Add Posterize option to LTCGI Diffuse #85

fundale · 2025-03-03T01:45:20Z

No description provided.

orels1 · 2025-03-04T20:30:08Z

Hmm, I'm not really sure I want to add a branch just for this 🤔
Especially in the LTCGI module that also gets used by world shaders.

The v2 of the toon shader (which is what I assume this is meant to be used with) could probably support an extra spot where you posterize the LTCGI results in its own module.

However, thinking about it some more it feels like doing something like using the Toon Ramp and other shading settings might be what you actually want? Then instead of just pure posterization with discrete steps - you could have full ramp-based control over how the diffuse shading from LTCGI is applied? 🤔

fundale · 2025-03-04T22:47:46Z

Hmm, I'm not really sure I want to add a branch just for this 🤔 Especially in the LTCGI module that also gets used by world shaders.

The v2 of the toon shader (which is what I assume this is meant to be used with) could probably support an extra spot where you posterize the LTCGI results in its own module.

However, thinking about it some more it feels like doing something like using the Toon Ramp and other shading settings might be what you actually want? Then instead of just pure posterization with discrete steps - you could have full ramp-based control over how the diffuse shading from LTCGI is applied? 🤔

In a separate LTCGI module, or using a compiler directive in the current one?
I could see having a separate LTCGI module for Toon could be useful for adding more post effects or configuration to the LTCGI Toon module.

I hadn't really considered a Toon Ramp, though that could be useful and easier to customize.

And yes this effect is primarily for LTCGI on Toon, aiming to make it look more "Toony" to fit with the aesthetic.

orels1 · 2025-03-05T00:49:08Z

In a separate LTCGI module, or using a compiler directive in the current one?

Probably a separate module
So with how v2 toon is set up - every lighting calculation is powered by the module itself, since the Toon shader is essentially just a collection of loosely connected effects.

So for this kinda thing i could imagine LTCGI putting data into something like
half3 customGIDiffuse and half3 customGISpecular, so then you can define your module that runs late which then modifies those in some way. Before the shader lighting model composites them all together

fundale · 2025-03-07T11:13:17Z

Gave Toon it's own LTCGI module with Texture Ramp support.
Tried messing around with customGIDiffuse and customGISpecular however they appear to only function in a baked state

orels1 · 2025-03-07T19:15:17Z

oh I meant that I could set up something like that for the 2.0 version, not the current one

fundale · 2025-03-10T00:33:43Z

The customGI* or the Ramping / separate module?

orels1 · 2025-03-11T20:23:28Z

the customGI part

fundale · 2025-03-11T22:07:53Z

Ah ok

orels1 · 2025-03-18T08:51:59Z

The v7.0.0-dev.8 of the shaders now has support for customGISpecular and customGIDiffuse which you can access via %CustomGI functions, similar to how LTCGI module did it on Dev already.

This is also supported by the Toon shader now.
I would recommend also adding a very high order number to the posterization module since you'd want it to always run last, e.g.

%CustomGI("LTCGICustomGIPosterize", 1000)
{
    void LTCGICustomGI(MeshData d, SurfaceData o, inout half3 customGISpecular, inout half3 customGIDiffuse)
    {
        // modify custom GI stuff before it gets composited with the rest of the lighting
    }
}

fundale · 2025-03-19T14:32:38Z

Updated the Toon LTCGI and CustomGI Ramp modules, thought having it as a separate module would become useful for providing Toon Ramping for other CustomGI FX (perhaps AreaLit and VRSLGI).

Also should I remove the LTCGI Toon module from V1?

orels1 · 2025-03-19T18:44:41Z

Have you tested it in Toon v1? As I'm pretty sure toon v1 doesn't have any hook points for %CustomGIFunctions in the fragment function 🤔

fundale · 2025-03-20T21:05:29Z

I have not tested the V2 LTCGI Toon Module with V1 Toon,
I'll check and make sure the V1 LTCGI Toon module still works with V1 Toon

fundale · 2025-03-20T21:14:55Z

The V1 LTCGI Toon Module still functions with V1 Toon, using %Color however it doesn't work with %CustomGI

orels1 · 2025-03-20T23:15:20Z

yeah, ok, that's about what I expected, as Toon v1 doesnt have %CustomGI hooks

orels1 · 2025-05-11T02:45:48Z

Packages/sh.orels.shaders.generator/Runtime/Sources/Modules/Toon/LTCGI.orlsource

+                if (_LTCGIClampBrightness) {
+                    half3 hsv = RGB2HSV(ltcgiData.specular);
+                    hsv.z = tanh(hsv.z) * max(0, _LTCGIMaxBrightness);
+                    indirectSpecular += HSV2RGB(hsv) * _LTCGISpecularIntensity;
+                } else {
+                    indirectSpecular += ltcgiData.specular * _LTCGISpecularIntensity;
+                }
+                indirectDiffuse += ltcgiData.diffuse * _LTCGIDiffuseIntensity;


Just getting back to this. Shouldn't this also include all the ramp stuff like you did in the %%Color block?

I don't believe that is ever used in Toon V1? but I'll include it anyways.

orels1 · 2025-05-11T05:59:40Z

Packages/sh.orels.shaders.generator/Runtime/Sources/Modules/Toon/v2/LTCGI.orlsource

+%Color("LTCGIColor")
+{
+    void LTCGIColor(MeshData d, FragmentData i, inout half4 FinalColor, bool facing)
+    {
+        #if defined(ORL_LIGHTING_MODEL_VFX)
+        {
+            #if defined(PLAT_QUEST)
+            if (!_LTCGIEnableOnMobile) return;
+            #endif
+
+            #if defined(INTEGRATE_LTCGI)
+                LTCGIAccumulatorStruct ltcgiData = (LTCGIAccumulatorStruct) 0;
+
+                float3 viewDir = d.worldSpaceViewDir;
+                if (!facing)
+                {
+                    viewDir = -d.worldSpaceViewDir;
+                }
+
+                LTCGI_Contribution(
+                    ltcgiData,
+                    d.worldSpacePosition.xyz,
+                    d.worldNormal.xyz,
+                    viewDir,
+                    saturate(0.5 + _LTCGIRoughnessModifier),
+                    d.uv1.xy
+                );
+
+                if (_LTCGIClampBrightness) {
+                    half3 hsv = RGB2HSV(ltcgiData.specular);
+                    hsv.z = tanh(hsv.z) * max(0, _LTCGIMaxBrightness);
+                    FinalColor.rgb += HSV2RGB(hsv) * _LTCGISpecularIntensity;
+                } else {
+                    FinalColor.rgb += ltcgiData.specular * _LTCGISpecularIntensity;
+                }
+                FinalColor.rgb += ltcgiData.diffuse * _LTCGIDiffuseIntensity;
+                if (_LTCGIAlphaPremultiply)
+                {
+                    FinalColor.rgb *= FinalColor.a;
+                }
+            #endif
+        }
+        #endif
+    }
+}


is this needed? 🤔
wouldn't the main LTCGI module (non-toon) already handle that

The main LTCGI module could with a compiler directive,
Toon needs "d.worldNormal.xyz" and has no "o.Smoothness",
Other than that it's pretty much the same.

Does Toon V2 provide a directive?

Yeah, as of a couple dev releases ago, its the same as TOON, but with V2 at the end
ORL_LIGHTING_MODEL_TOON_V2

However, my point here was that this part is limited to ORL_LIGHTING_MODEL_VFX and im not sure why do we need a separate VFX-only block in a toon version of LTCGI, when the main LTCGI already works with VFX

We do not need a Toon V2 specific variant of LTCGI, that is an oversight on my part.

I was referring to having a slightly different function call in the existing LTCGI (removing the LTCGI Toon V2), that would use d.worldNormal instead of d.normal and skip o.Smoothness as it is currently not defined in the Toon V2 base.

I mean i dont mind a toon v2 specific module, here I meant specifically that the Toon v2 version of the module for some reason has code that is ifdefed under VFX, which you'd never use the toon LTCGI module with, is all

Oh, I didn't see that, will look into that then.

That's from the original LTCGI module for PBR, I didn't realize it wasn't being used anymore.

Also why does the PBR LTCGI Module use NORMAL instead of WORLDNORMAL?

So the "PBR" module is meant to be used for both PBR and VFX, only Toon needed special treatment. So you dont need to add a Color block for just VFX in the Toon v2. As it is only meant to be used in the Toon v2 lighting model.

As for Normal vs WorldNormal

Both of them are World Normals inside the FragmentBase function, the "correct" move there would be to do what I did in toon v2 and have Normal be Tangent Normal and then WorldNormal be the.. well world normal.

But due to lack of foresight - i just converted o.Normal to world space up-top in the PBR Fragment Base, as for the longest time - there was no way to extend the actual FragmentBase function from an outside module. And then i saved the original o.Normal (which is what the individual modules interact with) into tangentNormal at the top of FragmentBase as well

Then when I wrote Toon v2, since the whole lighting function is modularized - i ended up adding another surface struct property - WorldNormal and left Normal untouched, so its very clear which is which.

But that in turn created conflicts with CustomGI modules. Which are unfortunate, but I generally think that it was the better choice (and I might just change the PBR to use the new naming as well? but im still thinking about it)

Alright, I've removed the %Color from Toon V2 and %CustomGI from Toon V1,
And model compiler directive checks for both seeing as they should be unused now.

Add Posterize option to LTCGI Diffuse

01c5c71

Switch to LTCGI Ramp in dedicated module

c4fba3b

fundale added 2 commits March 19, 2025 07:49

Merge branch 'orels1:dev' into dev

3096a68

Update LTCGI and Ramp to Toon V2

543de0e

Merge branch 'orels1:dev' into dev

85dd800

orels1 reviewed May 11, 2025

View reviewed changes

fundale added 2 commits May 10, 2025 23:17

Merge branch 'orels1:dev' into dev

274f758

Include LTCGI ToonRamp in v1 CustomGI

5496e83

orels1 reviewed May 11, 2025

View reviewed changes

fundale added 5 commits May 11, 2025 23:32

Remove unused %Color pass for Toon V2 LTCGI

d54005a

Remove unused %CustomGI pass from Toon V1 LTCGI

2b3b651

Remove unused compiler directive checks

6adf83c

Multiply LTCGI Emission by Albedo in Toon V1

ee63844

Merge branch 'orels1:dev' into dev

115899f

orels1 merged commit 7a1d43f into orels1:dev May 25, 2025

Add Posterize option to LTCGI Diffuse #85

Add Posterize option to LTCGI Diffuse #85

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