DUDE 0.9.6

DUDE 0.9.6 — the Path Tracing tier

A ray-tracing improvement release on top of 0.9.5.
0.9.5 was about speed; 0.9.6 is about the light. The top Vulkan tier is now a full ray-traced Path Tracing path: direct lighting is sampled and denoised with ReSTIR instead of rasterised; a ReGIR light grid and a multi-bounce irradiance cache make that affordable, and the whole stack has been retuned updating the presets so the nightmare path traced should roughly run at 60FPS on a RTX 3080 card at 1440p.

Changed since 0.9.5

Ray-traced direct lighting — the new Path Tracing tier

• ReSTIR direct illumination. At the Path Tracing tier (Vulkan, top dude_rtx setting) the scene's lights are sampled as area lights through reservoir resampling (ReSTIR DI) and denoised with NRD ReLAX, replacing the rasterised light loop. Soft, correct direct shadows and per-light shading, with the lights that are actually visible in the frame always entering the sample set.
• ReGIR light grid (r_rtLightGrid*): a world-space grid builds a small per-cell importance set of lights each frame, so the DI gather samples a handful of relevant lights per pixel instead of the whole scene — the single biggest cost cut on the tier (gather time ≈ −68%). Looked up with a per-pixel half-cell jitter to hide the grid, and ranked by each light's own falloff.
• Multi-bounce irradiance cache: a hashed world-space cache stores bounce irradiance and feeds additional light bounces back into the gather (and serves the GI path tail), so light carries further through a scene for little extra cost. History and resets are tracked in time, not frames, and cells reset only when the DI gradient says the light really changed - flickering lights blend instead of restarting.
• SH bump detail (r_rtReStirDISH, on at the tier): the denoised direct light is re-modulated per texel against the surface bump/normal, bringing back the fine relief that a reduced-resolution denoised buffer would otherwise flatten.
• Material fidelity in the gather: skin and flesh get subsurface warmth at the terminator, a full-resolution specular re-shade sharpens highlights, death-fade crossfades blend instead of popping to black, and surfaces with no diffuse stage read black (not white) albedo. Decals no longer pick up a direct-light glint, and per-stage vertex colour is honoured for terrain blends.

Ray-traced GI, AO and shadows

• GI bounce sampling moved to an R2 low-discrepancy sequence, replacing the interleaved gradient noise whose 45° lattice streaked diagonally through the denoiser. RTAO got the same treatment. Cleaner GI and AO with no extra cost.
• RT shadows now scale from Medium up to Nightmare instead of only the top tier, and the soft grate shadows take the shape of the shadow-map caster (no more cage-sphere approximation) and soften under the same blur law as the rest of the RT shadows. RT shadow-blur intensity and falloff were retuned softer.
• Irradiance cache and eye adaptation enable wherever RTGI runs; the cache path tail stays Path-Tracing-only.

A retuned, hand-balanced baseline

• The ReSTIR DI, RTGI, light-grid, irradiance-cache, RTAO and RT-shadow defaults were all rebaked from my own dialed-in configuration — the cache/quality/frame-time balance that the Path Tracing tier actually ships at. Fresh installs now start from that balance rather than the raw code defaults. The quality presets still own the per-tier enables and resolutions; only the preset-independent "free knobs" were moved.
• The DI debug / tuning surface in the in-game menu was reorganised into clear groups with every ReLAX and GI denoiser knob exposed, and Film Grain got its own labelled switch + knob block.

Load time

• Level sounds now decode in parallel across the image/worker threads instead of synchronously inside material parsing — another cut to cold level-load time, on every backend.

Fixes

• The monster spawn-in flash is toned down and reddened (it was a blinding white pop), in both Doom 3 and Resurrection of Evil.
• AO bake: eyewear is excluded from the bake and refused at runtime, and translucent surfaces no longer occlude the bake.
• GPU skinning: the seam weld is decoupled from lighting (crack-free and cut-free), with a toggle in the GPU Offload settings group.

Emissive Mode — experimental, shipping OFF (incomplete)

0.9.6 includes a large amount of in-progress work on an Emissive Mode for the Path Tracing tier - a system that turns a level's self-illuminated surfaces (light fixtures, screens, glowing materials) into real emitters that light the scene directly, with a per-material emitter table and an in-game emitter editor. This feature is not finished and ships disabled by default. It
is not wired into any quality preset and is gated behind its own cvars ("r_rtEmissiveLighting", "r_rtEmissiveTable", "r_rtEmissivePhysical"); leave them off for the intended 0.9.6 experience. It is included only so the work is in the open — treat it as a preview that may change or break, not a supported feature.

Performance notes

The Path Tracing tier is demanding — it is a full ray-traced lighting path. Use it on a capable Vulkan GPU, and lean on FSR2 sub-native upscaling (Graphics → Upscaling, from 0.9.5) and the per-tier resolution/checkerboard controls to hit your frame-time budget. The ReGIR light grid and the irradiance cache are what make the tier playable; both are on automatically at the tier. Measure on your own GPU with the in-game benchmark ("com_timeDemoRealTime 1" then "timeDemo demo1").

Known limitations

• The Path Tracing tier — ReSTIR DI, the ReGIR light grid, the irradiance cache and the SH bump detail — is Vulkan-only. The OpenGL renderers get the load-time win and the spawn-flash and AO-bake fixes, but none of the ray-traced lighting.
• Emissive Mode is incomplete and ships off (see above).
• The retuned defaults only reach fresh installs or a graphics-config reset — an existing config keeps your current values. Delete your graphics settings (or use the in-game reset) to pick up the new baseline.

Setup notes (same as 0.9.5)

If the Vulkan renderer won't start (the OpenGL renderers are unaffected), update or reinstall your GPU driver - the Vulkan driver (the ICD the loader dispatches to) ships with it, and no bundled loader can substitute for a missing or Vulkan-incapable one. On Windows, "vulkan-1.dll" comes from your GPU driver; DUDE deliberately does not ship it. On Linux a current loader is bundled in lib/ as a fallback for old distro loaders, but it still needs your driver's ICD.

Optional download: baked ambient-occlusion pack

dude-0.9.6-baked-ao.zip: precomputed per-material AO maps for subtle contact shading on world surfaces, props and weapons. The world-surface pack was re-baked this release with the bake fixes above (translucent surfaces no longer occlude); the prop and weapon packs are unchanged from 0.9.5. Extract into your Doom 3 directory the same way. Entirely optional, and unused at the Path Tracing tier (ray-traced GI/AO replace it there).

DUDE is GPLv3 — source at https://github.com/Inkub0/dude.