ShadowRampMask on XiexeToon is non-functional

[StarfishHidari]

Describe the bug?

The ShadowRampMask field on XiexeToon does not work, and has not worked since XiexeToon was originally implemented as far as I could find.

This was originally reported back in 2021 here; Neos-Metaverse/NeosPublic#2091

To Reproduce

• Create a new XiexeToon material
• Put any texture into the ShadowRampMask field
• You will notice this has no effect on the shadowramp when a light is shone on the surface

Expected behavior

When using a ShadowRampMask, it should mask where the shadow ramp affects.

Screenshots

In this screenshot you can see that both of these spheres have identical material setups, except one has a texture in the ShadowRampMask field, but the shadows are the same on both meshes.

Resonite Version Number

Beta 2023.10.13.743

What Platforms does this occur on?

Windows

What headset if any do you use?

Valve Index

Log Files

DESKTOP-MU428FM - 2023.10.13.743 - 2023-10-13 19_36_57.log

Additional Context

This also has no effect on shadow rims either, though I am unsure if it is intended to affect shadow rims or not.

Reporters

Hidi

[SupersonicNK]

Actually, it works as intended (by the shader's creator). It's just not self-explanatory.
ShadowRampMask actually determines the Y coordinate the shadows sample from the ShadowRamp texture- try putting a separate gradient on the top and bottom halves of the ramp. The darker the color is, the lower on the texture it samples.
See this image: (Note that the ramp texture is clamped vertically, otherwise the White part of the ramp would sample from the top of the texture again.)

[StarfishHidari]

Actually, it works as intended (by the shader's creator). It's just not self-explanatory. ShadowRampMask actually determines the Y coordinate the shadows sample from the ShadowRamp texture- try putting a separate gradient on the top and bottom halves of the ramp. The darker the color is, the lower on the texture it samples. See this image: (Note that the ramp texture is clamped vertically, otherwise the White part of the ramp would sample from the top of the texture again.)

Ahh, thank you for the info! I hadn't been able to find any information on this in the past so this helps a lot. Hopefully a wiki will be up soon so this can be documented somewhere more accessible ^^

[The-furf-of-July]

Is the mask based on the lighting, or the UV map of the mesh?

I might be getting confused by the term "lower" here, due to the rotation of the textures.

[SupersonicNK]

Is the mask based on the lighting, or the UV map of the mesh?

I might be getting confused by the term "lower" here, due to the rotation of the textures.

The mask is based on UVs. The ShadowRampMask picks which row of pixels to use for shading from the ShadowRamp texture on the given UV.
The closer the mask's color at that UV is to black, the lower the row on the ShadowRamp texture.

The sphere has an unfortunate rotation in the image I provided, so it looks like the mask is flipped horizontally (evidently, that confused me too as I said the white part of the mask would "sample from the top again" if not clamped, when it would have wrapped back to the bottom). That's my bad.