fix(UI): Background Blur with Upscaling

[Dlizzio]

Fixes UI background blur with Upscaling.

Summary by CodeRabbit

• New Features

  • Enhanced background blur with rounded-corner masking, shader-driven composite pass, and improved UI compositing to prevent HUD bleed-through.
  • Deeper integration with upscaling for higher-quality blurred backgrounds.

• Behavior Changes

  • Background blur enabled by default for bundled themes.

• Chores

  • Resource and lifecycle handling refinements for more robust initialization and cleanup.

[coderabbitai]

📝 Walkthrough

Walkthrough

Adds DX12→D3D11 blur resource types and getters (DX12SwapChain::BlurResources, DX12SwapChain::GetBlurResources, Upscaling::GetBlurResources) and integrates upscaling-aware UI composition, rounded-corner masking, composite/clear shaders, and UI buffer handling into BackgroundBlur rendering.

Changes

Cohort / File(s)	Summary
Upscaling public API src/Features/Upscaling.h, src/Features/Upscaling.cpp	Added using BlurResources = DX12SwapChain::BlurResources; and BlurResources GetBlurResources() const which proxies to DX12 swap-chain blur resources when the D3D12 swap-chain proxy is active, otherwise returns an empty struct.
DX12 swap-chain blur accessors src/Features/Upscaling/DX12SwapChain.h, src/Features/Upscaling/DX12SwapChain.cpp	Introduced struct BlurResources (backbuffer and UI texture, RTV, SRV fields) and BlurResources GetBlurResources() const that assembles and returns available wrapped D3D11 resources.
Background blur pipeline & shaders src/Menu/BackgroundBlur.cpp, src/Menu/BackgroundBlur.h, package/Shaders/Menu/BackgroundBlurComposite.hlsl	Expanded PerformBlur signature to accept source SRV, optional UI SRV/RTV and corner radius; added composite & clear pixel shaders, window constant buffer, composite blend state, cached non-upscaling SRV, rounded-rectangle SDF masking, UI clear/composite steps, and resource lifecycle/cleanup updates.
Theme defaults package/SKSE/Plugins/CommunityShaders/Themes/*.json, src/Menu.h	Enabled BackgroundBlur by default in several theme JSON files and changed ThemeSettings::BackgroundBlurEnabled default to true.
Public API reductions src/Menu/BackgroundBlur.h	Removed older public helpers: CreateBlurTextures, the old-signature PerformBlur, GetEnabled, IsEnabled, and GetTextureDimensions; remaining public surface limited to Initialize, RenderBackgroundBlur, Cleanup.

Sequence Diagram

sequenceDiagram
    participant Menu as BackgroundBlur
    participant Ups as Upscaling
    participant DXS as DX12SwapChain
    participant D11 as D3D11Context
    Menu->>Ups: Request GetBlurResources()
    Ups->>DXS: GetBlurResources() (if d3d12SwapChainActive)
    DXS-->>Ups: BlurResources {BackbufferTex/RTV/SRV, UIBufferSRV/RTV}
    Ups-->>Menu: BlurResources
    Menu->>D11: Bind backbuffer SRV/RTV and optional UI SRV/RTV
    Menu->>D11: Run composite PS (rounded-corners) -> write UI buffer
    Menu->>D11: Clear UI buffer in rounded region via clear PS
    Menu->>D11: Perform downsample blur passes
    Menu->>D11: Upscale final composite into target RTV

Loading

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• feat(UI): add gaussian blur shader core files #1595: Modifies BackgroundBlur flow and shaders; directly overlaps PerformBlur/composite changes.
• chore(upscaling): simplify interop and upscale methods #1514: Alters Upscaling/DX12SwapChain interop and resource exposure; related to the new blur resource getters.
• fix: misc fixes #1474: Touches DX12SwapChain/Upscaling surface and swap-chain interop that align with the BlurResources additions.

Suggested reviewers

• davo0411
• doodlum
• alandtse

Poem

🐇 I hop through frames and swap-chain light,
I bring soft edges, round and bright,
I blend the HUD with world anew,
A fuzzy veil in pixels true,
Hooray — the bunny blurred the sight!

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 6.67% 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 describes the main fix: enabling background blur functionality when upscaling is enabled, which aligns with the core changes adding blur resource accessors and shader implementations.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

No actionable comments were generated in the recent review. 🎉

🧹 Recent nitpick comments

src/Menu/BackgroundBlur.cpp (3)

77-79: Raw pointer cache key is safe here, but a comment clarifying the invariant would help.

cachedSourceTexture is only used for identity comparison (line 684), and cachedSourceSRV holds a strong reference preventing the texture from being destroyed. The raw pointer can never become a stale comparison target while the SRV exists. A brief inline comment noting this invariant would help future readers.

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612-626: enabled/initialized reads are not protected by resourceMutex.

RenderBackgroundBlur reads enabled (line 614), initialized, and initializationFailed (line 618) without holding resourceMutex, while Initialize/Cleanup write them under the lock. If these functions can run on different threads, this is a data race. If rendering is guaranteed single-threaded, consider documenting that assumption or making the flags std::atomic<bool>.

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711-752: State save/restore is repeated per window in the blur loop.

Each PerformBlur call (line 751) independently saves and restores the full D3D11 pipeline state (render targets, viewports, rasterizer state). With multiple blurred windows, this overhead multiplies. Consider hoisting the state save/restore out of PerformBlur and around the loop instead, passing the saved state or using a RAII state block.

This is a minor perf concern for the typical case (few windows) but worth noting.

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[Dlizzio]

@coderabbitai review

[coderabbitai]

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Review triggered.

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[github-actions]

Using provided base ref: 9508559
Using base ref: 9508559
Base commit date: 2026-02-09T12:18:46Z (Monday, February 09, 2026 12:18 PM)
No actionable suggestions for changed features.

[davo0411]

@doodlum review requested as I am unsure of any negative ramifications of adding things to swapchain for this.

Dlizzio has reported no FPS differences measurable. Core code is same as mine, just fixed to actually apply to the world lol

[Dlizzio]

@coderabbitai review

[coderabbitai]

✅ Actions performed

Review triggered.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[github-actions]

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