fix(VL): broken VL with VL core feature disabled

[sicsix]

• with the VL core feature disabled but VL still enabled in the game's INI files it would replace the VL shaders with optimised versions without patching the assembly required for the new shaders
• now ensures that the feature is enabled before replacing the shaders, effectively falling back to vanilla VL

Fixes #1349

Summary by CodeRabbit

• Bug Fixes
  • Improved the reliability of volumetric lighting effects by refining the logic for handling compute shaders, ensuring consistent behavior when applying blur and lighting techniques.

[coderabbitai]

Walkthrough

The patch restructures the compute shader dispatch logic for volumetric lighting in Renderer_DispatchCSShader::thunk. All volumetric lighting shader handling, including both generation/raymarch and blur passes, is now gated under a single check for the volumetric lighting feature being active, with additional handling for blur shaders when a shader is already dispatched.

Changes

Cohort / File(s)	Change Summary
Volumetric Lighting Shader Dispatch Logic src/Hooks.cpp	Refactored the compute shader dispatch logic for volumetric lighting. All relevant shader handling is now under a single vl.loaded check, with consolidated logic for both generation/raymarch and blur passes. No changes to public interfaces.

Sequence Diagram(s)

sequenceDiagram
    participant Renderer
    participant VolumetricLighting
    participant ShaderManager

    Renderer->>VolumetricLighting: Check if loaded
    alt VolumetricLighting loaded
        alt CurrentlyDispatchedShader is null
            Renderer->>ShaderManager: Get Generate/Raymarch Shader
            ShaderManager-->>Renderer: Return Shader
        else CurrentlyDispatchedShader not null
            Renderer->>ShaderManager: Get BlurH/BlurV Shader
            ShaderManager-->>Renderer: Return Shader
            Renderer->>VolumetricLighting: SetDimensionsCB(), SetGroupCounts*
        end
    else VolumetricLighting not loaded
        Renderer->>ShaderManager: Fallback to default dispatch logic
    end

Loading

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Assessment against linked issues

Objective	Addressed	Explanation
Fix volumetric lighting dispatch logic to address lighting bug (white/black screen when looking up) (#1349)	✅

Assessment against linked issues: Out-of-scope changes

No out-of-scope changes detected.

Possibly related PRs

• perf(VL): replace ping-pong dispatches with single pass #1209: Refactored shader dispatch logic for volumetric lighting, introducing optimizations and centralizing shader management.

Suggested reviewers

• alandtse

Poem

In the glow of volumetric light,
A rabbit tweaks shaders just right.
No more white or black when you look to the sky—
The lighting’s now fixed, oh my!
With dispatches clear and logic anew,
Your Skyrim world shines with a magical hue.
🐇✨

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📜 Recent review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 21e29d0 and d0861e9.

📒 Files selected for processing (1)

• src/Hooks.cpp (1 hunks)

🧰 Additional context used

🧠 Learnings (7)

📓 Common learnings

Learnt from: alandtse
PR: doodlum/skyrim-community-shaders#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
PR: doodlum/skyrim-community-shaders#0
File: :0-0
Timestamp: 2025-08-03T18:37:19.673Z
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.

Learnt from: alandtse
PR: doodlum/skyrim-community-shaders#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: jiayev
PR: doodlum/skyrim-community-shaders#0
File: :0-0
Timestamp: 2025-07-18T15:21:03.641Z
Learning: In the skyrim-community-shaders rendering pipeline, materials with alpha < 1 or alpha blending enabled are rendered in non-deferred mode rather than deferred mode. This means issues with dynamic cubemaps on transparent materials are actually non-deferred rendering issues.

Learnt from: alandtse
PR: doodlum/skyrim-community-shaders#577
File: src/Features/WetnessEffects.h:36-36
Timestamp: 2025-06-08T11:25:14.536Z
Learning: In the skyrim-community-shaders project, boolean flags in C++ structs that interface with HLSL shaders use `uint` type instead of `bool` for compatibility reasons. This ensures consistent size, alignment, and cross-platform compatibility when passing data to shader constant buffers.

📚 Learning: isreflectionsraytracing.hlsl and isworldmap.hlsl in the skyrim-community-shaders repository are imag...

Learnt from: jiayev
PR: doodlum/skyrim-community-shaders#0
File: :0-0
Timestamp: 2025-08-03T18:37:19.673Z
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:

• src/Hooks.cpp

📚 Learning: in the skyrim-community-shaders repository, file deletion error handling improvements that replace e...

Learnt from: alandtse
PR: doodlum/skyrim-community-shaders#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.

Applied to files:

• src/Hooks.cpp

📚 Learning: in the skyrim-community-shaders project, boolean flags in c++ structs that interface with hlsl shade...

Learnt from: alandtse
PR: doodlum/skyrim-community-shaders#577
File: src/Features/WetnessEffects.h:36-36
Timestamp: 2025-06-08T11:25:14.536Z
Learning: In the skyrim-community-shaders project, boolean flags in C++ structs that interface with HLSL shaders use `uint` type instead of `bool` for compatibility reasons. This ensures consistent size, alignment, and cross-platform compatibility when passing data to shader constant buffers.

Applied to files:

• src/Hooks.cpp

📚 Learning: in the skyrim-community-shaders project, boolean flags in c++ structs that interface with hlsl shade...

Learnt from: alandtse
PR: doodlum/skyrim-community-shaders#577
File: src/Features/WetnessEffects.h:36-36
Timestamp: 2025-06-08T11:25:14.536Z
Learning: In the skyrim-community-shaders project, boolean flags in C++ structs that interface with HLSL shaders use `uint` type instead of `bool` for compatibility reasons. This ensures consistent 4-byte size, proper 16-byte alignment in constant buffers, and cross-platform compatibility when passing data between C++ and HLSL shaders.

Applied to files:

• src/Hooks.cpp

📚 Learning: default parameter values are supported in the hlsl compiler used by the skyrim-community-shaders pro...

Learnt from: alandtse
PR: doodlum/skyrim-community-shaders#577
File: features/Wetness Effects/Shaders/WetnessEffects/WetnessEffects.hlsli:57-61
Timestamp: 2025-06-17T05:40:22.785Z
Learning: Default parameter values are supported in the HLSL compiler used by the skyrim-community-shaders project, contrary to standard HLSL (FXC/DXC) limitations.

Applied to files:

• src/Hooks.cpp

📚 Learning: in the skyrim community shaders project, the `smoothdrawcalls` array in the `state` class is declare...

Learnt from: davo0411
PR: doodlum/skyrim-community-shaders#1070
File: src/State.cpp:79-83
Timestamp: 2025-05-30T11:44:15.542Z
Learning: In the Skyrim Community Shaders project, the `smoothDrawCalls` array in the `State` class is declared as type `double` in `src/State.h`, which is the correct floating-point type for performing exponential moving average smoothing calculations.

Applied to files:

• src/Hooks.cpp

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• GitHub Check: Build plugin and addons

🔇 Additional comments (1)

src/Hooks.cpp (1)

966-984: LGTM! This change correctly fixes the broken VL issue.

The restructuring properly gates all volumetric lighting shader handling under the vl.loaded check. This prevents the mod from replacing VL shaders with optimized versions when the VL core feature is disabled, which was causing the lighting bug described in issue #1349. By consolidating all VL shader dispatch logic under this single guard, the code now falls back to vanilla VL behavior when the core feature is disabled, resolving the white/black screen artifacts when looking upward.

The additional handling for blur shaders with SetDimensionsCB() and SetGroupCountsHCS()/SetGroupCountsVCS() calls when CurrentlyDispatchedShader is not null also ensures proper setup for the blur passes.

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[github-actions]

Using provided base ref: 21e29d0
Using base ref: 21e29d0
Base commit date: 2025-08-03T13:01:00-07:00 (Sunday, August 03, 2025 01:01 PM)
No actionable suggestions for changed features.

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