Diagnosing Morrowind light pop-in

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CMAugust
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Re: Diagnosing Morrowind light pop-in

Post by CMAugust »

AnyOldName3 wrote: 03 May 2019, 14:29 Does changing the radius change how brightly things near a light get lit?
Not that I can see. A huge radius on something like a travel lantern will not make an area fullbright no matter how big the radius is. A light spell on the other hand is quite bright, with a color close to white, and gives a fullbright effect at large ranges (easily accomplished in-game at a spellmaker). I have no idea how to make an intensely bright light in Morrowind.
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Chris wrote: 03 May 2019, 19:23 One other thing with Oblivion is it uses per-pixel lighting, unlike Morrowind which uses per-vertex (same as OpenMW by default). Per-vertex lighting can cause a light to brighten a surface more drastically, especially with larger polygons since it uses linear blending between vertices, which can make pop-in more apparent.
I haven't found per-pixel lighting to affect pop-in specifically, but it's essential when using fully quadratic lighting as the difference in vertex density between meshes can be enormous.
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As far as pop-in is concerned, switching to fully quadratic lighting made the biggest difference, by far. Vanilla attenuation settings are an absolute garbage fire in comparison. That's not to say quadratic "just works" - pop-in is still reproducible and it makes scenes noticeably darker, especially indoors. Increasing QuadraticRadiusMult to a higher number brightens things up, but pop-in returns with a vengeance.
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AnyOldName3
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Re: Diagnosing Morrowind light pop-in

Post by AnyOldName3 »

I've mentioned changing attenuation and that Morrowind not being gamma-correct makes more realistic attenuation models look bad. CMAugust might want to read this if you're interested in that: https://learnopengl.com/Advanced-Lighti ... Correction

Bear in mind, though that the approach mentioned in that article won't magically make everything look better. It mentions things like environment artists meddling with lights and making them really bright to avoid making other things dim and stuff like that, and it's highly likely that switching to being gamma-correct would require someone to look through the light placement in every cell in Morrowind.
CMAugust
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Re: Diagnosing Morrowind light pop-in

Post by CMAugust »

I am interested; thanks for the link.
Bear in mind, though that the approach mentioned in that article won't magically make everything look better. It mentions things like environment artists meddling with lights and making them really bright to avoid making other things dim and stuff like that, and it's highly likely that switching to being gamma-correct would require someone to look through the light placement in every cell in Morrowind.
We won't really know that until gamma correction exists in OpenMW (pretty please). I'm fairly certain the result will be vastly preferable to any popping behavior either way.

Meanwhile, can we be confident the vanilla use of linear attenuation really the issue here - the sole reason for light pop-in? I tried to mess with Oblivion's attenuation to see if the effect could be replicated there, but it appears to just ignore any changes to attenuation in my testing. Skyrim afaik doesn't have attenuation settings available.

Another curious fact is that (using fully quadratic lighting) while pop-in can still be observed in some cases with a standard torch, the Light spell appears to fare better - I can't detect any pop-in at all.
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Capostrophic
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Re: Diagnosing Morrowind light pop-in

Post by Capostrophic »

Light spell light source sphere radius was deliberately multiplied by 3 to avoid pop-in being as egregious as it is.
CMAugust
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Re: Diagnosing Morrowind light pop-in

Post by CMAugust »

Engine-side? That explains why I couldn't understand it, looking only at the CS. Thanks for the info.
Nobby
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Re: Diagnosing Morrowind light pop-in

Post by Nobby »

I am on OpenMW 0.47, vanilla game, no mods - am I getting it right that:
- light pop-in issue still exists and is yet to be solved?
- current light pop-in issue does not depend on number of sources of light?
- current light pop-in issue is not the one fixed in 0.42 release, which had a note that "Light prioritization on objects now takes the light sources' intensity into account (fixes issues with light sources popping up)"?
- there are more than one variations of the light pop-in issue?

Ald'ruhn Mages Guild:
light is OFF, then ON on approach
light is ON, then OFF, then ON again on approach

I checked, original MW does not have these two exact problems witnessed on the videos.

From some recent Reddit comments I've learnt that some light pop-in issue will be potentially solved in the future, so is it the one(s) captured on my videos?
CMAugust
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Re: Diagnosing Morrowind light pop-in

Post by CMAugust »

There are two ways in which light "pops" in OpenMW. The one in your videos is due to the 8-light limit, which is a limitation in vanilla Morrowind as well, but there is something else vanilla is doing (possibly baked light on scene load) that, for example, makes it handle the lighting in Ald'ruhn Mages Guild just fine.

This thread is specifically about light attenuation, which is just as bad in vanilla Morrowind. It turns out this is due to the fixed function light attenuation formula itself being bad, which Morrowind uses and OpenMW faithfully copies (for now).
Nobby
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Re: Diagnosing Morrowind light pop-in

Post by Nobby »

CMAugust wrote: 24 Jan 2021, 08:46 This thread is specifically about light attenuation
My apologies for bumping, just thought it would be better to use the existing "light problem" topic, than to create a new one.
CMAugust wrote: 24 Jan 2021, 08:46 ... The one in your videos is due to the 8-light limit...
https://youtu.be/YKhfdOxkafo?t=237 - 0.42 OpenMW release video follows the release commentary that "Light prioritization on objects now takes the light sources' intensity into account (fixes issues with light sources popping up)" and states that 8-light limit problem "vastly improved im most vanilla situations".
So I am not completely sure that Ald'ruhn Mages Guild issue is the 8-light limit one on 0.47, unless confirmed by the team coders.

If so, every and each person playing OpenMW should have this issue in Ald'ruhn Mages Guild, I would be grateful if anybody could confirm that they have it too.
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Amenophis
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Re: Diagnosing Morrowind light pop-in

Post by Amenophis »

I'm just tested on latest nightly on Linux. The light pop in still there for years now.
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Nobby
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Re: Diagnosing Morrowind light pop-in

Post by Nobby »

Amenophis wrote: 24 Jan 2021, 14:58 I'm just tested on latest nightly on Linux. The light pop in still there for years now.
Thank you for the confirmation!

Also I've been just explained that by this day 8-light limit issue is indeed still here, but being worked on which is just a matter of time.
https://gitlab.com/OpenMW/openmw/-/merge_requests/232 - one of the possible future solutions, as far as I've understood.
Just leaving this message here for anyone who will bothered with this issue as much as me, just wait patiently and hope for the best.

OpenMW already reached unsurpassed quality level and will shine brighter with each other day.
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