What is the best way to solve this shader graph issue?

[brave tapir]

maximum ps_5_0 sampler register index (16) exceeded
I have read that its maybe because of the target platform supports Shader Model 5.0, and the max Texture sampler number is 16, and if there are more Texture Sampler nodes are in the shader graph than 16, then the error will appear.
Is there a way to solve this without remaking the shader graph?
Can I make preprocessor directive-like nodes into the shader graph?

[brave tapir]

as I read, maybe the best solution is to create 1 Sampler State Node and connect that to all of the Sample Texture node's Sampler input, and that's all?

[rigid spoke]

Yes, that might work. Though obviously all the texture will have to share the sampler state.

[marsh pelican]

you dont have to connect them all to the same node, you can create separate nodes, the graph is smart enough to figure out which textures share the same sampler settings

[tall frost]

and is it normal that the shader graph compiles for 14 hours now (only this one)? I selected the shader graph and I'm compiling only for build platform

and its not freezed out, its still ongoing

@rigid spoke

[marsh pelican]

haha wow, you need to remove some shader keywords

[tall frost]

how? if its a shader graph

[marsh pelican]

you added shader keywords yourself, did you not?

[tall frost]

well, its a shader graph written by others million years ago

[marsh pelican]

well, maybe you want to take a look at it anyway

[tall frost]

so there might be keywords, I have no idea

I mean I'm not pro at shaders, I'm mainly a gameplay programmer

[marsh pelican]

like, specify which shader stage(s) they are needed, and check shader feature vs. multi-compile depending on if you activate them through code or not

[tall frost]

so can you help me what to look for?

[marsh pelican]

yeah, you'll need to open it and look for parameters of the type "enum keyword" and/or "keyword"

[tall frost]

so should I cancel it?

[marsh pelican]

well, at that rate I guess it will go for another 42 hours..

so probably

[tall frost]

@marsh pelican okay, so I cancelled the compilation.
How to open it?

where should I find the "keyword" part?

[marsh pelican]

look for the shader graph in your project, I don't know it's name but i expect it's something like TerrainIce ?

you can filter by shader graph with t:ShaderGraph

[tall frost]

these are the keywords

[marsh pelican]

you need to open it

do you have knowledge about what kinds of features you need from this shader, in your project?

[tall frost]

I have zero knowledge about it

absolutely zero

[tall frost]

pretty huge shader graph

[marsh pelican]

what a joy to look at 🙈

[tall frost]

so as someone with zero shader experience, what should I do with this?

[marsh pelican]

it's not very different from regular programming, except that this is code that is executed for every vertex or pixel

[tall frost]

I know that part

I know its probably a vertex and fragment shader

[marsh pelican]

right, so you need to try and look at the keywords and see what code is activated/deactived by them

[tall frost]

but my knowledge is almost ends here

[marsh pelican]

and see if you can identify keywords that have very little attached to them

those you can replace by a regular branch instead of a shader keyword branch

[tall frost]

and how to open the code?

[marsh pelican]

this is the code

[tall frost]

I thought you mean the generated code

[marsh pelican]

well, you can look at that, but that's much harder to read

do you have a lot of materials that use this shader?

and are you working alone on this or are there others that know more about this shader?

[tall frost]

no idea. I only know about one thing which is using this shader

[marsh pelican]

well, you need to figure this out, to be able to make changes you need to be able to update the materials that use the parameters

[tall frost]

there's one, but he's assigned to other stuff

[marsh pelican]

and you need to find out if there are places in the code where you set shader keywords on materials using this shader

you can see if a keyword can be overridden with a global keyword, if the Is Overridable option is checked

[tall frost]

so where should these keywords be in the shader graph?

as node names?

or what?

[marsh pelican]

they are inputs, like regular material parameters

you can see the type of input parameter next to the name

well, they're called Properties, officially

[tall frost]

well, in the left side I can see lot of input parameters like SnowDirection, SnowIntensity, etc., but these are not appearing on the right side

[marsh pelican]

if you hover over them, it will highlight any nodes in the graph that are linked to the input

the keyword boolean and keyword enums are the ones you are interested in

I also recommend you make a backup of the graph (and the materials, if that's feasible), that way you can relatively easily go back if things go wrong

(and compare)

[tall frost]

well, we use version control

[marsh pelican]

yeah, but even then, you will want to be able to compare them

[tall frost]

but those are not here in this list

oh never mind

they are here

some of them

[marsh pelican]

its possible some of them may exist only in the custom hlsl nodes

a lot of them are added by unity

[tall frost]

I can only see 3 keywords appearing in the left side

and if I hover them, I can see them in the graph

so that means all other keywords are unnecessary?

[marsh pelican]

no, it just means your shader does not use them itself, but they can still be used by the render pipeline and such

shader graph adds them for you

during build, any unused shader variants are usually stripped and not compiled

you can also customize this stripping process if you know certain keywords are unnecessary

these ones, I guess you are using HDRP?

there is some information about shader stripping here
https://docs.unity3d.com/6000.2/Documentation/Manual/shader-variant-stripping.html
it also talks about keywords

[tall frost]

yes, HDRP is being used

[marsh pelican]

I fidn it surprisng you have 62 thousand shader variants and only added 3 keywords in the graph yourself

are they enum keywords?

[tall frost]

its _OTHERWORLD_MASK_ENABLED which is boolean

_TESSELLATION_ENABLED, also boolean

_MATERIAL_QUALITY (built-in enum)

[marsh pelican]

how many quality settings do you have in your project?

[tall frost]

5 pieces

[marsh pelican]

that's not a lot of keywords in the blackboard indeed

okay, I suppose you use them and that you need the material quality

[tall frost]

yeah, these 3 keywords are being used in the graph

and about the qualities, yeah, those 5 are used

at least 3 of them for sure

but maybe all 5

[marsh pelican]

in the HDRP asset you should be able to find the quality level in the material section and verify they (material quality settings) are all three in use (low, med, high)

I never used HDRP, but there's a page on reducing variants for HDRP specifically

https://docs.unity3d.com/Packages/com.unity.render-pipelines.high-definition@17.0/manual/reduce-shader-variants.html

[marsh pelican]

for this one, and the tesselation enabled one, you may want to check if they are shader features or multi-compile
also check if they enable/disable a lot of code

if its using shader feature, it will only compile the flag with the settings coming from your materials; if all materials use the same setting one, modifying this keyword will not do much for you

if its multi compile you need to see whether the keyword is set through code

otherwise you may be able to replace it by a regular branch

beyond this, i guess you would have to dig into the custom hlsl nodes, which may or may not be easier depending on the code

[tall frost]

so basically I should look for if our project is not using some of these

and those could be set to the suggested values here?

[marsh pelican]

indeed

that should help with all shader compilation times, not just this big one

[tall frost]

okay, thx. I'm not sure if anyone if the project would be able to answer which of these are being used

but I will try

the whole shader is more than a year old

probably 2-3 years old

[marsh pelican]

yeah you may have to dig a bit then, find references and all that

ah though for features that is a bit harder indeed

[tall frost]

@marsh pelican so if I look into the generated shader code

can't I just CTRL+F and search for the keywords one by one?

although if I would see a keyword not used in the generated shader anywhere, how could I remove that from the graph itself

[marsh pelican]

for this shader I think you first need to find all the custom HLSL nodes in the graph itself and see what code (and keywords) is added by them

[marsh pelican]

if a keyword is not used in the generated shader, I don't think it would be compiled for the graph either

the problem is keywords that do something, but are not actually used by anything in the game

or dont do something useful

[tall frost]

okay, so then why did you say to look for unused keywords?

if we can't do anything with it

[marsh pelican]

I don't think I said to look for unused keywords ? 🤔

[tall frost]

okay, maybe I misunderstood you then

[marsh pelican]

maybe, I may have phrased it poorly

unused features, maybe

[tall frost]

I got an info that maybe this shader is not even used anymore... 😄

[marsh pelican]

that should be possible to verify by traversing the references

but that would be great 😄

[marsh pelican]

it's still referenced by something though, otherwise it would not compile of course

[tall frost]

yeah

I tracked shaders with Project Settings

and it got found

[tall frost]

@marsh pelican can't I just set quality to low and disable all other qualities?

won't that speed up the compilation?

[marsh pelican]

I assume it will help yeah

but i figured you'd need them?

[tall frost]

I would, but for now I would just check everything else in the target platform

if other stuff works

I would honestly temporarily disable this whole shader

if I could

[marsh pelican]

if you just want to do it locally, you can always do find all references and change the shaders of the materials that use it
or simply delete it

[tall frost]

well, I could do it with this shader, but there's an another one, which is similarly bad

and that's being used by a lot of things

[marsh pelican]

well, I have to go unfortunately, but you have a lto more information now

so I think you can find a temporary solution at least

[tall frost]

are those "lot more information" in the same room with me?

[marsh pelican]

😆

if you just need to test you can open the shdaer graph and clear its contents 😄

[tall frost]

well, yeah, but I need to fix it primarily, or at least get it compiled in a bad quality

if it could got compiled in a worse quality, it would be enough for me for now

[marsh pelican]

I think you can remove all the other quality levels then

[tall frost]

already removed them

for target platform

[marsh pelican]

that didnt help?

[tall frost]

nope, still 62K variants

and still it was slow after 17k (the point it got compiled during 14 hours)

the weird is that this shader got compiled well for other platforms

I never had this issue before

with this shader

[marsh pelican]

strange, unfortunately I'm a little out of my depth here (and out of time)

[tall frost]

maybe because I added the Samplers?

okay, thx

this is the other one, even better

[tall frost]

@rigid spoke if I use shadervariants file (generated by tracking used shader variants), then for shader compilation, it would just received from that file?

[rigid spoke]

Not sure. What do the docs say?

Normally unity would strip variants that it decided would never be used. And compile any that might potentially be used. Based on different project settings.

https://docs.unity3d.com/6000.2/Documentation/Manual/shader-variant-stripping.html

[tall frost]

I don't really understand based on this about what should I do

[rigid spoke]

You'll need to be a bit more specific.

[tall frost]

it says: "Check what shader variants you have to help you see which shader variants and keyword combinations Materials need at runtime."

well, based on the link it writes

no information is provided

and no info about how to set to include only the necessary ones

[tall frost]

its very hard to ask, when I don't understand the whole thing

when I start to compile the other shader called Lit/Actor, it says I have 100K variants... for the TerrainIce it says 62K

are those all variants really needed based on the project?

[rigid spoke]

You don't really have direct control over that. Unity collects the used keywords based on project, rp, renderer, lighting and other settings and compiles all the possible combinations.

[tall frost]

are these the correct settings?

[rigid spoke]

Reducing the amount of quality setting tiers, disabling features in the render pipeline settings could help

[tall frost]

like this?

[rigid spoke]

There's not correct. It depends. And I've no clue what automatic does, or how it decides if to strip or not. Might need to look at the docs.

I'd start with these things that you can modify right away without introducing any breaking changes into the project

Another thing to consider is if the shader cache is used. Normally, only the first build should be heavy, while consequtive should skip shader compilation, unless there are new variants required.

[tall frost]

for other platforms even the first build didn't took for 10+ hours

only 2 hours

[rigid spoke]

Then it uses way less variants. Or you already had some shader cache

[tall frost]

and these 2 shaders were not changed in the last 2 years

nope, variant number is the same

I just checked it

the whole shader graph is the exact same, and if I comple those, I also get 100K and 62K variants for them

[rigid spoke]

How did you check that?

[tall frost]

I selected the shader graph in the other workspace and I clicked on compile and show code button

[rigid spoke]

That should only compile one variant I think.

[tall frost]

I didn't have shader cache 🙂 I cloned the project the same way

just selected a different target platform

that's all

[rigid spoke]

Or rather, it generates the shader code, not compiles the variants

[tall frost]

then why it tries to compile all variants?

but anyway... even if I created a build for the other platform for the first time, it took for 2 hours

not 10+ hours

even if we don't consider this "compile and show code" button

[rigid spoke]

When you click "generate and show code"?

[tall frost]

yeah

[rigid spoke]

Because it doesn't compile shaders

[rigid spoke]

It generates the shader code from nodes. Doesn't compile it.

[tall frost]

then what it does

okay

then how to compile shaders? only with creating build for target platform?

[rigid spoke]

Normally yes, because:

1. It uses platform specific compiler.
2. It uses platform specific configuration, keywords.

I think shader variant collections can be used to precompile them at will, but I don't know much about them

[tall frost]

it just literally says the name of the NDA platform

but okay then

still the first build took 10+ hours instead of 2 for the other platform

[rigid spoke]

Customizing these might actually help quite a lot. If you know what is used or not used in the project.

[tall frost]

so that's not normal it differs

[tall frost]

"If you know what is used or not used in the project."
yeah, I tried to figure it out in the past few hours, and I didn't receive too much info

[rigid spoke]

What was the other platform? If it was windows, it might have been using shaders compiled in the editor.

[tall frost]

nope. 2 different consoles.

NDA

both are NDA, but different NDA

[rigid spoke]

Well, then either they have a vastly different shader variant numbers, or the other platform shader compiler is fast fast, compared to this platform

Some platforms have several compilation passes too.

[tall frost]

I saw on the progressbar that it used the exact same amount of variant numbers

"or the other platform shader compiler is fast fast, compared to this platform" maybe that will be the case

[rigid spoke]

Then it's probably fast fast

Could be the compiler settings too. Some could be spawning several compilation processes or threads to make use of all your cores. Other might be configured to be single threaded... Really hard to tell without actually investigating it.🤷‍♂️

[tall frost]

could the enabled graphics debugging have something to do with slower shader compilation?

[rigid spoke]

Yes, quite likely, though can't say how much.

There's also the other side to it where compiler optimizations are enabled