feat(rtx): add maxSampledLights to Interactive renderer#340
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jeffamstutz merged 1 commit intoJul 15, 2026
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Interactive summed direct lighting over ALL light instances per hit (one shadow ray each), so many-light scenes were O(N) and slow. Add a maxSampledLights renderer param (uint, default 8, <=0 = all): when the scene has more light instances than the cap, importance-sample that many via the world Pick-Power CDF and reweight by 1/(K*pPick) instead of looping all of them. E[stochastic] == the all-lights sum, so the accumulated image converges; small scenes keep the exact deterministic loop. HDRI MIS is unchanged (escape side stays deterministic, so pLight=envPdf with the reweight is MIS-consistent). Uniform-pick fallback when total Pick Power is zero.
jeffamstutz
approved these changes
Jul 15, 2026
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Interactive summed direct lighting over ALL light instances per hit (one shadow ray each), so many-light scenes were O(N) and slow.
Add a
maxSampledLightsrenderer param (int, default 8, <=0 => all): when the scene has more light instances than the cap, importance-sample that many via the world Pick-Power CDF instead of looping all of them.This gives back performances and predictability on low lights count scenes -- more common sci-viz case -- while preserving correctness on many lights scenes, still at the expense of more convergences frames.