refactor(water): replace hardcoded offset

[Copilot]

The code used a hardcoded 0x38 offset to access enableWaterTAA in the BSImagespaceShaderISTemporalAA structure, which is fragile across game updates and versions.

Changes

Upscaling.cpp

• Added local ExtendedTemporalAAStruct definition that extends CommonLib's partial UNK_BSImagespaceShaderISTemporalAA structure
• Structure includes enableWaterTAA at offset 0x38 with full memory layout
• Updated ConfigureTAA() and Main_PostProcessing::thunk() to use structured access via reinterpret_cast
• Added static_assert(sizeof(...) == 0x40) to verify layout
• Includes TODO comment to contribute structure extension to alandtse/CommonLibVR upstream

// Before
bool* enableWaterTAA = reinterpret_cast<bool*>(reinterpret_cast<uintptr_t>(BSImagespaceShaderISTemporalAA) + 0x38LL);
*enableWaterTAA = upscaleMethod == UpscaleMethod::kNONE || upscaleMethod == UpscaleMethod::kTAA;

// After  
auto* extendedStruct = reinterpret_cast<ExtendedTemporalAAStruct*>(BSImagespaceShaderISTemporalAA);
extendedStruct->enableWaterTAA = upscaleMethod == UpscaleMethod::kNONE || upscaleMethod == UpscaleMethod::kTAA;

Structure Layout

struct ExtendedTemporalAAStruct {
    BSImagespaceShaderISTemporalAA* shader;                     // 0x00
    BSImagespaceShader*             BSImagespaceShaderISTemporalAA_UI;     // 0x08
    BSImagespaceShader*             BSImagespaceShaderISTemporalAA_Water;  // 0x10
    bool                            taaEnabled;                 // 0x18
    std::uint8_t                    pad19[7];                   // 0x19
    std::uint64_t                   unk20;                      // 0x20 - needs RE
    std::uint64_t                   unk28;                      // 0x28 - needs RE
    std::uint64_t                   unk30;                      // 0x30 - needs RE
    bool                            enableWaterTAA;             // 0x38
    std::uint8_t                    pad39[7];                   // 0x39
};
static_assert(sizeof(ExtendedTemporalAAStruct) == 0x40);

Members at 0x20-0x30 remain as placeholders pending further reverse engineering work.

Implementation Notes

The structure extension is defined locally in this repository rather than in CommonLibSSE-NG. This avoids dependency on unpushed submodule commits while still providing the benefits of structured access. The structure should be contributed upstream to alandtse/CommonLibVR in a future PR, at which point the local definition can be removed.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Investigate hardcoded offset for enableWaterTAA in BSImagespaceShaderISTemporalAA</issue_title>
<issue_description>## Description
The code currently uses a hardcoded memory offset (0x38LL) to access the enableWaterTAA member in the BSImagespaceShaderISTemporalAA structure:

bool* enableWaterTAA = reinterpret_cast<bool*>(reinterpret_cast<uintptr_t>(BSImagespaceShaderISTemporalAA) + 0x38LL);

Location: src/Features/Upscaling.cpp:705

Tasks

• Investigate if CommonLibSSE/CommonLibVR has already reverse engineered the BSImagespaceShaderISTemporalAA structure. We use the ng branch of commonlibvr.
• If available in CommonLib, refactor to use the proper structure member instead of hardcoded offset
• If not available, perform RE work to properly define the structure
• Document the structure definition for maintainability

Context

Hardcoded offsets are fragile and can break with game updates or across different game versions. Using proper structure definitions from CommonLib (if available) or creating our own RE definitions would make this code more maintainable.

References

• PR: fix(upscaling): disable water TAA instead of enable #1726
• Comment: fix(upscaling): disable water TAA instead of enable #1726 (comment)
• Requested by: @alandtse</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Investigate hardcoded offset for enableWaterTAA in BSImagespaceShaderISTemporalAA #1727

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[alandtse]

There's a strange spare root file here. Also, are you saying Commonlib already has this structure or does it need to have it PRed?

[Copilot]

There's a strange spare root file here. Also, are you saying Commonlib already has this structure or does it need to have it PRed?

Fixed in f865286:

1. Removed the _codeql_detected_source_root symlink (build artifact)
2. Reverted CommonLibSSE-NG submodule to original commit - the structure does NOT exist in CommonLib yet

The extended structure is now defined locally in Upscaling.cpp with a TODO to contribute it to alandtse/CommonLibVR upstream. This avoids depending on unpushed submodule commits while still replacing the hardcoded offset.

[github-actions]

Using provided base ref: 43b7727
Using base ref: 43b7727
Base commit date: 2026-01-17T01:57:42Z (Saturday, January 17, 2026 01:57 AM)
No actionable suggestions for changed features.