Baking lightmaps for tons of room prefabs?

[cyan sphinx]

hey there, sorry if this isn't the best place to put this question, but i haven't been able to find a good solution for this.

basically, i have a system that procedurally spawns prefabs (rooms) using WFC and that part works fine, but performance is absolutely horrendous due to the fact all of my lights are currently in Realtime.
i have over 100+ rooms, and although i've tried numerous solutions, they either don't work, or would be far too tedious to implement; if any of you have experience with this kind of thing, i would really appreciate it.

i can't use Bakery because i have an AMD graphics card and i'd also like to keep the repository public 😔

some stuff on GitHub i've tried (maybe i did something wrong setting these up? i have no idea lol):

• https://github.com/nukadelic/Unity-Lightmap-Prefab-Baker
• https://github.com/Ayfel/PrefabLightmapping

if you can offer any tips or help please do 😭

Baking lightmaps for tons of room prefabs?

[odd knot]

Baking to prefabs should work
But the issue would be visual discontinuities between modules because they get different lighting

TES: Blades devs implemented a lot of clever techniques to mitigate them
https://www.youtube.com/watch?v=KbxiGH6igBk

[cyan sphinx]

it's more about how i should go about making it work.. like i have a base to work off of i just don't know how to make it work, if that makes sense.

if this is useful to anyone, this code was the closest to working, but i was still getting errors and crap i didn't know how to fix (at least in Unity 6):
https://pastebin.com/LArMaVUJ (LightmapObject)
https://pastebin.com/K14DvK1p (LightmapPrefab)
https://pastebin.com/6sKzd9yY (LightmapObjectEditor)
https://pastebin.com/vVSbu7zj (LightmapPrefabEditor)

[odd knot]

Well, not very actionable if you don't specify which methods you are using, or what errors and crap you are getting

At a glance I see modifications to material property blocks, which URP does not support

[cyan sphinx]

time to set it up again :P

i remember i changed some things to be compatible with URP but i think i probably missed some

[odd knot]

So I assume you're not using the AyaFel prefab lightmapping which doesn't have any of that

[cyan sphinx]

i don't remember at all where i got that code from lol

[odd knot]

Anyway, even when modular light baking works technically, practically it's pretty subpar

So you may have to consider ways to optimized realtime lighting

[cyan sphinx]

you think i could use adaptive probe volumes?

oh nvm it's scene-specific

i just don't get how i can optimize realtime lighting with sooooo many lights, like maybe 400+ lights in a map generation

culling helps a bit but i feel like performance is still bad lol

[odd knot]

Should look into them
Generally they're more expensive than baked lightmaps, and afaik the process to load them in with addive scenes is harder too
But if there's a way to attach them to prefabs then they would be better than prefab lightmapping
But maybe not by a huge margin because you'd still have discontinuity issues

[odd knot]

Any examples or more information?
How many lights per module
How big are their ranges
What sort of lighting
How much of them will be visible to the player at once and at what distance

What platform are you targetting

What rendering paths can you use
More importantly have you profiled lights as the cause of your performance issues

[cyan sphinx]

sorry, i don't really have any more examples other than some screenshots of the rooms, since i've been remaking them recently; but i can tell you that to achieve these framerates, i had:

• to be in the build version of the game
• have rooms i wouldn't be screenshotting disabled
• to disable all scripts (except for freecam, and some FMOD stuff ig)

as for those:

• about 7 lights?
• a range of about 15-20
• spot lights with hard shadows and a couple of point lights
• about 2 rooms worth of lights, so like 14
• desktop
• forward+ or deferred (since Forward doesn't support more than like 8 realtime lights)
• yes, i've used the frame debugger and shadows/whatever else related to lighting take up the majority of the draw calls

sorry to dump all this info on ya, i was trying to avoid it lmao

[odd knot]

It's in most cases the info you should present as the first thing

• Forward+ and deferred make lights so cheap that trying to optimize them is practically pointless, beyond limiting their ranges to what's necessary and even then their reach only matters in screen space
• But shadowcasting is expensive no matter what, especially for point lights
• draw calls don't impact performance in URP if you're using SRP batching, so your assumptions about their cost may not be accurate

[cyan sphinx]

draw calls don't impact performance in URP if you're using SRP batching, so your assumptions about their cost may not be accurate

what??? 😭

i did not know this lol

[odd knot]

Rule of thumb is you don't have to worry about batching at all
Having different shaders between meshes is the biggest cost, but not too terrible at that
The more your objects share shaders and the more similar their materials are in keywords, the better

But even a "poorly" SRP batched scene is typically just fine so the effort to combine materials is questionably valuable
SRP batching reduces the cost of draw calls rather than combining them

But what you need is more empirical performance testing

[cyan sphinx]

awesome, thanks for all this :)
i think i may be worrying a bit too much about performance, i have pretty mid-range specs and i mean ~200 fps per room isn't too bad i guess

[odd knot]

My hunch is shadoecasting lights can be problematic even when disabled, but I guess that can vary

[cyan sphinx]

for sure, i think i'll try the project on my thinkpad next😂

do you think i could use light cookies to emulate shadows?

i don't have that great of an understanding with some of this stuff, i think i just need to experiment a bit more and see what looks good (and performs well lol)

[odd knot]

Currently you have no issue whatsoever, if you can afford to lose like 100 fps to whatever you add and still retain playability on medium spec

[odd knot]

Not exactly emulate them perhaps, but improve light source appearance and save resources otherwise

For example if you want a light that illuminates in all directions but casts shadows into the hallway
Points light shadows would be expensive and redundant, and spot light shadows become distorted and lose quality with outer angles over 90°
So there's a logical option to have a 90° shadow casting downward spot light, overlapping a shadowless point light that has a cookie that excludes the spot's cone below it

https://docs.unity3d.com/2019.3/Documentation/uploads/ExpertGuides/Create_High-Quality_Light_Fixtures_in_Unity.pdf not the same render pipeline or toolset but this document demonstrates extremely well how much light cookies can improve light appearance

[cyan sphinx]

woah

thank you so much

i'll let ya know how it performs when im done lighting up 108 rooms 😂

[cyan sphinx]

oh sorry i completely forgot to ask

which light should i use for a ceiling lamp like this? currently i'm just doing 2 spot lights, one pointing down, and the other pointing up at the ceiling, so it looks like indirect lighting. i'm wondering if i could do something with light cookies tho

actually

nevermind i think i have a genius idea

[odd knot]

For testing performance you'd want to light up just one at first representing the average or worst case and repeat it in generation!

[odd knot]

That's something I've used too and it's useful for excluding shadows from the light pointing up
What I described above is the same technique but with a point light cookie instead of a spot
Spot angles don't go above 180°, but point light cookies have no such limitation so you can use one to be a 270° spot effectively for filling in for the "ideal" shadowcasting 90° spot light below it
But if shadows aren't necessary then you need just one point light and combine the spot effect and fake indirect into one cookie

[odd knot]

Do share!

[cyan sphinx]

i forgot what it was lmao, but i think i'm gonna try making a "light cookie generator" that uses the Transform of a light to capture light cookies in the editor

[cyan sphinx]

sort of works 😂

[cyan sphinx]

adding on to this, i've added batch generating for the light cookies :D

i think it looks pretty good, honestly

i'm not sure how to fix the artifacts and weird shadows yet lol

[cyan sphinx]

pain in my ass but i added gaussian blur and metadata to the light cookies so you can easily load them into the tool

[odd knot]

Great ^^
There's also the Camera.RenderToCubemap method

[cyan sphinx]

for point lights?

[odd knot]

It just renders cubemaps, so you can use them as point light cookes or skyboxes or whatever requires cubemaps

[cyan sphinx]

i might add point lights/cubemaps to the tool; i think i'm just gonna put it on the Asset Store at this point cause this has taken me like 2 days and i think it would be a waste for me to keep this private 😭

there's also a ton of use cases for it, i've tried it out on spinning fans, outdoor environments, hallways, pretty much everything

[odd knot]

Automatic mipmaps you get with cubemap textures can be used for blurring by downsampling
If you get seams iirc you may need to play around with convolution and fixup edge seams settings

[cyan sphinx]

😭

actually it'll probably be fun

i've had so much fun making the GUI ngl

[odd knot]

So this renders an image from the light's perspective for effectively storing shadow casters in the cookie?

[cyan sphinx]

yup, it seemed like the simplest way

pain in my ass

[odd knot]

For doing exactly that it seems really good!

The RenderToCubemap is only for producing the cubemaps
To get useful cookies out of it you need a bit of setup to build the actual cookie shape around it

[cyan sphinx]

yeah i did a bit of testing with Point lights but i hadn't added any anti-aliasing/blur methods so it looked really bad lol

do you know how i could fix an issue like this though? like no matter what orthographic size i do it looks strange

i think the first version of the renderer looked wayy better with whatever settings i had originally but i lost it 😂

nevermind sorry i figured it out lol

[odd knot]

You wouldn't use orthographic projection, except for directional light cookies

[cyan sphinx]

whatt 😭

my life is ruined

[odd knot]

Or you can use them but it won't be accurate to the projection
All additional lights are punctual, meaning they project their light as well as cookies and shadow casting from a single point outward

90° angle spot light functionally has a 90° FoV depth camera capturing meshes for the shadowmap

The frame debugger can show you all the shadowmaps in action

[cyan sphinx]

OH MY GOD YOURE A GENIUS

i forgot that existed

[odd knot]

A point light with shadows is 6 90° FoV cameras
That's why the light cookie is the same as a cubemap which is produced by capturing a perspective image of all 6 angles that make up the imaginary cube

[cyan sphinx]

i can't believe i've been doing wrong thi swhole time

i'll let u know how it goes, thanks :)

[odd knot]

Good luck!
Also, for clarity a point light's outer angle would be the FoV of its cookie/shadowcaster camera

Perspective cameras with more than 90° FoV will start distorting the produced image though, that's why such spot lights get very bad quality shadows with shadow casting enabled

[cyan sphinx]

really? this is how it is with hard shadows; i don't think it looks horrible and its at 130°

i want my cookies to look like this so bad 😭

i'm not sure at this point lol

[odd knot]

The shadow resolution looks really high which helps, also the distortion is concentrated into the center of the spot, which is lacking easily visible shadow casting and receiving objects in this example

[odd knot]

What kind of cookie texture is being used here?

[odd knot]

What you had here looks pretty good, although the cookie texture appears to be inverted

[cyan sphinx]

i genuinely have no idea what i've messed up, i only set up version control AFTER it was already like this 😂

[cyan sphinx]

what do you mean? it's a Spot light, i started using Perspective instead, and although i can send the Renderer code here i don't think it'll help :P

i'm wondering if i can write a shader that shows the depth of objects only, and then i can capture with that instead

i'm sure i'll figure it out

[cyan sphinx]

i made it worse