GI hits: opaque-only sun visibility (up to 3 rays per lit hit today) #981

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opened 2026-10-23 18:07:41 +00:00 by sky_line · 1 comment

sky_line commented

2026-10-23 18:07:41 +00:00

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A sunlit GI hit can cast up to 3 rays for sun visibility: the disc split, then the translucent walk, then the foliage transmittance. An opaque-only sun rule at GI hits would save about 0.5-1 ms.

Visual cost: no coloured light through glass or leaves in bounced light. Small effort.

From the 2026-10-23 GI performance pass. Baseline: RTX 5090, 4K, DLSS Ultra Performance (1280x720 render), GI at full render resolution, GI 3 + cache, ReSTIR DI 3, emissive on: GPU 30.9 ms/frame (GPU-bound), async deferred lighting 20.1 ms, `c_gi_trace` 12.7 ms (883k rays/frame). A sunlit GI hit can cast up to 3 rays for sun visibility: the disc split, then the translucent walk, then the foliage transmittance. An opaque-only sun rule at GI hits would save about 0.5-1 ms. Visual cost: no coloured light through glass or leaves in bounced light. Small effort.

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2026-10-23 18:07:41 +00:00

sky_line added this to the Slipstream project

2026-10-23 18:07:42 +00:00

sky_line referenced this issue

2026-10-25 03:19:37 +00:00

[Epic] Shared ray-traced visibility pass (ray queue) for shadows, GI, reflections and lit shaders #1039

sky_line commented

2026-10-25 03:19:37 +00:00