chore: remove skylighting boost in favour of ibl

[doodlum]

Summary by CodeRabbit

• New Features

  • No user-facing features added.

• Bug Fixes

  • Corrected skylight diffuse visibility to prevent normal-based overbrightening.
  • Standardized gamma/linear handling in the skylight pass for more accurate colors.
  • Removed unintended skylight modulation of directional ambient on foliage, yielding more natural grass lighting and reduced washout.
  • Improved consistency of ambient lighting across scenes and viewing angles.
  • No settings changes required; visuals update automatically.

[coderabbitai]

Walkthrough

Removes normal-based MinDiffuseVisibility scaling and several skylightingDiffuse multiplications across shaders. Adjusts gamma/linear handling in Lighting.hlsl by removing a pre-multiply GammaToLinear step, leaving final gamma conversion only. Grass shaders stop modulating directional ambient color with skylightingDiffuse. No public interfaces changed.

Changes

Cohort / File(s)	Summary
Remove MinDiffuseVisibility scaling package/Shaders/AmbientCompositeCS.hlsl	Deleted the normal-based boost factor multiplying skylightingDiffuse; kept fade/mix flow unchanged.
Adjust skylighting gamma handling package/Shaders/Lighting.hlsl	Removed pre-multiply gamma-to-linear conversion and the MinDiffuseVisibility-based scaling; retains a single skylightingDiffuse application before final gamma.
Stop applying skylighting to grass ambient package/Shaders/RunGrass.hlsl	Removed multiplications of directionalAmbientColor by skylightingDiffuse and the MinDiffuseVisibility factor in two GRASS_LIGHTING paths; gamma conversion remains at the end.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Suggested reviewers

• alandtse
• Pentalimbed

Poem

I twitch my ears at skies so bright, 🌤️
No extra boost, just honest light.
Grass waves softly, colors true,
Gamma’s tidy, shaders new.
I thump with joy—so subtly grand,
Diffuse and calm across the land. 🐇✨

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📜 Recent review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 3bed38c and 6cb4f45.

📒 Files selected for processing (3)

• package/Shaders/AmbientCompositeCS.hlsl (0 hunks)
• package/Shaders/Lighting.hlsl (0 hunks)
• package/Shaders/RunGrass.hlsl (0 hunks)

💤 Files with no reviewable changes (3)

• package/Shaders/AmbientCompositeCS.hlsl
• package/Shaders/RunGrass.hlsl
• package/Shaders/Lighting.hlsl

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (3)

• GitHub Check: Validate shader compilation (Flatrim, .github/configs/shader-validation.yaml)
• GitHub Check: Build plugin and addons
• GitHub Check: Validate shader compilation (VR, .github/configs/shader-validation-vr.yaml)

✨ Finishing Touches

🧪 Generate unit tests

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch no-skylighting-boost

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[github-actions]

Using provided base ref: 3bed38c
Using base ref: 3bed38c
Base commit date: 2025-09-08T17:00:21+01:00 (Monday, September 08, 2025 05:00 PM)
No actionable suggestions for changed features.

[github-actions]

✅ A pre-release build is available for this PR:
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