Diagnosing Morrowind light pop-in

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CMAugust
Posts: 168
Joined: 10 Jan 2016, 00:13

Re: Diagnosing Morrowind light pop-in

Post by CMAugust » 04 May 2019, 03:59

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 » 11 May 2019, 00:27

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.
AnyOldName3, Master of Shadows

CMAugust
Posts: 168
Joined: 10 Jan 2016, 00:13

Re: Diagnosing Morrowind light pop-in

Post by CMAugust » 11 May 2019, 02:54

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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Joined: 22 Feb 2016, 20:32

Re: Diagnosing Morrowind light pop-in

Post by Capostrophic » 11 May 2019, 12:24

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

CMAugust
Posts: 168
Joined: 10 Jan 2016, 00:13

Re: Diagnosing Morrowind light pop-in

Post by CMAugust » 11 May 2019, 12:32

Engine-side? That explains why I couldn't understand it, looking only at the CS. Thanks for the info.

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