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Q&A: How Capcom Brought Path Tracing to RE ENGINE Across PRAGMATA and Resident Evil Requiem
NVIDIA Developer BlogMichelle Horton
Summary
Capcom integrated path tracing into RE ENGINE across PRAGMATA and Resident Evil Requiem to deliver unified indirect and direct lighting. Over two years, the team built a reference path tracer validated against standard DCC tools, scaling it down into a real-time version optimized for NVIDIA DLSS Ray Reconstruction denoising. To manage rendering performance, Capcom avoided expensive AlphaTest texture lookups by creating a ScreenSpaceAlphaTest method comparing ray-hit positions against screen-space depth. Sampling noise in emissive and indoor regions is mitigated using Next Event Estimation and a custom implementation of ReSTIR GI. Replacing traditional shadow maps with continuous path tracing reduced the visual gap between gameplay and cinematics while enabling real-time light transmission through strand hair.
Context
Capcom sought to move beyond ray-traced indirect lighting and shadow maps in RE ENGINE for PRAGMATA and Resident Evil Requiem, aiming to naturally integrate reflections and direct and indirect illumination across entire game environments without per-scene manual tuning.
Approach / What changed
Capcom built a reference path tracer validated against DCC path tracers, then produced a real-time game path tracer using the NVIDIA RTX Kit and DLSS Ray Reconstruction. The team implemented Next Event Estimation for emissive samples, a custom ReSTIR GI implementation for indoor lighting, and a ScreenSpaceAlphaTest method comparing ray-hit positions with screen-space depth.
Takeaways
- Capcom created a lightweight ScreenSpaceAlphaTest method that evaluates ray-hit positions against screen-space depth to avoid costly texture lookups on cutout geometry.
- To reduce sampling noise in emissive and indoor scenes, RE ENGINE utilizes Next Event Estimation alongside a custom in-engine implementation of ReSTIR GI based on the published paper.
- Applying path tracing to direct lighting eliminated the resolution limits of shadow maps, significantly reducing the visual disparity between cutscenes and real-time gameplay.
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