#StratusGFX - Realtime Rendering Engine

1233 messages · Page 2 of 2 (latest)

worldly inlet
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Trying to find the fix

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Also let me update that one chart to say 4 bytes

grave kettle
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Yeah I have an array of pages instead of a big 2D texture at the moment

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But I'll have to use a big atlas at some point because I'm only guaranteed 2048 array layers

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I think I'll still keep the 1D addressing scheme in the future though

worldly inlet
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Oh that’s right I forgot about that

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So 1d but it can still work? Will you have to pack multiple things into it or just single address still?

grave kettle
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Well it'll be a 1D address but I'll just expand it to 2D by reading the image size

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I'll have it behind a function so it looks 1D to the user hehe

modest flicker
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me when / and %

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it's page size btw, do not conchfuse like last time

grave kettle
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I'll need to simplify my API as much as possible if even I'm to understand it bleakekw

grave kettle
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Divided by the page size of course

modest flicker
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uhh yes

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I think

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I use a stupid simple addressing method in my partially working sample

grave kettle
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I'll just ask chadgpt

modest flicker
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which is take pixel, divide by page size, now you got page index

worldly inlet
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I think that works

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Wait…..

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Yes

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I think vsms gave me brain failure

modest flicker
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it's a global brain failure

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our shared neuron is in grave danger

fossil thicket
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i read it all

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: ) and i would not be able to implement it myself as is. im simply too dumb for it after work

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but

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i reads very nicely

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and although i barely understand anything i enjoyed reading it for some reason

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the pics help too

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what i did understand, conceptually is the analogy to virtual/physical-isms

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that makes sense

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and im glad you are here 🙂

worldly inlet
worldly inlet
fossil thicket
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i hope i will be able to implement that cool stuff too : >

worldly inlet
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Join us in the vsm trenches lol

fossil thicket
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i will watch from the sky and see how it pans out first XD

ornate aspen
grave kettle
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there are some comparison pics

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oh wait nvm I thought you were talking about the UE5 docs KEKW

worldly inlet
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Oh yeah good point

grave kettle
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yeah this super complicated technique needs some motivation lol

worldly inlet
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“Why do you want to be miserable for this? Here’s why”

worthy thorn
grave kettle
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hey man please troll people in #off-topic-🐸 or #bikeshed-😇

worthy thorn
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but hey, ue5 docs can be interesting too, i guess

worldly inlet
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Hmmm I could add in some comparison pics with CSM at different resolutions

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Maybe briefly talk about other approaches (tho I don’t have them implemented locally)

grave kettle
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btw I noticed in your reddit post that you have a gtx 1060

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the UE5 VSM impl was probably not designed for that class of hardware sadly

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regardless, have you tested it in UE5 to see how the perf is?

worldly inlet
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Oh actually no I haven’t

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I’ll need to figure out how to test it - I’ve only used UE4 so far. Do you know of any vsm test scenes they released?

grave kettle
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hmm I'd test by just loading a random scene and doing stat gpu

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I guess ideally you'd test with the bistro model, since that's what you're using already

worthy thorn
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but sure, the bistro model is a popular choice for testing graphics performance in ue5

worldly inlet
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though something seems a bit off though since sometimes the shadows disappear

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Enabled page visual and the regions the shadows are missing should be covered so idk what's happening

worldly inlet
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Added a small wip motivation/comparison section

grave kettle
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there's a typo in the article: nunmber

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btw UE5 docs recommend quantizing light rotations when you have a constantly rotating directional light so that the vsm can be fully updated over several frames before the next rotation increment

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also the gifs have an interesting blue-and-yellow check pattern and I'm not sure if that's intentional or an artifact of compression 😄

worldly inlet
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Dang yeah I’m not doing that currently but that’s a great idea

worldly inlet
grave kettle
worldly inlet
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Oh so it’s more of a guideline rather than an engine feature. That makes sense though. Tiny rotations constantly seem to be the worst case scenario for this

grave kettle
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Yeah there's a heap of useful tips on the ue5 doc for vsms

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Plus lots of info that hints at the underlying implementation

worldly inlet
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couple of changes to the article today:

  • Added a section talking about hardware/API sparse vs software (also made software sparse the default in my code)
  • Mentioned splitting light rotation into several steps instead of doing continuous rotation
  • Tried to make virtual mem -> physical mem section a little clearer
grave kettle
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What software do you use to make the graphics btw? They look clean

worldly inlet
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you mean the gifs? I export them as mp4 from davinci resolve then I convert to gif using this site: https://convertio.co
great site if the mp4s are less than 100mb

Convertio — File Converter

Convertio - Easy tool to convert files online. More than 309 different document, image, spreadsheet, ebook, archive, presentation, audio and video formats supported.

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also been thinking about how the software sparse would work in vulkan or DX... like from lvstri's experiments we know the sparse api is still super broken at least on windows
so maybe it would be something like allocating small 2D textures (1024x1024, 2048x2048) where the memory comes from a custom allocator as needed and freeing them whenever no pages were being used from them?

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1024 would give you 64 pages, but it would require a readback whenever a new texture block was needed

modest flicker
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yes you make an r32ui texture that has a reasonable size (i.e 256MB) and this is your physical memory

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I still think I'll just do readback for now

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maybe Jaker will convince me to switch

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But readback is blazing fast, it takes zero time to copy a few megs

worldly inlet
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I wonder if they’ll ever allow compute shaders to allocate memory

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But yeah read back is pretty fast especially if you just queue it up and then check the results next frame

grave kettle
worldly inlet
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Oh lol

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PowerPoint froge

grave kettle
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Epic

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I'm partial to paint.net myself but it's not good for vector graphics lol

worldly inlet
fossil thicket
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InkScape

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ugly af but can do vector giraffics

worldly inlet
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Edit: will repost when I have more info and maybe a demo

worldly inlet
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few more article changes:

  • comparison mentions other light types
  • page offset xy was changed to page index xy with slightly updated descriptions under the diagram
  • added a small allocator gif comparing hardware and software sparse
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updated gif to say allocator = pool

ornate aspen
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Tried compiling and running this, here's what I'm getting on AMD 6750 XT and Debian 12 thonk
(Running ./Ex00_StartupShutdown)

[Error] Thread::(Renderer) checkShaderError:50 -> [error] Unable to compile shader: viscull_lods.cs
0:226(61): error: parameter `in offset' must be a constant expression
0:226(19): error: type mismatch
0:226(19): error: operands to arithmetic operators must be numeric
0:226(19): error: operands to arithmetic operators must be numeric
0:226(9): error: no matching function for call to `normalize(error)'; candidates are:
0:226(9): error:    float normalize(float)
0:226(9): error:    vec2 normalize(vec2)
0:226(9): error:    vec3 normalize(vec3)
0:226(9): error:    vec4 normalize(vec4)
0:226(9): error:    double normalize(double)
0:226(9): error:    dvec2 normalize(dvec2)
0:226(9): error:    dvec3 normalize(dvec3)
0:226(9): error:    dvec4 normalize(dvec4)
0:226(2): error: could not implicitly convert return value to vec3, in function `sampleNormalWithOffset'

[Info] Thread::(Renderer) Compile_:226 -> Loading shader: ../Source/Shaders/viscull_csms.cs
==Begin Shader Source==
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It complains about textureLodOffset mainly thonk

grave kettle
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The*Offset sampling functions are really lame 😦

ornate aspen
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I encountered this too previously, idk why it’s that way - spec doesn’t say that it should be constexpr

grave kettle
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It does

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The offset value must be a constant expression

ornate aspen
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Oh, I see frOK

grave kettle
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I think some shader compilers differ in what they think a constant expression is

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It seems like some will inline the code before checking (which causes it to succeed), while others strip the context from parameters (so it fails to compile)

ornate aspen
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It’s sad that glsl doesn’t have constexpr guarantees/constructs that C++ has

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Wouldn’t be a problem if it was just for optimization (like inlining), but when it requires you to be constexpr, but doesn’t give you the tools - that’s frustrating.

worldly inlet
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Yeah maybe it’s something like that, dang. Once I’m at the computer I’ll do some digging for a fix

worldly inlet
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"The offset is supposed to be a compile-time constant. If you pass value obtained from a constant array by index, the code will normally work only if the loop can be unrolled, so that the individual texelFetchOffset calls end up with constants for the offsets.

On Nvidia it usually works, but AMD drivers often do not unroll the loops, perhaps because of more efficient loop implementation. In that case the offset expression is not constant anymore, and loops with texelFetchOffset fail to compile or link."

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this is probably the same issue

grave kettle
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GLSL is painfully underspec'd

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"yeah things can be constexpr if the compiler wants to do it"

worldly inlet
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D:

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I'm guessing this has been cleared up with SPIRV in vk (the underspecced part)

grave kettle
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at least there is basically one canonical spir-v compiler

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and it's open-source

worldly inlet
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yeah that's actually amazing

grave kettle
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so you can open issues if it does stupid stuff

worldly inlet
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and DX12 also open sourced theirs and can deal with SPIRV

grave kettle
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ye tbh though just use DXC and write HLSL since it's 100x better than GLSL

worldly inlet
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yeah that sounds kind of interesting actually

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HLSL -> SPIRV -> vulkan

grave kettle
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yeah lots of people do it

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GLSL is practically in maintenance mode while HLSL is getting more C++ features all the time

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however, I'm not sure if HLSL can deal with BDA yet which would be one good reason to avoid it

worldly inlet
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oh no, wonder if there are plans to add that

grave kettle
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I think they are currently bikeshedding pointer design and gob doesn't like what they're coming up with

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or something

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through gob and devsh, I get the impression that the designers of HLSL are missing something

worldly inlet
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I'm not caught up there but I've seen some of his posts about the compiler stuff he's doing

modest flicker
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you need to do some funky SPIRV intrinsics everytime you wanna use an extension that's not supported

grave kettle
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the shading lang situation is pathetic atm but HLSL seems passable for "serious" projects

modest flicker
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and by "funky" I mean really funky

worldly inlet
grave kettle
modest flicker
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I'm talking writing opcode IDs

worldly inlet
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oh no lmao

grave kettle
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that's so much better than simply not being able to express it though

modest flicker
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yeah true

grave kettle
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how painful is BDA by spamming spirv opcodes

modest flicker
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I have no idea KEKW

grave kettle
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I'm sure you could wrap it in a class template that makes it a little less sucky

worldly inlet
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does that mean he writes HLSL and manually injects opcodes to enable bda?

grave kettle
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wdym manually

modest flicker
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you can do vk::RawBufferLoad right now I think

worldly inlet
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idk, maybe like during compile time

modest flicker
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but it's garbage because [insert devsh reasoning]

worldly inlet
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(I haven't looked at it KEKW (

grave kettle
modest flicker
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ye KEKW

worldly inlet
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oh that's actually a lot better than I was thinking

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not great but better

fossil thicket
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IF i have to use hlsl for reasons

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id like to write hlsl like a sane person

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without special attributes or opcodes here and there

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just like in good old d3d11 days : )

worldly inlet
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the future is now and it's spirv::4213728

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no i agree wish it were better

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maybe someday the shader langs will be sane again

fossil thicket
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or at least, let devsh coerce mirkosoft people into make a better hlsl where shit is built in

worldly inlet
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let me know if anything changes! i don't have any amd hardware to test on

ornate aspen
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Capturing it with nsight just crashed my X11 froge_bleak

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Warehouse sample is 100+ FPS, though

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My PC sounds like a jet when running the "bathroom" demo 😄

worldly inlet
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Oh wow the sponza one is definitely odd

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Does it stay at 30 even if you let it run for a bit?

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Though the 6750 is probably a really good card. I did all the testing on a potato gpu and it can get 45 or so on sponza

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Jaker is there a way that an amd perf capture can be run and debugged on a pc with an nvidia card?

grave kettle
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you don't need an AMD driver to open an RGP trace

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you just need RGP

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oh wait this is OpenGL, RGP doesn't work with that froge_bleak

ornate aspen
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I’ll try running nsight on Windows later, it shouldn’t crash 😂

obtuse dagger
obtuse dagger
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Inline SPIR-V is great

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It's actually the only sane way to get this stuff in HLSL

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The other alternative is getting the SpiR-V extensions after 3 years when they're no longer shiny

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And also if and when the HLSL Devs feel like giving them to you

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C.f. the BDA fiasco

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With proposal 0011 you can define new types and built-in variables properly

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Meaning you can expose any new SpiR-V Khronos ratifies as an extension

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As a HLSL type, function etc

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Without having to go deep into HLSL compiler internals and applying your own patches and then having them refuse support cause you basically have your own fork

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The only glaring hole in proposal 0011 is that the type definition is missing a lot of ahit

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Please support my comment

grave kettle
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May I offer you a 👍 in these trying times

fossil thicket
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im also not sure what you mean with arrogance

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i meant it in the best way possible, support you

obtuse dagger
grave kettle
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if this doesn't go through, it will be our own personal 9/11

image.png
fossil thicket
obtuse dagger
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there is no other way to be forward compatible other than SPIR-V intrinsics

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and writing out opcodes and function signatures

fossil thicket
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thats ok for me

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i know you try to help the cause and I admire that, although I do not understand 90% of it

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das all 🙂

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at least im slowly abandoning opengl already

obtuse dagger
worldly inlet
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Guess that means it’s time to switch to hlsl

worldly inlet
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haven't worked on this too much lately, but I made some progress with the VSM scheduling system recently. The issue I would run into is that sometimes a lot of changes happen quickly such as with a major camera movement. The perf would fall a lot more than normal leading to frame time spikes

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new system sets up a budget per clipmap with a CPU scheduler. Now if huge numbers of update requests come in it allows itself to fall multiple frames behind and uses coarse data as backup

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also uses new hpb for culling which gave some solid improvements

grave kettle
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hpb froge_love

worldly inlet
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yeah froge_love

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really happy with hpb

worldly inlet
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but now when the camera starts going nuts the frame rate stays pretty high

fossil thicket
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@worldly inlet are you still alive?

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sheesh, its been 2 years, almost

worldly inlet
fossil thicket
worldly inlet
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lately I've shifted to game dev froge_love

fossil thicket
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i remember that, looks like potrick inspired probeisms 🙂

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everyone is abandoning opengoodluck

worldly inlet
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Yeah I jumped in on the probe bandwagon for a little while. I really like the results they give even without RT

worldly inlet
fossil thicket
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not yet

fossil thicket
grave kettle
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I'm probing it up as well except I'm using rt to populate them

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but that's mainly because rt is the only way to render voxels in my engine atm

worldly inlet
worldly inlet
# fossil thicket not yet

it's kind of a pain until you get some nice abstractions up and running
or until you borrow someone else's lol

grave kettle
worldly inlet
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Oh it's in frogfood?? I must have confused myself, I was looking for the other thread

grave kettle
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a bit confusing innit

worldly inlet
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must be tuesday again

main pagoda
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I hate tuesdays

grave kettle