fix(llf): guard against null bsLight/niLight

[alandtse]

Null-check bsLight and niLight before dereferencing in BSLightingShader_SetupGeometry_GeometrySetupConstantPointLights. Use a write index so StrictLights[] stays contiguous when entries are skipped, and update NumStrictLights to the actual written count. Also guard the ShadowBitMask loop against null bsLight.

A BSLight can have a null NiLight smart pointer when the underlying light object is destroyed while still referenced in a render pass. Observed crash: RSI=null (niLight), RCX=0x110 (GetLightRuntimeData SE offset), +0x0C (diffuse) -> access at 0x11C.

Summary by CodeRabbit

• Bug Fixes
  • Fixed light rendering to properly handle complex lighting scenarios and prevent visual artifacts.
  • Improved shadow mask computation for more accurate lighting calculations across diverse scene conditions.
  • Enhanced overall rendering stability and quality in light-intensive environments.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 663ff29c-c0b0-49e1-8160-a3962cbbf205

📥 Commits

Reviewing files that changed from the base of the PR and between 4c0a4ea and ad7ce66.

📒 Files selected for processing (1)

• src/Features/LightLimitFix.cpp

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📝 Walkthrough

Walkthrough

Modified light population logic in the point lights setup function to skip null entries using a separate write index counter, ensuring only valid lights are stored and counted. Changed shadow mask bit-shifting from signed to unsigned integers for proper unsigned behavior.

Changes

Cohort / File(s)	Summary
Light Population Fix src/Features/LightLimitFix.cpp	Refactored strict light population to use a separate writeIdx counter, skipping null bsLight or niLight entries while maintaining a compact array. Updated NumStrictLights to reflect actual count. Changed shadow mask bit-shift from signed (1 << maskIndex) to unsigned (1u << maskIndex).

Estimated Code Review Effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly Related PRs

• doodlum/skyrim-community-shaders#1288: Modifies the same light-setup code and handles StrictLightData.ShadowBitMask bit accumulation and shifting.

Suggested Reviewers

• doodlum

Poem

🐰 Strict lights now skip the nulls with care,
A separate counter, placed just there,
No empty shadows in our array,
Unsigned shifts light the proper way! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: adding null checks for bsLight and niLight before dereferencing in light shader code.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[github-actions]

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[github-actions]

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