Optional DLSS Ray Reconstruction

Japanese documentation: DLSS Ray Reconstruction

D3D12LookDevPTWinUI contains an optional Streamline/DLSS Ray Reconstruction backend. It dynamically loads Streamline, validates the adapter and driver, separates render and output resolutions, prepares the required guide resources, tags them for the current frame, and calls slEvaluateFeature on the renderer's D3D12 command list.

DLSS-RR remains independent of the RTX 4070 / 1080p60 ReSTIR GI+DI gate. Missing binaries, an unsupported adapter/driver, an absent application identity, or a runtime evaluation failure select native reconstruction without making Streamline a process-load dependency.

Dependencies And Application Identity

Pinned submodules:

• ThirdParty/Streamline: NVIDIA Streamline SDK v2.12.0
• ThirdParty/DLSS: NVIDIA DLSS SDK v310.7.0

Initialize them with:

git submodule update --init --recursive ThirdParty/Streamline ThirdParty/DLSS

The DLSS SDK supplies nvngx_dlss.dll and nvngx_dlssd.dll. A source-only Streamline checkout may not include all prebuilt runtime and feature DLLs. When present, the build copies these files to Bin/x64/<Config>/Streamline/:

sl.interposer.dll
sl.common.dll
sl.dlss.dll
sl.dlss_d.dll
nvngx_dlss.dll
nvngx_dlssd.dll

Production NGX components also require an application identity issued by NVIDIA. Keep the decimal ID outside source control and set it before launching:

$env:D3D12LOOKDEVPT_NGX_APPLICATION_ID = "<NVIDIA-issued decimal ID>"

The renderer does not substitute a temporary or invented application ID. Without this variable it reports applicationIdentityConfigured=false, identifies applicationIdentity as the failure stage, and uses native reconstruction.

The setup checker validates files; strict DLSS validation treats missing runtime DLLs as a failure:

.\Scripts\CheckSetup.ps1 -CheckDLSS

Build Switch And Matrix

DLSS header support is enabled by default:

msbuild .\D3D12LookDevPTWinUI.sln /m /p:Configuration=Release /p:Platform=x64

Disable it when validating the dependency-free path:

msbuild .\D3D12LookDevPTWinUI.sln /m /p:Configuration=Release /p:Platform=x64 /p:EnableDLSS=false

With EnableDLSS=false, no Streamline/DLSS include path or optional runtime copy is used, status reports compiled=false, and dlss_rr falls back to native internal reconstruction.

The backend matrix covers all-enabled, no-NRD, no-RTXDI, no-DLSS, all-disabled, and the repository target:

.\Scripts\BuildBackendMatrix.ps1 -Configuration Release

Frame Evaluation

Initialization performs the following:

1. load sl.interposer.dll and resolve the required core functions;
2. initialize Streamline for D3D12 with frame-based resource tagging;
3. register the D3D12 device;
4. validate the NVIDIA-issued application identity;
5. query kFeatureDLSS_RR support for the selected adapter/driver;
6. query the recommended render size and configure the selected DLSS mode.

For each eligible frame, PathTracingDlss.hlsl prepares:

• HDR scaling-input color;
• positive linear depth;
• 2D motion vectors;
• packed world normal and roughness;
• diffuse albedo and specular albedo;
• a 1x1 exposure resource.

The backend submits camera matrices, jitter, reset state, render/output extents, and the eight resource tags, then evaluates kFeatureDLSS_RR inside the active command list. A successful evaluation produces display-resolution HDR and bypasses NRD, the internal denoiser, and Final TAA before tone mapping.

If evaluation fails, its partial output is never displayed. The renderer performs native reconstruction for that frame, disables further evaluation, and requests native resource reconstruction for the following frame. Resize, camera cut, and explicit reset propagate a DLSS history reset.

Resolution And Runtime Status

The quality schema separates render and output resolution:

{
  "resolutionMode": "dynamic",
  "fixedRenderScale": 0.75,
  "minRenderScale": 0.5,
  "maxRenderScale": 1.0
}

resolutionMode accepts native, fixed, or dynamic; older projects default to native. Dynamic mode uses the existing GPU budget and settle hysteresis and adjusts in 1/16 increments. Native non-DLSS paths use TAAU when render and output sizes differ, while NRD runs at render resolution.

Select DLSS-RR through the Denoise panel or MCP:

{
  "method": "set_denoise",
  "params": {
    "backend": "dlss_rr",
    "dlssMode": "quality",
    "resetDlss": true
  }
}

Read denoise.dlss / denoiser.dlss from lookdevpt.get_state or lookdevpt.get_stats. Status includes compile/load/init/device/application-identity/support/evaluation state, recommended and active dimensions, successful/failed evaluation counts, last result code and failure stage, runtime path, error, and fallback reason. Benchmark output exposes the same activation and failure evidence.

Active DLSS-RR evaluation has not been certified in this checkout because the local environment does not contain an NVIDIA-issued NGX application ID. The missing-identity fallback has been exercised; feature-active validation still requires the issued ID, compatible GPU/driver, and production runtime DLLs.