:




Unfortunately, attempts to recreate it in an easily testable format continue to fail.

[Graf Zahl]

Hm. That's odd. The software lighting mode is explicitly switched of for rendering skies so this shouldn't happen anymore.

[Enjay]

Curious. Well, it definitely only seems to happen in that lighting mode. All other modes seem to show the sky consistently and correctly (the brighter appearance).

However, my previous post is misleading. I said that the angle the player was standing at was critical. That was true for the position where I took the screenshots but it seems that moving around the map triggers the effect in different ways. e.g. these two screenshots show the effect and the only difference in player position is that one screenshot was taken before walking forwards a few units and the other after doing so.

[Graf Zahl]

The software lighting mode and the sky do not work well together because that lighting mode tends to leave some bad values in variables that do not work for sky rendering. That's why it should be switched off. I'll have to see if something was overlooked. Is this a cubemapped sky or just a regular one?

[Enjay]

Just a regular one. Standard 256x128 texture. No scrolling or anything.

[Graf Zahl]

Ok. Don't expect any results tomorrow but I'll try to look into it on Friday when the Christmas celebrations are over.

[Enjay]

Much appreciated, thank you. Sorry I can't give you something more concrete to test.

Have a good Christmas.

[Graf Zahl]

Can you point me to a map where this happens?

[Enjay]

Unfortunately, no. If I just load the map on its own, the effect doesn't happen. If I load everything for the project, it happens every time, in the same places and very predictably - but that's hundreds of MB.

I've tried pairing it down to get something minimal that I could post as an example but the problem seems quite sensitive. Messing with which resources are loaded seems to affect the problem and, as yet, I haven't found a way of making a package that shows the problem reliably at a size that I can upload. I'll keep trying though.

Actually, forget that. I've got it down to 62MB and still showing the problem. I'll send a PM with a link once the file is uploaded.

[edit]
OK. PM sent

In my PM I also mentioned a second potential problem that this map might show. I found the thread where I originally mentioned this some time ago:

http://forum.drdteam.org/viewtopic.php?f=25&t=2644

More details in the PM.

[/edit]

[Graf Zahl]

Fixed the sky problem.

The other one is a bit nasty.

Normally view interpolation is turned off for teleporting. But as it so happens, this teleport occurs within view of a camera texture - so the camera texture intercepts the flag not to interpolate, resets it and causes the regular view to be interpolated normally - which is clearly unwanted.

Please report this at the ZDoom forum, I'd prefer if Randy could give some input, too, how to change this