fix(upscaling): replace NIS with RCAS for DLSS

[midona-rhel]

Changed it to RCAS for sharpening even for DLSS

should solve Issue #1616

Summary by CodeRabbit

• New Features

  • Added RCAS compute-based sharpening and integrated it into the upscaling pipeline.

• Changes

  • Unified sharpening to run during upscaling and DLSS post-processing; earlier initialization and streamlined texture handling.
  • Sharpening API renamed and clarified (ApplySharpening); default DLSS sharpness increased from 0.1 to 1.0.

• Removed

  • NVIDIA Integrated Sharpening (NIS) support, related hooks, and legacy NIS sharpening flow.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

Adds a new RCAS compute shader and C++ RCAS subsystem, integrates RCAS sharpening into Upscaling (renames the sharpener texture and ApplySharpening), removes NIS integration from Streamline, and wires SRV/UAV/CB/dispatch for an 8x8-thread-group RCAS pass.

Changes

Cohort / File(s)	Summary
RCAS Shader features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl	New HLSL compute shader implementing FidelityFX RCAS with RCASConfig cbuffer (sharpness), 3x3 neighborhood sampling, luma/noise/lobe calculations, boundary-safe sampling, and [numthreads(8,8,1)].
RCAS C++ Implementation src/Features/Upscaling/RCAS/RCAS.h, src/Features/Upscaling/RCAS/RCAS.cpp	New RCAS class with ctor/dtor, Initialize(), CreateComputeShader(), ApplySharpen(ID3D11ShaderResourceView*, ID3D11UnorderedAccessView*, float). Manages compute shader creation, rcasConfigCB, CB/SRV/UAV binding, dispatch ((w+7)/8,(h+7)/8), and cleanup.
Upscaling Integration src/Features/Upscaling.h, src/Features/Upscaling.cpp	Adds static RCAS rcas; renames nisSharpenerTexture → sharpenerTexture; renames ApplyNISSharpening() → ApplySharpening(); initializes RCAS earlier; routes sharpening to sharpenerTexture SRV/UAV and changes default sharpnessDLSS to 1.0f.
Streamline (NIS Removal) src/Features/Upscaling/Streamline.h, src/Features/Upscaling/Streamline.cpp	Removes NIS feature hooks, function pointers, header includes, ApplyNISSharpening declaration/implementation, and NIS runtime checks/logging.

Sequence Diagram(s)

sequenceDiagram
    participant Upscaling as Upscaling
    participant RCAS as RCAS Subsystem
    participant GPU as GPU/Compute Shader
    participant Resource as Texture Resources

    Upscaling->>RCAS: Initialize()
    RCAS->>GPU: Compile/create compute shader
    GPU-->>RCAS: Shader ready

    Upscaling->>Resource: Prepare input SRV & output UAV
    Resource-->>Upscaling: SRV/UAV available

    Upscaling->>RCAS: ApplySharpen(inputSRV, outputUAV, sharpness)
    RCAS->>RCAS: Update RCASConfig cbuffer (sharpness)
    RCAS->>GPU: Bind CB, SRV (t0), UAV (u0)
    RCAS->>GPU: Dispatch((width+7)/8,(height+7)/8,1)

    rect rgba(180,230,200,0.06)
      Note over GPU: For each 8x8 threadgroup\ncompute shader reads 3x3 neighborhood,\ncomputes luma/noise/lobe and writes sharpened pixel
    end

    GPU->>Resource: Write sharpened output
    RCAS->>GPU: Unbind CB/SRV/UAV
    RCAS-->>Upscaling: Sharpening complete

Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

• Inspect HLSL CB/register layout, numeric math, and threadgroup behavior in RCAS.hlsl.
• Verify RCAS::ApplySharpen SRV/UAV/CB bindings, dispatch dims, and resource state transitions in RCAS.cpp/RCAS.h.
• Confirm Upscaling integration (member rename, call sites, default sharpness change) in Upscaling.h/Upscaling.cpp.
• Check Streamline removals for remaining references or missing symbols in Streamline.*.

Possibly related PRs

• feat(upscaling): sharpening slider #1527 — Modifies the upscaling/sharpening pipeline and touches the same Upscaling files and sharpening members.
• feat(VR): enable upscaling #1507 — Changes the Upscaling subsystem; may overlap on resource/state handling and settings.
• feat: drs based upscaling #1443 — Adds RCAS sharpening and integrates similar shader/ApplySharpening symbols.

Suggested reviewers

• jiayev
• ArcEarth
• doodlum

Poem

🐰 I hopped through pixels, nibbling blur away,
I sample three-by-three where threadgroups play.
Constants set, I whisper sharpness in the air,
the GPU hums, I tidy each lobe with care.
Crisp frames bloom — I twitch, then bound away.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 11.11% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ 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 accurately reflects the main change: replacing NIS (NVIDIA Image Scaling) with RCAS (Robust Contrast Adaptive Sharpening) for DLSS sharpening functionality.

✨ Finishing touches

🧪 Generate unit tests (beta)

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

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• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

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[github-actions]

Using provided base ref: 39aa9d7
Using base ref: 39aa9d7
Base commit date: 2025-11-30T19:11:20-08:00 (Sunday, November 30, 2025 07:11 PM)

Actionable Suggestions

• Hair Specular: Action required; Needs version bump to 1-0-2

[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (6)

src/Features/Upscaling/RCAS/RCAS.h (1)

14-22: Add RAII cleanup for rcasConfigCB

rcasConfigCB is allocated with new in Initialize() but never freed. Even though this is small and mostly plugin‑lifetime, adding a destructor avoids leaks on device reset / teardown and keeps resource management consistent with the rest of the feature.

You can do:

 // RCAS.h
 class RCAS
 {
 public:
-	RCAS() = default;
+	RCAS() = default;
+	~RCAS();
@@
 	winrt::com_ptr<ID3D11ComputeShader> rcasComputeShader;
 	ConstantBuffer* rcasConfigCB = nullptr;
 };

// RCAS.cpp
+#include "RCAS.h"
+
+RCAS::~RCAS()
+{
+	delete rcasConfigCB;
+	rcasConfigCB = nullptr;
+}

Optionally, since all current call sites pass an explicit sharpness, you could also drop the default parameter on ApplySharpen or align it with the UI default to avoid confusion:

-	void ApplySharpen(ID3D11ShaderResourceView* inputTexture, ID3D11UnorderedAccessView* outputUAV, float sharpness = 0.15f);
+	void ApplySharpen(ID3D11ShaderResourceView* inputTexture, ID3D11UnorderedAccessView* outputUAV, float sharpness);

src/Features/Upscaling.h (1)

6-7: RCAS integration wiring looks good; double‑check DLSS sharpness default

The new RCAS wiring (header include, sharpenerTexture, static rcas instance, and ApplySharpening() entry point) lines up cleanly with the implementation in Upscaling.cpp and RCAS.cpp. No interface issues from these additions.

One behavioral tweak to sanity‑check: settings.sharpnessDLSS now defaults to 1.0f, and that value is passed directly into RCAS. That’s a fairly strong sharpening level to ship as the default for all DLSS users; if the goal is a more conservative change in perceived sharpness, consider lowering the default or mapping the UI slider non‑linearly so that “1.0” corresponds to a moderate RCAS strength.

Also applies to: 59-61, 142-143, 147-151, 167-167

src/Features/Upscaling.cpp (2)

890-891: Consider making rcas.Initialize() idempotent for repeated SetupResources calls

Calling rcas.Initialize() from SetupResources() ensures RCAS is ready once the main render targets exist, which is a good place to hook it. If SetupResources() can ever be invoked more than once (e.g., device reset / swap‑chain recreation), this will currently allocate a new ConstantBuffer each time without freeing the old one unless a destructor or guard is added on RCAS.

A simple pattern would be to early‑out in RCAS::Initialize() once rcasConfigCB is already set:

void RCAS::Initialize()
{
	if (rcasConfigCB)
		return;

	logger::info("[RCAS] Creating resources");
	CreateComputeShader();
	rcasConfigCB = new ConstantBuffer(ConstantBufferDesc<RCASConfig>());
}

This, combined with a destructor that deletes rcasConfigCB, keeps RCAS robust across potential reinitializations.

---

1422-1448: RCAS sharpening pass is well‑integrated into the DLSS path

ApplySharpening():

• Skips work when sharpnessDLSS <= 0.0f or sharpenerTexture is missing.
• Reads the underlying main render target resource from its SRV, unbinds OM render targets, and runs RCAS with main.SRV as input and sharpenerTexture’s UAV as output.
• Copies the sharpened result back into the original main resource and marks the render target dirty.

It’s only called when upscaleMethod == UpscaleMethod::kDLSS, so FSR/TAA paths are unaffected, and SRV/UAV aliasing is avoided by using a separate temporary texture plus the final CopyResource.

This looks correct and matches the intended “DLSS + RCAS sharpening” behavior. Any future generalization of RCAS (e.g., for other passes or off‑screen buffers) can build on this by ensuring the C++ side uses the input texture’s dimensions for dispatch, as noted in the RCAS.cpp comment.

Also applies to: 1474-1475

src/Features/Upscaling/RCAS/RCAS.cpp (2)

7-11: Zero‑initialize RCASConfig before uploading

RCASConfig currently has:

struct RCASConfig
{
	float sharpness;
	float3 pad;
};

and you only assign sharpness before uploading. While pad is just padding today, leaving it uninitialized is brittle if the HLSL side ever starts using those fields.

You can make this future‑proof by zero‑initializing the struct:

-	RCASConfig config;
-	config.sharpness = sharpness;
+	RCASConfig config{};
+	config.sharpness = sharpness;

This guarantees deterministic contents for the entire constant buffer.

Also applies to: 41-45

---

26-40: Derive RCAS dispatch size from the input texture instead of screenSize

ApplySharpen currently uses globals::state->screenSize to compute dispatch dimensions, which works when the input SRV wraps the full-screen render target but breaks if called on mismatched textures (half-res buffers, debug views, or different resolutions).

Query the SRV's underlying texture dimensions instead—this is idiomatic D3D11 and makes RCAS flexible:

uint32_t texWidth = 0;
uint32_t texHeight = 0;

if (inputSRV) {
	winrt::com_ptr<ID3D11Resource> resource;
	inputSRV->GetResource(resource.put());

	if (auto tex2D = resource.try_as<ID3D11Texture2D>()) {
		D3D11_TEXTURE2D_DESC desc{};
		tex2D->GetDesc(&desc);
		texWidth = desc.Width;
		texHeight = desc.Height;
	}
}

if (!texWidth || !texHeight) {
	logger::warn("[RCAS] Failed to resolve input texture dimensions, skipping sharpen");
	state->EndPerfEvent();
	return;
}

uint32_t dispatchX = (texWidth + 7) / 8;
uint32_t dispatchY = (texHeight + 7) / 8;

This keeps RCAS aligned with the actual resource size, independent of screenSize.

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• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl (1 hunks)
• src/Features/Upscaling.cpp (5 hunks)
• src/Features/Upscaling.h (4 hunks)
• src/Features/Upscaling/RCAS/RCAS.cpp (1 hunks)
• src/Features/Upscaling/RCAS/RCAS.h (1 hunks)
• src/Features/Upscaling/Streamline.cpp (1 hunks)
• src/Features/Upscaling/Streamline.h (0 hunks)

💤 Files with no reviewable changes (1)

• src/Features/Upscaling/Streamline.h

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🧠 Learnings (8)

📓 Common learnings

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 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
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:515-515
Timestamp: 2025-10-02T14:20:33.454Z
Learning: In the Community Shaders codebase (skyrim-community-shaders repository), hardcoded shader resource slot numbers are used directly in code rather than being defined as named constants. This is the established convention and should not be flagged as an issue.

📚 Learning: 2025-06-17T05:40:22.785Z

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 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/Features/Upscaling.h

📚 Learning: 2025-08-03T18:37:19.690Z

Learnt from: jiayev
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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/Features/Upscaling.h
• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl
• src/Features/Upscaling/Streamline.cpp

📚 Learning: 2025-08-17T18:37:35.839Z

Learnt from: CR
Repo: doodlum/skyrim-community-shaders PR: 0
File: .github/copilot-instructions.md:0-0
Timestamp: 2025-08-17T18:37:35.839Z
Learning: Applies to features/*/Shaders/**/*.{hlsl,hlsli,fx,fxh} : Avoid GPU register/buffer conflicts in HLSL; verify register usage (e.g., with hlslkit buffer scanning)

Applied to files:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl

📚 Learning: 2025-10-02T14:20:33.454Z

Learnt from: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:515-515
Timestamp: 2025-10-02T14:20:33.454Z
Learning: In the Community Shaders codebase (skyrim-community-shaders repository), hardcoded shader resource slot numbers are used directly in code rather than being defined as named constants. This is the established convention and should not be flagged as an issue.

Applied to files:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl

📚 Learning: 2025-08-05T18:22:40.578Z

Learnt from: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:277-293
Timestamp: 2025-08-05T18:22:40.578Z
Learning: In the skyrim-community-shaders SnowCover feature, the wstrtostr and strtowstr utility functions defined in src/Features/SnowCover.cpp are unused and should be removed rather than fixed, as confirmed by the original author ThePagi.

Applied to files:

• src/Features/Upscaling/Streamline.cpp

📚 Learning: 2025-06-17T09:27:49.594Z

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 1157
File: src/Feature.cpp:42-49
Timestamp: 2025-06-17T09:27:49.594Z
Learning: In src/Feature.cpp, when an obsolete feature's INI file is deleted, the feature should be silently disabled without surfacing any issues to the user. This is the intended behavior because a deleted INI file for an obsolete feature indicates that the user has properly cleaned up the obsolete feature.

Applied to files:

• src/Features/Upscaling/Streamline.cpp

📚 Learning: 2025-08-17T18:37:35.839Z

Learnt from: CR
Repo: doodlum/skyrim-community-shaders PR: 0
File: .github/copilot-instructions.md:0-0
Timestamp: 2025-08-17T18:37:35.839Z
Learning: Applies to features/**/*.{cpp,cxx,cc,h,hpp,hxx} : Register new features in the globals::features namespace

Applied to files:

• src/Features/Upscaling/Streamline.cpp

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🔇 Additional comments (2)

src/Features/Upscaling/Streamline.cpp (1)

105-106: NIS removal from Streamline feature list looks correct

Restricting featuresToLoad/featuresToLoadVR to sl::kFeatureDLSS cleanly drops NIS while keeping the feature count logic intact. No issues from this change in this file.

src/Features/Upscaling.cpp (1)

500-518: DLSS temp sharpener texture creation/destruction is consistent

The new sharpenerTexture:

• Is created only when a_upscalemethod == UpscaleMethod::kDLSS, using the kMAIN texture’s desc and explicit 2D SRV/UAV views (mip 0, single level), and
• Is freed when switching away from DLSS (a_upscalemethod != UpscaleMethod::kDLSS) alongside motionVectorCopyTexture.

This ties the resource lifetime correctly to DLSS usage and avoids leaving extra UAV/SRV views alive when DLSS is disabled. No issues here.

Also applies to: 558-565

[github-actions]

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Actionable comments posted: 0

🧹 Nitpick comments (1)

features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl (1)

27-35: Optional: Remove redundant clamp at line 31.

After the bounds check at lines 24-25, center is guaranteed to be within [0, texDim-1], making the clamp at line 31 redundant. The neighbor coordinate clamping (lines 32-35) is necessary and correct for edge handling.

Apply this diff to simplify:

 	int2 center = int2(DTid.xy);
 	int2 minCoord = int2(0, 0);
 	int2 maxCoord = int2(texDim - 1);
 
-	int2 eCoord = clamp(center, minCoord, maxCoord);
-	int2 bCoord = clamp(eCoord + int2(0, -1), minCoord, maxCoord);
-	int2 dCoord = clamp(eCoord + int2(-1, 0), minCoord, maxCoord);
-	int2 fCoord = clamp(eCoord + int2(1, 0), minCoord, maxCoord);
-	int2 hCoord = clamp(eCoord + int2(0, 1), minCoord, maxCoord);
+	int2 bCoord = clamp(center + int2(0, -1), minCoord, maxCoord);
+	int2 dCoord = clamp(center + int2(-1, 0), minCoord, maxCoord);
+	int2 fCoord = clamp(center + int2(1, 0), minCoord, maxCoord);
+	int2 hCoord = clamp(center + int2(0, 1), minCoord, maxCoord);
 
-	float3 e = Source.Load(int3(eCoord, 0)).rgb;
+	float3 e = Source.Load(int3(center, 0)).rgb;

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🧠 Learnings (4)

📓 Common learnings

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 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
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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.

📚 Learning: 2025-08-03T18:37:19.690Z

Learnt from: jiayev
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl

📚 Learning: 2025-08-17T18:37:35.839Z

Learnt from: CR
Repo: doodlum/skyrim-community-shaders PR: 0
File: .github/copilot-instructions.md:0-0
Timestamp: 2025-08-17T18:37:35.839Z
Learning: Applies to features/*/Shaders/**/*.{hlsl,hlsli,fx,fxh} : Avoid GPU register/buffer conflicts in HLSL; verify register usage (e.g., with hlslkit buffer scanning)

Applied to files:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl

📚 Learning: 2025-10-02T14:20:33.454Z

Learnt from: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:515-515
Timestamp: 2025-10-02T14:20:33.454Z
Learning: In the Community Shaders codebase (skyrim-community-shaders repository), hardcoded shader resource slot numbers are used directly in code rather than being defined as named constants. This is the established convention and should not be flagged as an issue.

Applied to files:

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

🔇 Additional comments (9)

features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl (9)

1-4: LGTM! Clear attribution to the FSR1 algorithm.

Proper licensing and source attribution are provided.

---

5-9: LGTM! Constant buffer properly aligned.

The float3 padding ensures the constant buffer meets the 16-byte alignment requirement.

---

14-17: LGTM! Custom luma weights are intentional for RCAS.

The weights (0.5, 1.0, 0.5) differ from perceptual luma because RCAS uses this for contrast-based edge detection rather than perceived brightness. This aligns with the AMD FSR1 reference implementation.

---

21-25: LGTM! Bounds check prevents out-of-bounds UAV writes.

The early exit for out-of-range thread IDs addresses the previous review's concern about undefined behavior when writing outside texture bounds. This ensures robust behavior across drivers.

---

37-42: LGTM! Sampling pattern is correct and safe.

The 4-neighbor cross pattern with clamped coordinates ensures safe edge handling. Extracting .rgb is appropriate for the RCAS algorithm.

---

44-54: LGTM! Noise detection follows FSR1's algorithm.

The noise factor nz correctly identifies flat/noisy regions to reduce sharpening artifacts. The non-linear correction at line 54 maps the normalized difference to [0.5, 1.0] for adaptive dampening.

---

56-68: LGTM! Lobe calculation matches FSR1's RCAS kernel.

The sharpening kernel correctly computes adaptive sharpening strength based on local min/max, applies the -0.1875 clamp per FSR1's specification, and modulates by both the sharpness parameter and the noise factor nz.

---

11-12: The register slot assignments (t0 for source texture, u0 for destination) follow established convention in the Community Shaders codebase and do not require verification as potential issues. Hardcoded shader resource slot numbers are the standard practice in this project.

---

69-72: Verify alpha channel and color space handling in RCAS shader.

1. Alpha channel: Confirm whether hardcoded 1.0 alpha in the output is intentional for the Upscaling pipeline's blend/composite stages, or if source alpha should be preserved.

2. Color space: Verify that the input to RCAS is in the appropriate color space for this implementation. Given the project uses a linear lighting system (per learnings), confirm whether gamma conversion is handled upstream/downstream or if RCAS should operate on linear values.

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (2)

features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl (1)

72-75: Consider preserving source alpha instead of forcing 1.0 if alpha carries meaning

Right now the shader hardcodes alpha = 1.0:

Dest[DTid.xy] = float4(output, 1.0);

If the main render target’s alpha is unused, this is fine. If alpha carries data (e.g. UI mask, exposure, or temporal weight), you may want to preserve it instead, e.g. by sampling the full center texel once and reusing its .a:

float4 eSample = Source.Load(int3(center, 0));
float3 e = eSample.rgb;
// ...
Dest[DTid.xy] = float4(output, eSample.a);

If alpha is guaranteed “don’t care” in this path, keeping 1.0 is acceptable.

src/Features/Upscaling/RCAS/RCAS.h (1)

18-42: Clarify destructor/ownership for rcasConfigCB and consider making RCAS non‑copyable

~RCAS() is declared but the header doesn’t show how rcasConfigCB is owned. With a raw ConstantBuffer* plus a non‑trivial destructor, copying RCAS would produce multiple instances pointing at the same buffer and can lead to leaks or double frees depending on how the destructor is implemented.

Recommendations:

• Ensure ~RCAS() is defined in RCAS.cpp and clearly manages rcasConfigCB (either releasing it if owned, or leaving it alone if it’s managed elsewhere).
• If RCAS owns its resources (likely, given Initialize()/CreateComputeShader()), explicitly delete copy/move operations or store the constant buffer in an owning smart pointer/RAII wrapper instead of a raw pointer, e.g. std::unique_ptr<ConstantBuffer> or a project‑specific handle type.
• Keep Initialize()’s “safe to call multiple times” guarantee by guarding against re‑creating the compute shader/CB if they’re already initialized.

These changes make the lifetime semantics explicit and prevent subtle resource bugs in the plugin runtime. As per coding guidelines around robust resource management.

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📥 Commits

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📒 Files selected for processing (4)

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl (1 hunks)
• src/Features/Upscaling.h (4 hunks)
• src/Features/Upscaling/RCAS/RCAS.cpp (1 hunks)
• src/Features/Upscaling/RCAS/RCAS.h (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (2)

• src/Features/Upscaling.h
• src/Features/Upscaling/RCAS/RCAS.cpp

🧰 Additional context used

📓 Path-based instructions (4)

**/*.{cpp,cxx,cc,c,h,hpp,hxx,hlsl,hlsli,fx,fxh,py}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Do not include TODO/FIXME placeholders; provide complete, working solutions

Files:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl
• src/Features/Upscaling/RCAS/RCAS.h

features/*/Shaders/**/*.{hlsl,hlsli,fx,fxh}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

features/*/Shaders/**/*.{hlsl,hlsli,fx,fxh}: Place all feature shaders under features/YourFeature/Shaders/
Avoid GPU register/buffer conflicts in HLSL; verify register usage (e.g., with hlslkit buffer scanning)

Files:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl

**/*

⚙️ CodeRabbit configuration file

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1. Conventional Commit Titles (if not following https://www.conventionalcommits.org/ or
   if the existing title does not describe the code changes):
   Format: type(scope): description
   Length: 50 characters limit for title, 72 for body
   Style: lowercase description, no ending period
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2. Issue References (if PR fixes bugs or implements features):
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Files:

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src/**/*.{cpp,cxx,cc,h,hpp,hxx}

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src/**/*.{cpp,cxx,cc,h,hpp,hxx}: Ensure SE/AE/VR runtime compatibility; use runtime detection patterns (e.g., REL::RelocateMember())
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Files:

• src/Features/Upscaling/RCAS/RCAS.h

🧠 Learnings (3)

📓 Common learnings

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 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
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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.

📚 Learning: 2025-08-03T18:37:19.690Z

Learnt from: jiayev
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl

📚 Learning: 2025-08-17T18:37:35.839Z

Learnt from: CR
Repo: doodlum/skyrim-community-shaders PR: 0
File: .github/copilot-instructions.md:0-0
Timestamp: 2025-08-17T18:37:35.839Z
Learning: Applies to features/*/Shaders/**/*.{hlsl,hlsli,fx,fxh} : Avoid GPU register/buffer conflicts in HLSL; verify register usage (e.g., with hlslkit buffer scanning)

Applied to files:

• features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl

🔇 Additional comments (4)

features/Upscaling/Shaders/Upscaling/RCAS/RCAS.hlsl (3)

8-21: RCAS constant buffer layout and luma helper look good, but confirm host-side struct matches

RCASConfig is a clean 16-byte cbuffer (float + float3) and getRCASLuma’s green‑weighted dot is reasonable for RCAS‑style luma. Just make sure the C++ side uses the same layout/order (e.g. struct RCASConfig { float sharpness; float pad[3]; };) and binds it to b0 alongside Source/Dest at t0/u0, otherwise sharpness will read garbage. Also, since this pass is explicitly “in HDR space before tonemapping”, double‑check that Source is indeed linear HDR and not gamma‑encoded, to avoid sharpening in the wrong color space. As per coding guidelines / learnings about linear color handling.

---

23-46: Bounds check + clamped neighbor sampling correctly avoid OOB access

Using Dest.GetDimensions, early‑out for DTid outside the surface, and clamping neighbor coordinates into [0, texDim-1] gives well‑defined behavior at image borders for both Source.Load and Dest[...] writes. This addresses the prior OOB risk for the right/bottom edges while keeping a sensible edge‑clamp kernel.

---

53-67: Add small epsilons around range and maxRGB to avoid potential INF/NaN in flat regions

In flat or near‑flat regions it's possible for range to become 0 and maxRGB to be all‑black, leading to rcp(0) which can propagate INF/NaN into the output. AMD's official RCAS reference implementation uses denominator clamping to address this. Consider adding epsilon guards:

range = max(range, 1e-4);
float3 safeMaxRGB = max(maxRGB, float3(1e-4, 1e-4, 1e-4));
float3 hitMin = minRGB * rcp(4.0 * safeMaxRGB);

Verify against the AMD FidelityFX FSR reference implementation for exact epsilon values and behavior compatibility.

src/Features/Upscaling/RCAS/RCAS.h (1)

9-16: RCAS API surface and documentation are clear and match the intended HDR DLSS sharpening use

The class comment and ApplySharpen doc make the role of RCAS in the upscaling pipeline very clear (standalone HDR‑space sharpening before tonemapping), and the small public surface (Initialize + ApplySharpen) is appropriate for this feature. The PR title fix(upscaling): replace NIS with RCAS for DLSS already follows Conventional Commits; in the PR description, consider adding a closing keyword like Fixes #1616 so GitHub auto‑closes the referenced issue when this merges.

[midona-rhel]

I am not able to replicate the build error, is this something that just happens at times?

[davo0411]

looks good.

[doodlum]

Looks good just remember to do float currentSharpness = (-2.0f * settings.sharpness) + 2.0f;

[midona-rhel]

Looks good just remember to do float currentSharpness = (-2.0f * settings.sharpness) + 2.0f;

Trying this breaks sharpening completely, 0->1 scaling works as intended in my subjective analysis. Any values with this formula below 0.5 creates artifacts or outright breaks the buffer

[coderabbitai]

Actionable comments posted: 1

📜 Review details

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Review profile: CHILL

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📥 Commits

Reviewing files that changed from the base of the PR and between d58794c and cfe6977.

📒 Files selected for processing (1)

• src/Features/Upscaling.cpp (6 hunks)

🧰 Additional context used

📓 Path-based instructions (3)

**/*.{cpp,cxx,cc,c,h,hpp,hxx,hlsl,hlsli,fx,fxh,py}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Do not include TODO/FIXME placeholders; provide complete, working solutions

Files:

• src/Features/Upscaling.cpp

src/**/*.{cpp,cxx,cc,h,hpp,hxx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

src/**/*.{cpp,cxx,cc,h,hpp,hxx}: Ensure SE/AE/VR runtime compatibility; use runtime detection patterns (e.g., REL::RelocateMember())
Include robust error handling and resource management with graceful degradation in the plugin code

Files:

• src/Features/Upscaling.cpp

**/*

⚙️ CodeRabbit configuration file

**/*: When reviewing PRs, please provide suggestions for:

1. Conventional Commit Titles (if not following https://www.conventionalcommits.org/ or
   if the existing title does not describe the code changes):
   Format: type(scope): description
   Length: 50 characters limit for title, 72 for body
   Style: lowercase description, no ending period
   Examples:

   • feat(vr): add cross-eye sampling
   • fix(water): resolve flowmap bug
   • docs: update shader documentation

2. Issue References (if PR fixes bugs or implements features):
   Suggest adding appropriate GitHub keywords:

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Files:

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🧠 Learnings (1)

📓 Common learnings

Learnt from: jiayev
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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
Repo: doodlum/skyrim-community-shaders PR: 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: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:260-260
Timestamp: 2025-08-05T18:13:03.123Z
Learning: In the skyrim-community-shaders SnowCover feature, the time calculation uses division by 61.0 instead of 60.0 for seconds conversion in the perFrame.Month calculation. The original author ThePagi indicated this was intentional and makes no discernible difference to the snow cover functionality, suggesting it may be related to game-specific timing mechanics or balance considerations.

Learnt from: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:515-515
Timestamp: 2025-10-02T14:20:33.454Z
Learning: In the Community Shaders codebase (skyrim-community-shaders repository), hardcoded shader resource slot numbers are used directly in code rather than being defined as named constants. This is the established convention and should not be flagged as an issue.

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

🔇 Additional comments (4)

src/Features/Upscaling.cpp (4)

500-519: LGTM! Proper RCAS sharpener texture setup.

The sharpener texture is correctly created with the main render target's format to preserve HDR data, and both SRV/UAV views are properly initialized for compute shader access.

---

559-566: LGTM! Proper resource cleanup.

The sharpener texture cleanup follows the established pattern and correctly releases COM resources before deletion.

---

891-891: LGTM! RCAS initialization properly placed.

The RCAS subsystem is initialized at the appropriate point in the resource setup flow.

---

1477-1478: LGTM! RCAS sharpening correctly integrated for DLSS.

The sharpening is applied at the right point in the rendering pipeline (after upscaling, before post-processing) and only for DLSS, which makes sense since FSR has built-in sharpening.

[coderabbitai]

⚠️ Potential issue | 🔴 Critical

Fix compilation error and remove dead code.

Lines 1430-1431 reference undefined settings.sharpness (should be settings.sharpnessDLSS) and calculate currentSharpness that is never used. Based on the PR comments, this appears to be leftover code from an attempted formula that broke sharpening.

Apply this diff to remove the dead code and fix the compilation error:

 void Upscaling::ApplySharpening()
 {
 	if (settings.sharpnessDLSS <= 0.0f)
 		return;
 
 	if (!sharpenerTexture)
 		return;
-	float currentSharpness = (-2.0f * settings.sharpness) + 2.0f;
-	currentSharpness = exp2(-currentSharpness);
 
 	auto context = globals::d3d::context;
 	auto renderer = globals::game::renderer;
 	auto& main = renderer->GetRuntimeData().renderTargets[RE::RENDER_TARGETS::kMAIN];
 
 	ID3D11Resource* mainResource = nullptr;
 	main.SRV->GetResource(&mainResource);
 
 	if (!mainResource)
 		return;
 
 	context->OMSetRenderTargets(0, nullptr, nullptr);
 
 	rcas.ApplySharpen(main.SRV, sharpenerTexture->uav.get(), settings.sharpnessDLSS);
 	context->CopyResource(mainResource, sharpenerTexture->resource.get());
 
 	mainResource->Release();
 
 	globals::game::stateUpdateFlags->set(RE::BSGraphics::ShaderFlags::DIRTY_RENDERTARGET);
 }

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change

	void Upscaling::ApplySharpening()
	{
	if (!streamline.featureNIS || settings.sharpnessDLSS <= 0.0f) {
	if (settings.sharpnessDLSS <= 0.0f)
	return;
	}
	auto context = globals::d3d::context;
	ID3D11RenderTargetView* renderTarget = nullptr;
	context->OMGetRenderTargets(1, &renderTarget, nullptr);
	if (!sharpenerTexture)
	return;
	float currentSharpness = (-2.0f * settings.sharpness) + 2.0f;
	currentSharpness = exp2(-currentSharpness);
	winrt::com_ptr<ID3D11Resource> mainResource;
	renderTarget->GetResource(mainResource.put());
	auto context = globals::d3d::context;
	auto renderer = globals::game::renderer;
	auto& main = renderer->GetRuntimeData().renderTargets[RE::RENDER_TARGETS::kMAIN];
	context->OMSetRenderTargets(0, nullptr, nullptr); // Unbind all bound render targets
	ID3D11Resource* mainResource = nullptr;
	main.SRV->GetResource(&mainResource);
	context->CopyResource(nisSharpenerTexture->resource.get(), mainResource.get());
	if (!mainResource)
	return;
	streamline.ApplyNISSharpening(nisSharpenerTexture->resource.get(), settings.sharpnessDLSS);
	context->OMSetRenderTargets(0, nullptr, nullptr);
	context->CopyResource(mainResource.get(), nisSharpenerTexture->resource.get());
	rcas.ApplySharpen(main.SRV, sharpenerTexture->uav.get(), settings.sharpnessDLSS);
	context->CopyResource(mainResource, sharpenerTexture->resource.get());
	globals::game::stateUpdateFlags->set(RE::BSGraphics::ShaderFlags::DIRTY_RENDERTARGET); // Run OMSetRenderTargets again
	mainResource->Release();
	if (renderTarget)
	renderTarget->Release();
	globals::game::stateUpdateFlags->set(RE::BSGraphics::ShaderFlags::DIRTY_RENDERTARGET);
	}
	void Upscaling::ApplySharpening()
	{
	if (settings.sharpnessDLSS <= 0.0f)
	return;
	if (!sharpenerTexture)
	return;
	auto context = globals::d3d::context;
	auto renderer = globals::game::renderer;
	auto& main = renderer->GetRuntimeData().renderTargets[RE::RENDER_TARGETS::kMAIN];
	ID3D11Resource* mainResource = nullptr;
	main.SRV->GetResource(&mainResource);
	if (!mainResource)
	return;
	context->OMSetRenderTargets(0, nullptr, nullptr);
	rcas.ApplySharpen(main.SRV, sharpenerTexture->uav.get(), settings.sharpnessDLSS);
	context->CopyResource(mainResource, sharpenerTexture->resource.get());
	mainResource->Release();
	globals::game::stateUpdateFlags->set(RE::BSGraphics::ShaderFlags::DIRTY_RENDERTARGET);
	}

🤖 Prompt for AI Agents

In src/Features/Upscaling.cpp around lines 1423-1451, lines 1430-1431 reference
an undefined settings.sharpness and compute a currentSharpness value that is
never used; remove those two lines (the assignment to currentSharpness and the
exp2 call) so the code uses only settings.sharpnessDLSS and eliminate the
dead/invalid code, then rebuild to confirm compilation succeeds.

[alandtse]

@midona-rhel the build error is complaining settings.sharpness doesn't exist. This comment specifically pointed out the issue. Please review all comments and verify.

[coderabbitai]

Seems like the humans are having a chat. I'll hop back into my burrow for now. If you need me again, just tag @coderabbitai in a new comment, and I'll come hopping out!

[alandtse]

@midona-rhel the build error is complaining settings.sharpness doesn't exist. This comment specifically pointed out the issue. Please review all comments and verify.

[midona-rhel]

Resolved now, pushed me just doing a dumb thing and didnt get around to it until now. Should work as advertised now

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (4)

src/Features/Upscaling.cpp (4)

500-519: RCAS sharpener texture lifetime wiring looks correct; minor optional mip-level tweak

Creation/destruction of sharpenerTexture is correctly tied to the DLSS path and cleaned up when switching away from DLSS, so resource lifetime looks sound. As an optional optimization, since you only ever use mip 0 in the SRV/UAV, you could set texDesc.MipLevels = 1 before constructing sharpenerTexture to avoid allocating unused mips and keep the descriptor and texture layout perfectly aligned, but the current code is functionally fine.

Also applies to: 559-566

---

889-897: Confirm rcas.Initialize() is safe to call more than once

SetupResources() can be invoked again on device loss / recreation or similar paths; please double‑check that RCAS::Initialize() is idempotent (or internally guarded) so repeated calls don’t leak resources or re-register states incorrectly. If it isn’t already, consider adding an internal “initialized” flag or similar guard inside RCAS rather than relying on external callers.

---

1423-1452: Revisit DLSS slider → RCAS sharpness mapping before finalizing

This now applies RCAS with currentSharpness derived from settings.sharpnessDLSS via (-2.0f * x + 2.0f) and exp2(-currentSharpness), instead of passing the raw 0–1 slider, and uses that as the RCAS parameter. That matches the formula requested in the PR discussion, but earlier comments also reported that this transform made sharpening behave incorrectly compared to a straight 0→1 mapping, especially for values that map below ~0.5. I’d suggest re-validating this in-game and against RCAS docs/samples; if the intended UX is “0 disables, 1 is strongest” with no non-linear scaling, you can drop the transform and pass settings.sharpnessDLSS directly (optionally clamped to a minimum value if very low RCAS parameters are known-bad). The rest of the path (null checks, temporary mainResource AddRef/Release, unbinding OM, using the UAV as output and copying back to main) looks correct.

---

1-1521: PR metadata: title looks good; consider adding an auto-closing issue reference

The current title fix(upscaling): replace NIS with RCAS for DLSS already follows Conventional Commits and clearly describes the change. Since this is intended to resolve Issue #1616, consider adding Fixes #1616 to the PR description so GitHub will auto-close the issue on merge, in line with the repository’s guidelines.

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🧠 Learnings (4)

📓 Common learnings

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 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
Repo: doodlum/skyrim-community-shaders PR: 0
File: :0-0
Timestamp: 2025-08-03T18:37:19.690Z
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: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:260-260
Timestamp: 2025-08-05T18:13:03.123Z
Learning: In the skyrim-community-shaders SnowCover feature, the time calculation uses division by 61.0 instead of 60.0 for seconds conversion in the perFrame.Month calculation. The original author ThePagi indicated this was intentional and makes no discernible difference to the snow cover functionality, suggesting it may be related to game-specific timing mechanics or balance considerations.

Learnt from: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:515-515
Timestamp: 2025-10-02T14:20:33.454Z
Learning: In the Community Shaders codebase (skyrim-community-shaders repository), hardcoded shader resource slot numbers are used directly in code rather than being defined as named constants. This is the established convention and should not be flagged as an issue.

📚 Learning: 2025-07-05T05:20:45.823Z

Learnt from: alandtse
Repo: doodlum/skyrim-community-shaders PR: 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/Features/Upscaling.cpp

📚 Learning: 2025-08-05T17:40:44.828Z

Learnt from: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: package/Shaders/Lighting.hlsl:0-0
Timestamp: 2025-08-05T17:40:44.828Z
Learning: In the skyrim-community-shaders repository, ultra trees (object LOD trees) are detected using a compound shader define condition `defined(DO_ALPHA_TEST) && defined(LOD_BLENDING) && defined(RIM_LIGHTING) && defined(SOFT_LIGHTING)` because "they have no define" according to the comment. The `ExtraFlags::IsTree` flag is used for different tree handling (AO removal in skylighting) and may not apply to ultra trees specifically. Before replacing the compound condition with `IsTree`, verification is needed to ensure the flag covers ultra trees.

Applied to files:

• src/Features/Upscaling.cpp

📚 Learning: 2025-08-05T18:22:40.578Z

Learnt from: ThePagi
Repo: doodlum/skyrim-community-shaders PR: 1369
File: src/Features/SnowCover.cpp:277-293
Timestamp: 2025-08-05T18:22:40.578Z
Learning: In the skyrim-community-shaders SnowCover feature, the wstrtostr and strtowstr utility functions defined in src/Features/SnowCover.cpp are unused and should be removed rather than fixed, as confirmed by the original author ThePagi.

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• src/Features/Upscaling.cpp

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🔇 Additional comments (1)

src/Features/Upscaling.cpp (1)

1478-1479: DLSS-only RCAS sharpening call is appropriately gated

Conditioning ApplySharpening() on upscaleMethod == UpscaleMethod::kDLSS ensures RCAS is only run when the DLSS pipeline and its associated resources (including sharpenerTexture) are active, while FSR continues to use its own sharpening path. This matches the PR’s intent of replacing NIS specifically for DLSS without impacting other modes.

fixed