Platinum — Path Tracing in Metal

[winged veldt]

My third path tracer project and first one using the GPU. Also features a GUI scene editor and, soon, custom scene format.
Initially named metal-pt, then renamed platinum because it's a metal with symbol Pt, and also a cooler name.

@quick zealot i have a project thread now

[quick zealot]

NOO WAYYYY

Actually cooking

Oh shit indirect goes brrrr on the second screenshot

what are EVs by the way for the exposure?

Effort values?

Min-maxing pokemons?

[winged veldt]

ye, it's a bit noisy even at 2k samples because backwards pt isn't great at indirect but it's looking pretty good

that one is at +6.7EV

first one is about +5 i think

[quick zealot]

oh I meant what does EV mean?

what is it?

[winged veldt]

oh

[quick zealot]

i just have a scalar for my exposure control, no "EV" thingy

[winged veldt]

actually not sure what ev stands for but it's stops of exposure

+1ev is double the light

you just multiply by exp2(exposure_ev)

[quick zealot]

hmmm okay I see
so yeah -11EV was a lot earlier hehe

[winged veldt]

yeh it's like 1/2048 lmao

[quick zealot]

but then that's *32, that's also quite a bit

[winged veldt]

6 and 2/3 stops is also a lot, but not unreasonable

[quick zealot]

what does it look like with EV 0 ?

[winged veldt]

yeah

5 stops is about the difference between direct sunlight and bounced light in daytime

if you ever wondered why getting nice photos in sunny weather is fucking hard, that's why

the sun is bright

[quick zealot]

That's blender, it looks okay without any exposure modification

But i guess exposure tuning is purely artistic control no? Like, there's no "correct" image and it's all about what looks good or not?

Also Blender sweating a bit with the indirect lighting noise in the first few samples (100)

[winged veldt]

0 and +2

[winged veldt]

yeah mine also looks awful at 100 samples heh

[quick zealot]

How does Blender "get it right" automatically? Auto-exposure? I haven't seen a feature like that in Blender though

[winged veldt]

honestly idk

the thing about the ev scale is it's relative

so "0ev" is not some kind of absolute value, just means whatever your sensor picks up

[quick zealot]

it's there actually but default values just work 🤷‍♂️

[winged veldt]

iirc there is an "absolute" lv scale where direct sunlight is something like 14lv

in terms of exposure in a real camera that usually corresponds to about 1/250s f/8 at iso 100

[quick zealot]

oh and then you can do everything relative to the sun?

[winged veldt]

yeah you sorta use that as a reference point

but for rendering your values can be pretty much anything

as long as they make sense relative to each other you can scale as much as you want

[winged veldt]

yeah the odd thing is it looks about the same for a cornell box with the same light intensity too

so maybe they are doing some kind of auto exposure or they just handle env maps different

[white hatch]

PlatinumSrc 🤝 Platinum

[quick zealot]

Just tried path guiding in Blender also, for fun, to see how much it helps

First is 256SPP no guiding. 2min09
Second is 256SPP with path guiding (all samples both used for training and rendering). 2min39
Third is no path guiding but equal time with path guiding (2min44)

Uncompressed images

[winged veldt]

damn, gotta get myself some path guiding

[old hollow]

Looks awesome 🙂 does it run on any apple silicon Mac? Even M1 Pro? Send a demo over when you have something and I’ll have a go

Also in case no one said, afaik EV just means exposure value

But idk it’s been a while since I did photography heh

[winged veldt]

thanks! should run on anything that supports metal 3, which i think includes all apple silicon gpus

[old hollow]

Ahhhhh yeah mine supports metal 3

[winged veldt]

i don't have a binary, but here's the repo link, you can try building if you want: https://github.com/teofum/platinum

[old hollow]

Also it’s crazy how my Mac can get almost as good fps on my renderer as my pc with a 4070 in it

Xcode?

[winged veldt]

yeh

[old hollow]

Ok mate I’ll have a try

[winged veldt]

sadly lol, but the metal debugger is a must have

[old hollow]

Yeah haha

I use c# is yours c++ or objective c?

[winged veldt]

i think the only dependency you'll need actually installed on your system is openimageio

[old hollow]

Ah ok

[winged veldt]

cause it's an absolute pain to build and link from source

[old hollow]

Did you see my shadows btw in #wip

Haha yeah fun

You’d have to guide me I use rider never done shit with Xcode only have it installed because it’s required for ue5

[winged veldt]

yee looking great! do you have a project thread for your renderer? realtime right?

[old hollow]

Not yet and yeah real time

I wanna switch from openTK to silk.net

Because it supports dx12

😄

[winged veldt]

i only switched from clion because of msl support and the debugger (though tbh i could attach the debugger to a running process but it's not as nice)

[old hollow]

OpenGL on Mac tho

Ahhhhh

[winged veldt]

oof

i just don't bother supporting other platforms lol

[old hollow]

I was tempted to install that Mac specific Linux distribution on as a second os

[winged veldt]

i have a pc but my mbp is more powerful anyway

[old hollow]

Forgot the name but where Mac OS stops gl support > 4.1 this has 4.6 and vulkan 1.3

[winged veldt]

asahi? lmk if you do heh, could be good for testing stuff

[old hollow]

Heh which MacBook you go yeah I mean that one mate

[winged veldt]

don't think they support m3 yet, though

[old hollow]

Got*

Pretty sure asahi flavour of uhhhhhh

Fuckin

[winged veldt]

it's c++ btw, using metal-cpp

[old hollow]

The new one in their homepage lol

Ooooo nice

Which BVH method you using?

[winged veldt]

the driver one

[old hollow]

Was it Tiny? Idk if it was yours that had that in one of the messages

Ah 🤣

Hah

Btw for my gl renderer

I wanna do hierarchical culling

[winged veldt]

though i have wondered if it's possible at all to custom build a bvh and give that to metal's hw rt api

[old hollow]

So parent gets its bounds tested if it passes and should draw don’t bother testing stuff lower down the chain

My frustum culling on a scene with 500 game objects is like 0.006ms on cpu anyway haha

Game object atm includes renderables

I don’t wanna do an ecs until I finish the uni portion of the project

[winged veldt]

nice, i haven't done much realtime (by which i mean i basically did learnopengl and that's it lol)

[old hollow]

You using Assimp?

[winged veldt]

nope

[old hollow]

Ahh 🙂

[winged veldt]

it's stinky and bad

fastgltf

[old hollow]

I did that shadow filter just from knowing a lil bit about how Pcss works

Ah ok

Gltf is nice

[winged veldt]

though i'm gonna be working on my custom scene format next because gltf doesn't support everything i want and is actually pretty slow to load

[old hollow]

Ahhh ok

Well

[winged veldt]

well, not the gltf itself, fastgltf lives up to its name

[old hollow]

You can process with fastgltf and save as your own binary format

[winged veldt]

decoding the png textures for something like intel sponza takes >1m

[old hollow]

Ah shit

[winged veldt]

[old hollow]

I need to add texture loading but first I wanna do a material system lmao

[winged veldt]

(i could multithread it which would make it much faster ofc, but still, i do want my own scene format)

[old hollow]

So I can at least have colours

Ahhhh yeah

Threading in c# is super easy too

[winged veldt]

ye, that's the plan, custom format with options to import gltf (which i already have) and possibly usd and other formats

[old hollow]

I have to learn cpp decently enough to make some weird social network thingy as final project for the module

Yeah 😄

[winged veldt]

not so much in cpp, it isn't too bad though

i'll have to build my own nih thread pool/job system at some point

[old hollow]

Assimp is cool but I only use it because it gives results and supports everything

Ahhh yeah

[winged veldt]

yeh, fair enough, i used it once and found it slow and hated its api

but it does support a lot of formats which is nice

[old hollow]

heh

[winged veldt]

and quite shrimple to integrate

[old hollow]

yeah it's very easy

hang on lemme share some fun stuff 😄

[winged veldt]

you should check out fastgltf tho, it's good

[old hollow]

c# binding?

if it's a c api then it'll probs have a csharp flavour 😄

[winged veldt]

also the author is in this server and a cool frog so you can bother them if you can't find something in the docs lol

[old hollow]

ahhh 🙂

[winged veldt]

not afaik but i think it does have a c api? or it was being worked on, idk

[old hollow]

yeah I don't wanna bug people tho cos like I got in trouble for saying about trying to get some code gpt spat out working lol

[winged veldt]

or just switch to c++ the superior language

[old hollow]

I used gpt to do my pbr but that's all 🙂

cos I don't understand mathematical notation in papers 😄

[winged veldt]

time to learn them maths

[old hollow]

haha well ye c++ is good but meh

I'd rather use rust if I wanted to learn a new language

mmm thread safe by design

borrows et

c

good stuff for if I ever learn vulkan lol

anyway peep this for how I load my assimp stuff 😄

sorry for the big message hang on

oh thanks discord for making it smalleer 😄

the new parent thing may or may not cause issues but probably not as it doesn't matter if it maintains a hierarchy lol

it loads the scene so I don't give a shit until I need to worry about parenting for blender files etc 🙂

[winged veldt]

oh yea rust is my preference for sure, but if i'm doing graphics stuff i'll reach for c++ just because it's kinda the lingua franca of gp

so much more likely to find the right libraries and resources

[old hollow]

yeah

[winged veldt]

if those are assimp apis they look way nicer than the cpp ones heh

[old hollow]

here's light radius turned up far too high

but as you can see no artifacts or issues really as I have per pixel noise (the classic frac(sin shit)

adds a bit of noise but it's ok

I'll try and do materials but I need to shuffle some stuff about

thinking of doing a thickness estimation with shadowmap and projected z to do some sss shit but I need to add some data to the gbuffer aha

gonna try and visualise the depth difference between projection and the shadowmap see if it's feasible to do sss using that

anyway feel free to dm me if you wanna chat 🙂

will try to remember to attempt to compile your pt

😄

at some point

[winged veldt]

sure, lmk if you have any issues

[coral abyss]

i’ve only ever used the metal debugger with programs i built outside of xcode (by starting the executable from xcode, not attaching to running process). is it really that much nicer to warrant using xcode as your IDE?? it’s so shit, you can’t even hover over variables to get info

[old hollow]

Yeah Xcode sucks shit

🤣

[winged veldt]

yeah i am seriously considering going back to clion/cmake and using xcode for debuggging

[winged veldt]

@coral abyss how do you get clion/vscode/whatever to work with metal shaders? i know you can get most of the way there by telling it to pretend it's a cpp file

but iirc you need some additional defines and such

[coral abyss]

i’m cheating by using wgpu instead of writing metal directly

[winged veldt]

ah

i like msl though

it's like the least bad shading language

[old hollow]

Yeah btw it’s asahi fedora

Supports gl4.6 and vk1.3

I want to try and do voxel cone tracing on my windows flavour of the renderer hah

[timid frigate]

@winged veldt why you dont use gulbrandsenFresnelFit()? can you do compare with Schlick approx?

[timid frigate]

I found compare https://belcour.github.io/blog/slides/2020-brdf-fresnel-decompo/index.html#/6/0/2

gulbrandsen's approach looks better

is halton give HUGE advantages in quality?

why halton, not hammersley or sobol?

[winged veldt]

placeholder sampler lol

i'm gonna replace it with a nice fast sobol implementation soon

i just didn't bother yet cause ehh it works

but it's a crap halton stolen from apple's ray tracing example

notice how the scrambling is a texture written with rand() on the cpu side

[winged veldt]

i think i intended to then didn't bother

[timid frigate]

Saint lazyness

[hazy zenith]

The gui looks nice, I gotta add one too.

[jaunty void]

i like the white theme too

but you can do one better 🙂

these drop down thingies kind of ruin it

however, with this simple trick you can let youtubers know:
style.WindowMenuButtonPosition = ImGuiDir_None;

how to hide it 😉

[winged veldt]

tbh i only use it because i dislike the default imgui dark theme and didn't bother to make my own yet lol

will be keeping it as an option, though

[jaunty void]

it does look nice anyway

[winged veldt]

@jaunty void

i think ima do dark theme now

working on ui shit for a bit will be a nice break between all the renderer stuff and refactoring the entire data model

i'd like to get icons in as well, afaik the easiest way to do that with imgui is an icon font but i'd rather have my own custom icons and if they can have color even better

[jaunty void]

please do 🙂

[winged veldt]

dark theme wip

also trying out a nice green/teal accent color, blue is good but a little too generic

[jaunty void]

the mac border ruins it

: >

[winged veldt]

ye, i should figure out how to remove the titlebar and just keep the traffic lights

like imhex

[jaunty void]

borderless binbow perhaps and then 3 custom buttons ye

[winged veldt]

they're not custom

those are the native buttons, pretty sure there's a window mode in macos where you can keep the buttons and just remove the titlebar

[jaunty void]

i see, but it also looks like the menu is drawn into the non client rectarea then

ah that could be a cocoa thing perhaps

[winged veldt]

afaik it's borderless with the buttons as an overlay

[jaunty void]

i mean you can do that on windows too at least

we could check imhex : >

[winged veldt]

ye

does it use sdl?

[jaunty void]

i dont think so

lol https://github.com/WerWolv/ImHex/issues/77

looks like they have custom backends for each platform

    source/window/window.cpp
    source/window/win_window.cpp
    source/window/macos_window.cpp
    source/window/linux_window.cpp
    source/window/web_window.cpp

macos uses glfw

[winged veldt]

ah, ima have a look

[jaunty void]

nah they use glfw for everything

just some custom shizzle per platform it seems

[winged veldt]

telling sdl to make the window borderless loses the traffic lights and rounded corners too

sadge

tbh i can probably hack sdl some more

i've already added custom events to it for touchpad zoom lel

[jaunty void]

wurst case you add some custom title bar which handles mouse capture for moving it around

and the system buttons

[winged veldt]

ah apparently glfw provides access to the cocoa window object

wonder if sdl exposes that

[winged veldt]

@jaunty void mission accomplished

now i need to add dark theme to the viewports as well

and a custom light theme

i think i can get fancy and make it use the system theme

[winged veldt]

now supports viewport theming, couple more things to tweak but it's looking pretty good

[timid frigate]

Is sdl needed? W/o cant be?

[quick zealot]

How are you doing the outline?
There seems to be a weird thing happening where the small dragon pick ups the outline here

[hazy zenith]

Outlines are hard

[winged veldt]

i use sdl2, so if they did i could've just yoinked their code

i pretty much still did, just had to find how to get a handle to the cocoa window object from sdl2

[winged veldt]

that's intentional, actually

what i'm doing is fairly shrimple and works super well

i just write a secondary uint16 framebuffer with the object ids for each mesh

then in a later pass i run a simple edge detect kernel on that fb, color the results (selection color if any of the pixels match the selected object id, gray otherwise) and merge it into the main framebuffer using the edge detect value as the alpha channel

having that framebuffer also lets me select objects by clicking on the viewport without doing a raycast or anything, as i can just read back the pixel behind the mouse cursor to get the object id

[winged veldt]

btw this is the reason i have uint16 object ids lol

i'll have to upgrade that to u32 eventually, that fb isn't too big anyway

[jaunty void]

that looks neat

i also like the teal/peach or whatever you call those colors 😄

[winged veldt]

if your peach looks like that don't eat it

[jaunty void]

😄

[quick zealot]

https://hal.science/hal-02158423/file/blueNoiseErrorsTemporal.pdf

Any thoughts on that @winged veldt ?

[winged veldt]

oh looks nice

i'll read the full thing later, might be interesting to implement

it's always heitz isn't it

[quick zealot]

hehe ye

[winged veldt]

i wonder if it works well with the blue noise sampler from that other paper

[quick zealot]

one thing that bothers me is that this is only relevant at low SPP count
I'd expect 64 or more to show barely no difference

and I don't expect my offline renderer to produce anything that useful below 64 SPP (although this may actually be debatable with ReSTIR shenanigans)

[quick zealot]

If I understood correctly, this paper is completely independent from how you actually generate your random numbers during integration

from that other paper
which one?

[winged veldt]

yeah seems to be

so i'm wondering if they sort of synergize to give even better blue noise characteristics

[quick zealot]

oh okay

[winged veldt]

ah, didn't check results

i'm on phone so i just read the abstract heh

[winged veldt]

i'll send link when i get to my pc

[quick zealot]

well the thing is just that with more and more SPPs, the noise disappears so blue noise or not, you can't really tell at some point

[winged veldt]

yea

always some noise left though, so why not make it better

[quick zealot]

ye I guess that's right
"give it a shot" is probably the best answer

[winged veldt]

ye

soon™

[quick zealot]

always

the soon™ todolist is getting longer and longer

[winged veldt]

it do

still stuck on getting the scene stuff right

and probably end up rewriting it 3 more times anyway

[quick zealot]

the custom scene format?

[winged veldt]

not yet, that's the next bikeshed

this is the internals, all the code for handling the scene graph assets etc

i ended up using entt for the scene graph which is nice since the ecs model makes it super easy to extend with new stuff should i need to

asset manager otoh is a pain

i'm still debating how to handle it exactly

i think i'm just going to keep my own ref count because it's the most strsightforward way to get the features i want, but it also means a lot of interconnected code

[quick zealot]

bruhhhh engine management stufff

helll nahh I'll keep my disgusting architecture xD

pray in the trustworthy 1-level BVH no instancing no scene graph no nothing 🙏

[timid frigate]

notes of one implementation
https://gamehacker1999.github.io/posts/bluenoiseerrors/

and one more https://github.com/gao-duan/BlueNoise

[winged veldt]

alright, after some more thinking about the use case and implementation i think i've arrived at an asset management model that should work pretty well without being too complicated

one thing i noticed is that having ids as handles to resources is far more flexible than pointers, so i'm going to keep that and avoid using shared_ptr for everything even though it would make parts of the code cleaner

also, i need some assets (like individually imported textures, or user created materials) to live on regardless of whether they are in use or not, as it's entirely possible for them not to be in use when created, but i also need a way to quickly clean up imported assets (ie from a gltf) which are potentially very large with 100s of textures, meshes and materials

then there's the issue of manually removing assets which invalidates references to them

considering all that i decided to keep my current implementation of an internal reference count, dropping assets when they are orphaned, and simply add a "retain" flag that can be toggled on and off for individual assets which tells the asset manager not to drop them when the ref count hits zero

imported textures and anything user created will be retained by default, anything from a gltf import will not, so removing it from the scene will drop any assets that haven't been manually retained or used elsewhere

and as for the reference issue, i'm simply going to stop reusing ids (don't think i should ever run out of uint64...) and invalidate references to deleted assets (probably by just removing the key from the assets map but not the refcount one)

i can deal with invalid references later, probably just culling those objects from the scene when rendering and adding a warning to the ui

[quick zealot]

for reference, iirc Blender for example keeps everything alive until you ask for a cleanup of unused assets

oh wait NVM you're probably going to do that for user assets and immediately clean up unused GLTF assets as you say below

[winged veldt]

yeah, i can easily implement this for retained assets

and even add an option to retain gltf imports so it behaves like blender

i wanted to have the auto delete for imports though, cause importing and deleting gltf assets is a pretty common use case and it's trivial to implement once the ref count is in place

[full hornet]

did you do the ui framework your self or you used a library ?

[winged veldt]

dear imgui

rounded corners and a nice font go a long way

[full hornet]

if this is imGui then i will never have to worry about ui at all...

[winged veldt]

oh yea people do some impressive stuff with imgui

this is imgui as well

idk at which point you're better off writing your own ui, though

imgui is rather limited when it comes to layout (haven't run into those limitations yet, though)

[quick zealot]

Did you find what paper that was btw?

[winged veldt]

oh ye i frogot https://hal.science/hal-02150657/document

[quick zealot]

Yoooo Lyon university that's me

So that's basically concurrent work to the other paper no?

[timid frigate]

One more similar
https://abdallagafar.com/publications/gbn/

Ahmed's Owen is good

Sorry wrong link
I mean this
http://abdallagafar.com/publications/zsampler/

[old hollow]

Btw does hw rt work on M1 Pro?

I can’t remember if it does

All I know is I’m enjoying pissing about with rust and (for Mac) metal even tho wgpu abstracts the balls off api specifics heh

Tempted to do bdpt but would need to know specifics so I can adjust to make it the best it can be per platform heh

[quick zealot]

Everytime I see "hierarchical" I can hear my GPU screaming in the background though

hmmmmm actually they seem to suggest it's fine for GPUs with their hashing approach

nice

That's white noise at the top

and FFT at the bottom

why isn't the FFT white noise too?

Hmmmm I guess it's the emissive quad actually

[timid frigate]

implemented here https://github.com/MomentsInGraphics/vulkan_renderer
described here https://momentsingraphics.de/ToyRenderer3RenderingBasics.html - search for "Ahmed"

[winged veldt]

nope

the apis do work iirc, but the gpu doesn't have rt cores

rt hardware is m3 and a(whatever-is-in-the-iphone-15-pro) onwards

[winged veldt]

oh, if the 'Z sampler' in this paper is the same one described in pbr book 4ed i implemented it in yart, works great

it's hard to make it performant on the gpu though, iirc

i'll have to read the paper to see if they have any notes on a gpu implementation since pbr book doesn't

[old hollow]

ohhhh right ok 😦

rip

😄

also I'll post in wip again, got a triangle drawing 😄

[winged veldt]

assets are being managed

took a while because this is a major rewrite of the entire scene architecture, but the new code is much cleaner and should scale much nicer as i keep adding stuff

being the first major refactor i did it was also a nice test of my overall architecture, i think it went pretty well as even though i completely overhauled the api for one "module" the changes to the other parts (ui, renderers) were limited and quite simple which tells me the "contact surface" between modules is small

[old hollow]

Nice one

Looks good, can you path trace in the “editor” viewport or is it limited to that lil output window?

[winged veldt]

it's on its own window, but it can be resized

at some point i might add a "live" pt view, but it's not a priority at the moment

i think i'm going to make the ui a little nicer and start working on the scene format

big render window

(imgui docking is great)

i have to see if imgui has an api to save/restore dockspace state so i can have workspaces kinda like blender

[hazy zenith]

Doesn't it save stuff to imgui.ini automatically?

[quick zealot]

Yoooo Blender soon

[winged veldt]

yeah, i mean in memory within the application

ig if it saves it to the file that must be in memory somewhere as well

[hazy zenith]

Oh I see what you mean

[winged veldt]

took way longer than it should have, but i added a nice grid display for textures in the asset manager

[jaunty void]

theres even a demo of it in ze imgui demo -> examples menu

[winged veldt]

there is too

fuck

[jaunty void]

: )

it (yours) looks cool

[winged veldt]

ye, but i'm probably gonna look at the example code and rewrite cause that supports pretty much all the features i was gonna add anyway

and looks cleaner than my cursed table shit

ima keep the layout and texture preview, though

[jaunty void]

aye

[winged veldt]

looking nicer now, and it supports showing all asset types at once + multiselect

ima add some filters and a preview/properties panel

also, sdl is pissing me off, the scrolling behavior sucks dogshit

[full hornet]

please, how much time did it take you to build this engine +
how many years of graphics programing do you have ?
did you build an engine before it ?

[winged veldt]

ehh been working on platinum on and off since... november last year iirc? progress has been kinda slow because life keeps getting in the way though

[full hornet]

so you have 1 year of experience in gp ?

[winged veldt]

been doing gp somewhat seriously for just over a year i think, this is my third path tracer in that time

i spent most of last year working on https://discord.com/channels/318590007881236480/1253906693989994549

this is the first one with an actual ui, scene editor etc tho so still pretty new to the whole thing

i did some gp related stuff as far back as high school almost a decade ago now but few and far between (a couple very crappy ray tracers, a software rasterizer and super basic opengl stuff)

most of my programming experience is in webdev actually

[full hornet]

hopefully i can pull something like this in 3 years.

thanks for the answer !

[winged veldt]

don't worry about that tbh, take your time

[timid frigate]

php? node? or frontend?

[winged veldt]

frontend, mostly react/nextjs stuff but also some node backend stuff

[timid frigate]

I'm on webdev backend - node.js mostly

webdev for money, raytracing for fun

[winged veldt]

frfr

[spice frost]

if only ray tracing for both fun and money 😭

[shrewd frost]

just wanted to say the intel sponza render looks really nice on the cover photo

[winged veldt]

finally everything works with the new rewrite + asset manager

time to work on the actual scene format next

i'm thinking of combining json for the scene hierarchy with a binary dump of mesh/texture data in the same file

splitting into parts should be trivial with a shrimple header

[winged veldt]

got a quick json export test working, i'll refactor tomorrow to move all the serialization code to a different file/class and complete the scene export with materials etc

then just need to figure out the binary part, i think i'll just add some properties in the json with the byte length + offset of each buffer/texture

then i can have an extremely simple header (just a uint64 with the length of the json in bytes), loader takes the json bytes, parses that, then reads in asset data as needed

i might actually do two formats with one being json+sidecar binary file just for ease of debugging

i really am just reinventing gltf lmao

[timid frigate]

do you export with printf or some library like simdjson?

[full hornet]

why don't you addopt glfw as your engine format then ? (or is it for fun ? )

[winged veldt]

gltf materials don't support the properties i need, and texture encoding/decoding takes forever with large scenes

intel sponza takes ~30 seconds to load in and most of that is png decoding

granted that is single threaded, i could bring it down to 4-5 seconds by decoding on all threads (and eventually will) but i'd rather not have to deal with texture decoding at all

[timid frigate]

you can repack textures to ktx for example and cache and in next time when you load scene you can check cache exists and load cached. Load time can be smaller

this algo is implemented here https://github.com/gameknife/gkNextRenderer/blob/a5fe38148e7c7bb4a1cd98814e6b05bc8d1070f2/src/Assets/Texture.cpp#L202-L354

you can cache slow pngs only. jpg loads faster

[winged veldt]

or i can ditch gltf altogether, making a scene format is not hard

no decoding algo will be faster than memcpy

[winged veldt]

json side of the scene format is done

now just need to do the binary dump for buffers, textures etc

should be simple enough, just write the data to a file and store the offset/size for each one in a map, then write that to the json

[winged veldt]

added binary data file, now just need to write the code for loading scenes from these files

it saves pretty quick, but the downside of doing no compression/encoding whatsoever is the files are beeg

intel sponza is 7gb compared to 2.5gb glb

[timid frigate]

Did you plan to use wuffs for faster images loading or pkd images formats like bc ir astc?

[winged veldt]

i'm not gonna bother with wuffs, no docs

might look into some trivially decodable format in the future but for now file size is a non issue

[old hollow]

Gpu can decode some compressed formats btw 🙂

Bc6h I think it is?

[winged veldt]

ye, i might look into compressed texture formats later

[old hollow]

Yeah idk if there’s much benefit for something like a path tracer where you ideally don’t want compression artifacts etc but ye

[winged veldt]

it's not lossless?

haven't looked into it at all, file size is not a concern atm so i'm just dumping texture data to a file lol

i will eventually multithread gltf loading though and if it's fast enough i might use the same code to encode/decode images for my format

it's flexible enough that adding options should be trivial

[winged veldt]

scene loading done, i call this a big success

Loaded scene intelsponza in 3332 ms
Import glTF sponza-new-ivy in 23559 ms

quick profiling tells me the loader is heavily i/o bound, it is reading 7gb of uncompressed texture data after all

ofc gltf import can go much quicker if i do it multithreaded (and eventually will), would probably get down to 5ish seconds on my m3 pro

i'll have to look into possible lossless compression algos for textures that are very quick to encode/decode, or metal's gpu encoding, might actually make the loading quicker as it's i/o bound

anyway, i have a scene format, that's enough for now

time for fun post processing stuff

[winged veldt]

added live editing for post processing settings, now everything can be changed during/after rendering

also exposed agx "look" parameters, though i want to add additional post processing steps next (including proper color grading)

[old hollow]

Pls add davinci resolve style colour grading guff

😅 just modify the colour picker a wee bit eh

Looking very good

[winged veldt]

never used davinci resolve, what's it do?

it's video editing so probably pretty complex stuff

i'm thinking of doing a lightroom style thing where you can modify curves, but idk yet

[jaunty void]

why does that look so neat

[winged veldt]

what part lol

i forgot to clamp the agx saturation slider and you can use it to invert the colors

[winged veldt]

made some ui changes to put all the labels on the left, the imgui default of having labels to the right of the controls annoys me

[jaunty void]

the imgui parts 🙂

[winged veldt]

heh thanks :)

i've been doing ui dev/design as a job for half a decade lol

[jaunty void]

: )

[old hollow]

basically that, but instead of just curves you have colour wheels for the highlight, midtone and shadows

I guess just generate a gradient from highlight to mid to low and map it using the image luminosity ? 🙂

[winged veldt]

ah, yea, lr has that as well

actually might be fun to implement

[old hollow]

yeet

[winged veldt]

though, anything color related in the ui has the ever present imgui skill issue of not being in srgb

[old hollow]

oh yeah it's diff 😄

and aha yeah

wait what does imgui use? oh yeah srgb ok gotcha

[winged veldt]

imgui is in linear color, doesn't do any srgb correction

[old hollow]

yeah

[winged veldt]

kinda makes sense because of how it's designed but uhh

[old hollow]

so I guess uh, custom imgui shader? 😄

with per-widget toggle 😄 😄

good luck with that one 😄

[winged veldt]

i'll figure something out lol

[old hollow]

btw can you upload an executable build so I can try without having to compile it myself? when you get time 😄

I've got an m1 pro 🙂

unless

clion is what you use yeah?

I can try to compile it with that, hopefully it works ha cos otherwise I ain't got a clue how to make it work 😄

will give it a go anyway :)))

[jaunty void]

ive seen a color wheel thing like those somewhere in the imgur galleries

[old hollow]

booo ;-; missing openimageio

;-;

it's homebrew'd but shouldn't it be included in the repo ?

rip

you should try to find some t ime to set up github actions and have it build into a mac app automatically 😄

[winged veldt]

ye, it's cmake

[winged veldt]

it's a giant pita to build from source

[old hollow]

Aw shi

Can you do a build or help me build it? When you have time- I wanna try it haha

[winged veldt]

should just build with cmake tbh

assuming you have oiio installed via homebrew

[winged veldt]

added the flim tonemapper and boy does it expose a lot of parameters

@burnt peak you might be interested in this one, it seems to be a full on film simulation with negative+print much like you've been looking at

[burnt peak]

oh yeah - is this the one?
https://github.com/bean-mhm/flim

[winged veldt]

ye, that's it

[burnt peak]

I watched that guy's youtube video - good stuff

I more or less expanded on what he described.

it's actually very similar to agx

[winged veldt]

implementation is a fair bit more complex though, agx is very simple

[burnt peak]

except he uses a simple sigmoid curve

ehh - sure, he goes through the trouble of kind of modeling everything in detail, but the actual curve is simpler, and reused for every channel

unless it's evolved since that video

[winged veldt]

yea, more complicated model, simpler curve

though i do like that the curve can be adjusted with just two points, though

[burnt peak]

that must be new

or is it? I think in the video used smoothstep - maybe just as example though

[winged veldt]

yea it's not smoothstep

uses a sigmoid curve with a linear segment defined by two points

[burnt peak]

ah

did you rewrite the whole thing for c++?

[winged veldt]

msl, so basically yes

based on the glsl version

[burnt peak]

awesome

I'm going to try fitting some LUTs for the second stage of mine and see if that goes anywhere

[winged veldt]

ye, it's just an example lol

[burnt peak]

ah - cool
I'm blind

I tried a 7th order polynomial with added crosstalk and it's still not quite enough - so I'll pull all the saturation-related stuff out and leave that for the lookups

I don't know why I'm so stuck on this, but I'd really like to have something flexible enough for specific profiles

[timid frigate]

@winged veldt what tonemappers you prefer to use?

[winged veldt]

i'm in the process of trying them out rn lol

i like agx, looks nice for most scenes

flim is neat but it has so many parameters it can be a little overwhelming tbh

i also added the khronos pbr one but i don't really like it, it's fine if you just want a look as close as possible to no tonemapping but it doesn't look very good imo

will try tony and maybe add an aces fit but that's for tomorrow lol it's like 4:30am

[timid frigate]

What you think about uncharted2? Some times ago I like it a lot

Uncharted2 have lack of contrast but cover more colors

[old hollow]

Any guide on that or is it just brew install <pkg>

I think I’ll have a try later on just on my way to uni then got a lecture at 11 I think ?

[old hollow]

ok so it seems

the version of openimageio you use is out of date, how can I install the specific version in your project, 3.0.1.0 as I can't seem to figure it out? 😦

@winged veldt

got it mate, figure out how to pull the specific bottle 🙂

ok so you have a nasty dependency on a local file

(:

just replaced your username with mine as I installed the font heh

ok well I got a basic scene rendering that I set up and exported with blender, but the MIS + NEE render mode does not produce anything besides black

😦

Btw mate

Replace /users/leo with $user

[old hollow]

Simple brdf sampler works ok with an emissive sphere

Btw, make use of imguizmo save yourself hassle of making your own manipulator 🙂

Overall I love the ui, and found it easy to use after the initial headache and brew being dumb and not allowing you to specify a version like it used to

But yeah keep it up:) will you be adding lights to your editor next? Could add ies profile support as an extra fun thing 🙂

[dense jacinth]

~

[winged veldt]

oops i forgot to remove that from the very first commit lol

iirc ~ didn't work for some reason? hence the absolute path

but ye, gotta fix that

[winged veldt]

ye planning to add soon

[winged veldt]

weird, can you send your gltf?

or scene

[winged veldt]

that would be a nice thing to add ye, i do plan on adding support for spotlights etc at some point (no point/directional lights though)

you have any good reading on that?

(btw, the reason i don't include the font with the app is because of apple's licensing not allowing redistribution)

[old hollow]

It has an area log it on it but other than that no fuckery haha

[winged veldt]

send ze file

[old hollow]

Ah ok and yeah gimme a sec I’ll send it over 🙂 just vaping then I’ll go sit on laptop, also I got 3/3 for the lab I was in, it’s c++ so I felt a bit bewildered haha

[winged veldt]

emissive surfaces are the only type of light supported, other than hdri

[old hollow]

I can understand c++ decently enough

Also it still didn’t work when I added a sphere with emissive

I’m on M1 Pro 8+10

I believe those are the core counts, but yeah I guess something doesn’t like me if it’s not working, but as far as the ies goes, I asked ChatGPT to help me convert the spherical encoding of the ies into 2D cookie 😬

It doesn’t have hw rt but it falls back so idk what’s up unless the scene is just weird breaking it gimme 5 mins I’ll send the glb

[winged veldt]

yeh, unless there's something in the nee path that's not supported on m1?

but afaik all apple silicon macs have the same feature support

[old hollow]

Hmmm yeah I’ll send the file just getting a coffee 🙂

alright, so the machine is overheating so I got water, let me upload the file 🙂

there you go hope that works ok with it being discord :V

it's just a plane and a cube lol with an area light and camera 🙂

btw, just fyi, the only way to rotate camera is using two fingers on the mac trackpad, there's no way to use an external mouse 🙂

but I guess that's just because it's what you use 🙂

I wouldn't have thought there'd be any difference, are you using some sort of mac specific multi touch api? )

also for me at least, selecting in my scene glb - I can select the plane, but clicking the cube does nothing 😄

playing about with it, the selecting seems to completely stop working heh

[winged veldt]

well the scene has no lights for a start

blender's area lights are not geometry, so i don't support that

works for me if i add an emissive sphere 🤷‍♂️

you were setting emissive strength on it to something other than zero, right?

[winged veldt]

this might be because of how the outlines are rendered, if you don't see the outer edges of the plane both selections look the same, check the scene graph to the left

[winged veldt]

and ye, no external mouse support cause i don't use one so uhh i don't care

might add later but it's a very low priority

mice on macos kinda suck ass anyway

[old hollow]

nope, even with an emissive sphere it only renders on simple for me

[winged veldt]

(and yea, i'm using the touch inputs for scrolling, also modified sdl2 to add the apple magnify event for zoom)

[old hollow]

😛

[old hollow]

yep

[winged veldt]

oh that's weird

might be a hw support thing but i don't see anything in the support tables to suggest that

[old hollow]

I can show you a video 🙂

[winged veldt]

sure

[old hollow]

yeah, idk :/

uuhhhh wtf

it works now??????

[winged veldt]

[old hollow]

the fuck

I did the same exact thing as I did before

with the emissive stuff

it was rendering black before and now it works?????

uhhh weird

however

selection is very weird

I'm in fullscreen btw

[winged veldt]

how so

works fine for me

the way i do outlines might be a little confusing ig

[old hollow]

it's not the outliens

I'm constantly clicking in that video

can't select the cube by clicking it

[winged veldt]

oh that is uhh yeah not supposed to happen lol

[old hollow]

😄

[winged veldt]

wait

did you happen to move the window to an external monitor by any chance

and is that monitor low dpi

[old hollow]

oh I have an idea, are you by any chance using your mac in a specific res?

no this is on my native display

[winged veldt]

huh

weird

[old hollow]

but the res is higher than default mac res

I have it higher than the default

😄

[winged veldt]

cause iirc i don't support display scaling after startup

but it should detect properly on start

[old hollow]

yeah I didn't move it anywhere

oh right? so if I maximise the window it breaks?

[winged veldt]

nah

that should be fine

...unless i just forgor to scale properly there

oh yep

i just hardcoded a 2

well ima fix that

[old hollow]

yeeeeeet

hahahaha

this is fun 😄

not many people have tested this right? so some things that work for you just by chance don't work for me, we be fixing bugs today 😄

[winged veldt]

how are the render times on an m1 btw

[winged veldt]

yeah you're the first

[old hollow]

I wanna know why it's not working sometimes with MIS NEE

haha 😄

yeah well I don't mind testing cool shit

and uh I'll make a vid 🙂

[winged veldt]

just don't expect the bugs to get fixed quick cause i'm working on my postprocessing

lol

[old hollow]

ye, the MIS NEE is ropey

this is what happens when using an emissive material on a sphere added from the editor

[winged veldt]

that's odd, works fine for me

[old hollow]

and with the cube emmissive from the gltf file this happens XD

lmao something ain't right 😄

oh wait a sec

what is a sane value to use for emissive strength

because before I had to have it high

oh it was an issue with mat

but yeah your sphere and I guess cube that can be added from add menu

seems to break stuff 😄

[winged veldt]

huh, it shouldn't

but uhh maybe i broke the version on master lel

[old hollow]

and it's working again kek

weird

ignore the white floor

I had emissive on the mat

[winged veldt]

try pulling the pp branch that's the one i'm working on

[old hollow]

but there's deffo a bug where emissive sucks light out of the scne 😄

yeah I will try that 🙂

MIS NEE seems to work ok

let me try do what I did before to replicate the bug

pls, when you get time btw, add support for maximise without fullscreen by double clicking the title bar 😄

[winged veldt]

uhh don't set it to negative ig lel

[old hollow]

I didn't 😄

[winged veldt]

oh yea

i use rectangle so i forgot about that completely

but ig since i hide the titlebar that's gone

gotta figure out how to bring it back

[old hollow]

hm seems to be fine now so I guess it wasn't a bug just my own error 😄

or it's a tricky one, but yeah weird 😄

[winged veldt]

wontfix: unsupported hardware

(unsupported hardware is anything that's not my own laptop )

[old hollow]

also I like how you've got a lut generator 😄

[winged veldt]

do let me know if you figure out what might be causing it more specifically though lol, if i can reproduce i'll fix it

[old hollow]

and ye, I guess it's fine if you don't care about others using it, it's a personal fun project heh

[winged veldt]

oh yea, that's internal but i just made it part of the thing cause i already have all these parts might as well reuse them

[old hollow]

and yeah I'm not sure, like setting a light to negative just makes the whole scene black in the render view instantly

but in the bugged time, it would take colour away slowly 😄

and that was without negative in the emissive

[winged veldt]

oh that sounds like nans

[old hollow]

so testing if I ahd it negative proved wrong 😄

lol yeah 😄

haha

[winged veldt]

not the nans

[old hollow]

😢

[winged veldt]

oh well i'll have to check it out later lol

[old hollow]

yeah it's strange that it randomly happens 😄

[winged veldt]

tbh i'd like it to be generally usable later, but right now it's super wip so 🤷‍♂️

[old hollow]

yeah hehe

I like it anyway

I've gotta do a similar thing but in rust, just as a way to learn rust and wgsl which is very unique compared to glsl or hlsl

glsl to hlsl and reverse is easy to transition, but going from hlsl / glsl to wgsl is really weird because it's completely unique 😄

[winged veldt]

my first path tracer was in rust

it's kinda shit, just following along with rtow but it was super fun

[old hollow]

heh

[winged veldt]

ngl i miss rust lol

[old hollow]

😄 rust is pretty nice

I've had tons of people at uni saying oh learn rust

so I started 😄

[dense jacinth]

c++ supremacy

[winged veldt]

i'm one of those people lol i'm a rust evangelist at uni

(then i write c++ for most of my shit lol)

[old hollow]

haha 😄

[old hollow]

my uni module leader for adv programming (C++ module) hates rust

[winged veldt]

but yeah i think i prefer c++ for gp, anything else i like rust better, just very nice to write

though, gib polonius pls

[old hollow]

meanwhile, laughs in thread safe, memory safe

tbh c++ is ok it's just hard to figure out having never used it

did you do your rust raytracing on the gpu btw?

wgpu W

[winged veldt]

nope, cpu

this is my first gpu path tracer

[old hollow]

I'm legit hopeful about doing the path tracing stuff, and ohhh was it multi threaded ? and ah yeah. Ithink you did say that in this thread somewhere woops

😄

[dense jacinth]

we had Rust in our operating systems and security class

but only as a discussion topic on how to easily eliminate memory safety issues

[old hollow]

heh, we've got it next year in some multithreading module along with C++ and cuda

heh

also

linux on mac runs on rust

(asahi)

[dense jacinth]

ye, well parts of it

[old hollow]

yeah ofc

it's cool though

[dense jacinth]

i think its only some drivers

[dense jacinth]

well I had my first CS exam today about basic C programming, arrays, lists, queues and such stuff so that is still far away for me

[winged veldt]

bro showing up at uni with a smurf account

[dense jacinth]

kinda

[winged veldt]

on a totally unrelated note, @quick zealot i was thinking last night and i think i came up with a way to do gmon with slightly less insane memory usage

still needs one framebuffer per bucket, but at least it's not two per bucket

but basically instead of each bucket getting two pingpong buffers, each bucket gets one accumulator buffer and you have one single buffer you bounce off

anyway ima try to implement it soon™ when i finish setting up my post processing pipeloin

[old hollow]

Cool idea 😅

[timid frigate]

@winged veldt ???

[winged veldt]

gotta add it to the tonemapper list

added a proper post processing pipeline with arbitrary number of passes (tonemapping pass is always on and at the end), rn i only have the exposure pass so i did this thing to test

[timid frigate]

Me too to my renderer

[winged veldt]

but it should be pretty shrimple to add more post processing passes now

[timid frigate]

And autoexpo

[old hollow]

Nice hehe

Exr output when

Or does that work already heh

[winged veldt]

no

[old hollow]

😅

How dare

[winged veldt]

actually exr output is pretty trivial

[old hollow]

Yeah haha

[winged veldt]

i just export the pre tonemap framebuffer

[old hollow]

Yeah heh

[winged veldt]

hdr display otoh is uhh

i mean i want to do that at some point

just not now

[old hollow]

Yeah I mean Macs are all hdr hehe

M series anyway idk about air models but I’m guessing those too

HDR on Mac is amazing tbh

[winged veldt]

ye, works great

i have to figure out how to actually use it, though

and more importantly deal with imgui

that's probably gonna be the hard part

[timid frigate]

I do. with and w/o tonemapping

[quick zealot]

why two per bucket? I've been using one since the beginning 🤔
Why ping ponging ?

What I do is I have one framebuffer per bucket yeah
So 5 framebuffers if 5 buckets

And

sample 1 is accumulated in buffer 1
sample 2 is accumulated in buffer 2
...
sample 6 is accumulated in buffer 1

[winged veldt]

ah wait you read and write to the same buffer?

[quick zealot]

Yeah, I only need to read when I do compute the GMoN stuff

otherwise, it's just accumulation

[quick zealot]

(every M samples i.e. when each bucket gets 1 sample)

[winged veldt]

accumulation is r+w tho innit

[quick zealot]

oh yeah true

lol

[winged veldt]

huh

[quick zealot]

so yeah I read/write to the same buffer indeed

[winged veldt]

wait you can do r/w to the same buffer

why didn't i think of that lol

[quick zealot]

VRAM 🔥

[winged veldt]

am i stupid actually

huh iirc the apple rt example used two accumulation buffers

wonder if there's some berf reason

[winged veldt]

tbf one extra framebuffer ain't much

one per bucket tho

[winged veldt]

ima try this when i get back home

[quick zealot]

why two?
like read from the first
sum to the value read
write the summed value to the second?

[quick zealot]

[winged veldt]

ye

[quick zealot]

[winged veldt]

[quick zealot]

not sure why you would do that yeah

perf sounds like a bit of a stretch but idk

[winged veldt]

yeah uh

actually idk

[quick zealot]

maybe the rt sample is just poop

[winged veldt]

ig i just assumed the apple example did it for a good reason lol

and then just left it there

[winged veldt]

maybe

[quick zealot]

or simplistic for "sample purposes"

[winged veldt]

apple skill issue

[winged veldt]

it's literally easier to writr to the same buffer tho

[quick zealot]

true

[winged veldt]

oh wait

i think i know why

compute+raster parallel

so while you're accumulating on buffer a buffer b is being drawn to the screen

or sth like that

[quick zealot]

oh I see that would make sense

but huh

that doesn't prevent race conditions though does it? if displaying and rendering are truly asynchronous, this doesn't prevent from the compute writing to the buffer being displayed
you'd still need some barrier somewhere
and if you have a barrier, things are not asynchronous anymore and so you don't need the two buffers anymore?

are they buffers or textures?

[winged veldt]

textures

[quick zealot]

textures can be read+write?

[winged veldt]

idk actually

i'll have to try

[winged veldt]

turns out they can

so uh

there's no reason to bounce two framebuffers for rt

basically i am stupid

[winged veldt]

a little bit of color grading can go a long way, this is just simple lift/gamma/gain after tonemapping

[winged veldt]

got the shadow/highlight "zone" exposure working a bit better, it's actually pretty usable now, also added vignetting

also wow that's a lot of fireflies, i should deal with that lol

[winged veldt]

@quick zealot how are you sorting your buckets for gmon?

i assume you're doing it on the gpu in a compute shader

[winged veldt]

fireflies are being dealt with

unfortunately gmon also seems to get rid of a lot of indirect light along with the fireflies

i'm gonna try tweaking some parameters to see if i can improve it, but i might go looking for alternative means to remove fireflies because the donwsides are pretty big

[winged veldt]

i had a bug, looks much better now though it still has some issues

[winged veldt]

fixed, turns out 11 buckets is just way too low to get good image quality out of it

ofc more buckets -> better quality, though oddly enough at 25 buckets the best results seem to be when clamping the gini function result to 0.25 so it's not overly aggressive

15 seems to be the sweet spot for image quality vs memory use (which is significant, given every bucket is an additional framebuffer)

[winged veldt]

some nice renders

anyway now the fireflies are taken care of, i think i'm gonna do a quick round of refactors/cleaning up the code and then finally work on replacing the placeholder sampler with something better

[dense jacinth]

man this is motivating me to get back into rendering

what hardware you running?

[winged veldt]

m3 pro, base 11 core model

so the gpu is 14 core iirc

[dense jacinth]

ah so exactly the same

what render times are you seeing here?

[winged veldt]

honestly it's plenty fast

[dense jacinth]

cause i do have a 3060 ti which would probably be more performant, so thinking wether to use vk or mtl

[winged veldt]

those two renders are massively oversampled, 4k and 1k samples for the left/right one

left took ~6 min, right about 2 min both at 1920x1280

[dense jacinth]

ah ok so its just more orless bruteforce right now?

[winged veldt]

mis+nee, usually i'd be rendering at 200-500 samples but these have a lot of indirect lighting, really these are scenes i should be using bdpt or similar on

and i haven't done much to optimize perf

for example it's all one megakernel, idk how much faster it would be if i was doing wavefront (i intend to switch at some point)

[dense jacinth]

tbf I could probably slap a raytracer ontop of my previous attempts at a gltf renderer, since that's written in a really modular and nice way tbh

[winged veldt]

3060ti is probably gonna be faster, but the m3 pro has the vram advantage because all your ram can be used as vram, so there's that

[dense jacinth]

well yeah it's a lot simpler

I mean with my renderer setup I could also have it run on both apis at the same time, with a dedicated renderer for each but with shared shaders

see whats quicker

though yes hdr + p3 might be a big plus

idk time to think about this stuff after I write this exam which I am totally not procrastinating learning for right now

[winged veldt]

can you do shared shaders between metal and vk with rt apis?

[dense jacinth]

idk tbh, probably not since spirv-cross doesn't support it

what I do is I abuse macros to their fullest extent to have a single header compile as GLSL but also as Metal

and then I'd put stuff like the BRDF or other functions like that into those headers

and then the Metal or VK specific shaders just call the functions from those headers

well in theory at least, in my project I only focused on the Metal impl so most of the stuff is metal specific code, still

https://github.com/spnda/vk_gltf_viewer/blob/renderer_interface/shaders/resource_table.h

definitlely not easy to read, I'll be honest

but that's one of the worse examples

[quick zealot]

yeah it's on the GPU, each thread sorts its M means with a single threaded radix sort

[quick zealot]

Can you send the scene for this one? I think I'm seeing a different behavior when cranking the number of sets up

I've found that with more sets, my denoising/darkening/bias is stronger and more samples are needed to get an acceptable bias level

but your images here show the opposite? (if they are equal sample count)

[winged veldt]

oh

[winged veldt]

yea, these are all 1024spp

i expect fewer buckets will work better with fewer samples

but gmon really does not like sample counts under 100 or so

[old hollow]

Even on my non-hw accel M1 Pro it’s fucking fast 🥰🥰

[winged veldt]

oh neat, i don't think i asked what kinda render times you're seeing

@quick zealot here's the scene btw

should be the same as the one i'm using, don't think i modified this one in editor

[old hollow]

You did I just forgot to say

Btw how are you able to do sun lighting. I didn’t see an option I don’t think in the editor 🙂

[winged veldt]

it's just the hdri

[winged veldt]

@quick zealot you have gltfs for the white room scene and the other similar ones?

i've only found blender files but the exporter shits itself

[winged veldt]

got distracted with this, found a nice model of the main hall of the london natural history museum, had to do quite a bit of cleaning it up in blender but it looks pretty nice just lit by sunlight

no textures unfortunately, i might have a go at adding them later at some point

[bronze sedge]

what did you have to clean up?

[winged veldt]

(i also removed the glass for this render, i don't have transparent shadows or anything so nee wouldn't work with it)

[winged veldt]

the original model is only half, so i had to duplicate and flip it, also cleaned up a lot of poorly placed sharp edges that made the columns look not-round

then i merged the whole thing because blender can't export a gltf with transforms if its life depended on it and had to spend a while fixing flipped normals from the parts that were flipped with a negative scale

cleaned up nicely though, and the model is great—actually made by hand with good (if a little low poly) topology, most of the architectural stuff you find on sketchfab is 3d scans which are kinda useless for rendering

and the detail is fine if you don't look too close

at least all those scans of the place will come in super handy if i decide to texture the thing

[bronze sedge]

ah

[bronze sedge]

I have to fix models inside blender too, like add tangents or fix the textures. Was wondering what this involved for you. Thank you

[winged veldt]

i add the tangents in engine (mikktspace) specifically because blender doesn't export them properly half the time lmao

i will never get tired of shitting on the gltf exporter

[bronze sedge]

I'm going to try and add an fbx importer to my engine

I haven't added mikktspace as I'm just not enabled for any kind of mesh optimization at the moment, I honestly don't even know how, like how to fix all the index counts and starts on all the primitives after mesh optimization

[winged veldt]

i'm not actually using it properly atm but i choose to ignore that for the time being

about fbx uh, good luck

[timid frigate]

Which fbx lib you plan to ise?

[bronze sedge]

the fbx sdk I think

I don't know anything about it yet :<

[quick zealot]

So in order: OFF, 5, 7, 11, 15, 17, 25
1024SPP

Actually on this scene there is basically no difference because the variance isn't too bad
Your indirect being quite a bit darker is a bit sus I would say on the front face of the dragon
There are no fireflies there so why is GMoN murdering that spot?

There is a bit of darkening between OFF and 25 which I guess is what I wanted to see initially

[timid frigate]

seems https://github.com/nem0/OpenFBX is good and popular

[timid frigate]

and maybe https://github.com/ufbx/ufbx not bad

about fbx libs need to be tested both approaches

[quick zealot]

But it's way more pronounced on Sponza where the variance is worse:
OFF, 5, 7, 11, 15, 25
512 SPP

[quick zealot]

Ok let me cook

[bronze sedge]

Thank you will take a look

[quick zealot]

Those are pretty much all the good scenes I have right now: https://mega.nz/file/s4BCARRZ#P_mEpVjimxLYojhc6aiZbEsCzcT2MPxguXg8cI5m0bw

3 the white room versions:

• lucy is the one I used for the screenshot above (although the material was edited at runtime)
• lights is the one with many lights for stress-testing NEE
• low is the one with more lights than lights (naming doesn't really make sense here hehe)
• the-white-room with no suffix is the "easy" one, classic

[quick zealot]

by "clamping to 0.25" you mean their "Binary GMoN" approach?

[timid frigate]

my tune ups of lucy material

[old hollow]

btw this is a video showing the bug on my mac, NEE + MIS sometimes works, or it does this

that's with the entire scene material emissive

and then

with simple

so I think there's deffo a bug to fix 😄

[winged veldt]

hm, your gmon off image looks way better than mine, though

maybe it's my crap sampler? i'm working on replacing it so we'll find out soon ig

or maybe it's time to refactor my bsdf code again

[winged veldt]

that looks pretty much like what i'd expect, only i'm getting better results with higher bucket counts but that's likely because i'm rendering at higher sample count

also that looks super clean for 512spp tbh

[winged veldt]

thanks, btw where'd you get the scene? did you manually export from blender?

[quick zealot]

the white room?

[winged veldt]

ye

[quick zealot]

hmmm well I'm still on pure pseudo random uncorellated white noise shit sooo

[winged veldt]

oh btw my specular highlights on the dragons scene aren't nearly bright enough so yea, bsdf rewrite time

[winged veldt]

damn

[quick zealot]

I think I got it on blendswap
But I did tweak it a bit here and there iirc

[winged veldt]

how's it look so clean? is that just plain mis+nee?

[winged veldt]

ah ye
i got it from blendswap but i'd have to redo all the materials

[quick zealot]

oh maybe I did do that yeah, don't remember
but yeah the GLTF exporter is poo poo garbage, it basically only exports the principled BSDF

[quick zealot]

This mayyy be because my GLTF is ASSIMP
And ASSIMP is ass at reading GLTF
So I strongly assume that it's not reading the specular correctly (may be wrong though but eh, I've seen that before with ASSIMP)

[winged veldt]

eh? there's no specular, only a roughness param

[quick zealot]

That's RIS actually
1 BSDF sample + 4 light samples resampling

[winged veldt]

ohh

well that explains why it's so clean

dammit

[quick zealot]

Wait I'm bsing then xD
Let me check

[winged veldt]

honestly i think that's fine lol
i'm trying to figure out wtf the code from a paper (z sampler) is doing and not having a good time of it

ngl, i fucking hate pbrt

the code is so ass

book is fine, though

[quick zealot]

One thing that kind of worries me with LDS is that you have to be careful to not break the stratification so you have to count your samples and rescale them sometimes blah blah blah

Whereas with my good old Xorshift32, you just ask for a float [0, 1] and tadaaaaa

[winged veldt]

yeah it's definitely more complicated

but it does look much better at low sample counts, so worth it

it's also just really interesting, mathematically

[quick zealot]

ye I agree, maybe I'll have a go at some sobol stuff someday

it's still good, being that it is basically multiplicative variance reduction with all the rest

[winged veldt]

yea, it does converge faster

rn i have a crappy halton sampler which is fine for convergence but just really crap code lol

so i want to solve sampling for good

then i can uh

go back to fixing my layered bsdf

[quick zealot]

Those are the mats loaded
look okay

[quick zealot]

what's roughness 0 if it's not smooth specular though ? 🤔

[winged veldt]

ye, that's basically what it should look like

[quick zealot]

then it's all okay I guess, disregard the ASSIMP rant hehe

[winged veldt]

yea i mean there's no "specular" parameter as you'd have in some non-pbr material

well technically gltf does have specular intensity/tint but i ignore it

[quick zealot]

oh ye okay

[quick zealot]

although wait, I don't do RIS on the envmap, only on the emissives
and sponza is envmap only
so yeah it's pure MIS

maybe that's because I have the full BSDF evaluation instead of just the sampled lobe

[winged veldt]

might be

but also yeah taking a closer look the noise seems about right

also those trees might be scattering some light into the hallways to the side?

[quick zealot]

doesn't look like it

[timid frigate]

maybe pcg4d is better?

[quick zealot]

what is it?

[timid frigate]

http://www.jcgt.org/published/0009/03/02/

pcg4d is lds
implemented here
https://www.shadertoy.com/view/XlGcRh

[timid frigate]

with initRNG is here https://github.com/knightcrawler25/GLSL-PathTracer/blob/291c1fdc3f97b2a2602c946b41cecca9c3092af7/src/shaders/common/globals.glsl#L155

here is interesting approach with blue noise https://www.shadertoy.com/view/wltcRS

[quick zealot]

is it LDS though?

looks like it's just uncorrelated white noise no?

same as my xorshift

[timid frigate]

100% lds https://www.pcg-random.org/index.html

[quick zealot]

🤔

[winged veldt]

i thought pcg was white noise?

afaik it's just a regular prng with a uniform distribution

[timid frigate]

yes

[winged veldt]

so not a lds then

[timid frigate]

pcg4d is better than xorshift

[winged veldt]

this seems incredibly simple, does it work for higher dimensions?

[timid frigate]

@winged veldt please read pdf. lds is better

[timid frigate]

yes. I mean rng

[winged veldt]

no mention of low discrepancy sequences there

yeah, pcg is state of the art prng afaik

at least for fast ones

[timid frigate]

xorshift is worse vs pcg4d

[winged veldt]

yes you have said this already

getting somewhere with the new sampler, it works properly now for 1spp