RTXGI: Scalable Ray Traced Global Illumination in Real Time

Abstract

In this talk, we will discuss how you can achieve multi-bounce ray traced diffuse global illumination in real time with the new RTX Global Illumination (RTXGI) SDK. RTXGI fits into the modern game engine by directly replacing existing indirect lighting approaches such as screen-space ray casting, precomputed lightmaps, and baked irradiance probes. We combine ray tracing, fast irradiance updates, and a moment-based depth scheme for occlusion calculations to create a scalable system without bake times or light leaks. RTXGI is supported on any DXR-enabled GPU and provides developers with an ideal starting point to bring the benefits of real-time ray tracing to their existing tools, knowledge, and capabilities.