fix(wetness): fix water roughness and normal

[jiayev]

This pull request updates the wetness effects calculations in the Lighting.hlsl shader to use vertexNormal instead of worldNormal for several key computations. The changes improve the accuracy of wetness rendering by ensuring the correct normal is used for wetness-related factors, and by refining how wetness influences material roughness and normal blending.

Wetness effects improvements:

• Changed initialization of wetnessNormal to use vertexNormal.xyz instead of worldNormal, ensuring wetness calculations are based on the actual vertex normal.
• Updated calculation of minWetnessAngle to use vertexNormal.z for more precise wetness angle determination.
• Modified the call to WetnessEffects::GetRainDrops to use wetnessNormal instead of worldNormal, improving raindrop placement accuracy.
• Blended wetnessNormal with worldNormal based on puddle intensity, making the final normal more representative of wet surface conditions.

Material property adjustments:

• Changed the interpolation of material.Roughness to use wetnessGlossinessSpecular instead of wetnessReflectance.x, providing a more consistent response to wetness glossiness in the material properties.

Summary by CodeRabbit

• Bug Fixes
  • Improved wet-surface shading: raindrop highlights and occlusion now render more consistently.
  • Smoother puddle blending between dry and wet regions for more realistic reflectivity and roughness.
  • Enhanced overall lighting on wet materials for more accurate wetness appearance.

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[github-actions]

Using provided base ref: 331b492
Using base ref: 331b492
Base commit date: 2026-01-15T18:32:24+10:00 (Thursday, January 15, 2026 06:32 PM)
No actionable suggestions for changed features.

[github-actions]

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[jiayev]

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📝 Walkthrough

Walkthrough

This PR modifies the wetness shading calculations in package/Shaders/Lighting.hlsl: wetnessNormal is now initialized from vertex-space normals, raindrop and occlusion use the vertex-derived normal blended with worldNormal by puddle, and wet-surface roughness uses wetnessGlossinessSpecular instead of wetnessReflectance.x.

Changes

Cohort / File(s)	Summary
Wetness shader calculations package/Shaders/Lighting.hlsl	Switched wetnessNormal initialization from worldNormal to vertexNormal.xyz; changed minWetnessAngle to use vertexNormal.z; updated raindrop/occlusion computations to use wetnessNormal; added wetnessNormal = lerp(worldNormal.xyz, wetnessNormal, saturate(puddle)); replaced wetnessReflectance.x with wetnessGlossinessSpecular in wet roughness calculations.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• chore(wetness effects): wetness improvements and add fresnel #1468 — Modifies the same wetness-related shader logic in package/Shaders/Lighting.hlsl (wetnessNormal/raindrop handling and wetness glossiness/specular usage).

Suggested reviewers

• alandtse
• davo0411

Poem

🐰🌧️
I hop through normals, vertex-born,
Blend puddles where the light is warm,
Raindrops dance on glossy skin,
A shader's wink, a rabbit grin.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix(wetness): fix water roughness and normal' directly and clearly summarizes the main changes, which address wetness effect calculations for both water roughness and normal mapping.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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• package/Shaders/Lighting.hlsl

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Files:

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🧠 Learnings (3)

📓 Common learnings

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-06-24T07:17:36.604Z
Learning: When reviewing PRs, always clarify the scope if there are multiple related features or dependencies. WeatherPicker was a separate PR that was already merged, while this PR focuses specifically on WetnessEffects climate preset system enhancements.

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-07-05T05:20:45.823Z
Learning: In the skyrim-community-shaders repository, file deletion error handling improvements that replace existence checks and try-catch blocks with std::filesystem::remove error-code-based approaches are considered bug fixes rather than refactoring, as they address inadequate error handling and misleading log messages.

Learnt from: jiayev
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
Learning: ISReflectionsRayTracing.hlsl and ISWorldMap.hlsl in the skyrim-community-shaders repository are image-space post-processing shaders that perform color sampling and blending operations that need proper linear color space handling for the linear lighting system. ISReflectionsRayTracing handles screen-space reflections and should use conditional Color::IrradianceToLinear/Gamma conversions similar to ISCompositeLensFlareVolumetricLighting.hlsl. ISWorldMap performs 7x7 color accumulation that should be done in linear space similar to the pattern used in ISSAOComposite.hlsl.

📚 Learning: 2025-08-03T18:37:19.690Z

Learnt from: jiayev
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
Learning: ISReflectionsRayTracing.hlsl and ISWorldMap.hlsl in the skyrim-community-shaders repository are image-space post-processing shaders that perform color sampling and blending operations that need proper linear color space handling for the linear lighting system. ISReflectionsRayTracing handles screen-space reflections and should use conditional Color::IrradianceToLinear/Gamma conversions similar to ISCompositeLensFlareVolumetricLighting.hlsl. ISWorldMap performs 7x7 color accumulation that should be done in linear space similar to the pattern used in ISSAOComposite.hlsl.

Applied to files:

• package/Shaders/Lighting.hlsl

📚 Learning: 2025-08-17T18:37:35.839Z

Learnt from: CR
Repo: doodlum/skyrim-community-shaders PR: 0
File: .github/copilot-instructions.md:0-0
Timestamp: 2025-08-17T18:37:35.839Z
Learning: Applies to features/*/Shaders/**/*.{hlsl,hlsli,fx,fxh} : Avoid GPU register/buffer conflicts in HLSL; verify register usage (e.g., with hlslkit buffer scanning)

Applied to files:

• package/Shaders/Lighting.hlsl

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🔇 Additional comments (3)

package/Shaders/Lighting.hlsl (3)

2306-2341: LGTM! Using vertex normal for wetness calculations is a sensible improvement.

The switch from worldNormal to vertexNormal for wetness angle and raindrop calculations is physically more accurate—water accumulation and flow should respond to the macro-scale geometry rather than fine surface details from normal maps.

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2368-2370: LGTM! The puddle-based normal blending creates smooth transitions.

The interpolation correctly transitions from the textured worldNormal (no puddle) to the flatter vertex-derived wetnessNormal with ripple effects (full puddle), which matches expected visual behavior for water pooling on surfaces.

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3171-3176: LGTM! This fix correctly aligns roughness interpolation with the normal blending.

Using wetnessGlossinessSpecular (which directly represents wetness glossiness based on puddle/shore effects) is semantically correct and consistent with the normal lerp on line 3173. The previous use of wetnessReflectance.x was inconsistent since wetnessReflectance represents indirect specular reflectance weights rather than surface glossiness.

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