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.

Rendering soft shadows cast by dynamic objects in real-time with few visual artifacts is challenging to achieve. We introduce a new algorithm for local light sources that exhibits fewer artifacts than fast single-view approximations, and is faster than high quality multi-view solutions. Inspired by layered depth images, image warping, and point-based rendering, our algorithm traverses complex occluder geometry once and creates an optimized multi-view point cloud as a proxy. We then render many depth maps simultaneously on graphics hardware using GPU Compute. By significantly reducing the time spent producing depth maps, our solution presents a new alternative for applications that cannot yet afford the most accurate methods, but strive for higher quality shadows than possible with common approximations.

We discuss a pragmatic approach to real-time supersampling that extends common temporal antialiasing techniques with adaptive ray tracing. We have integrated our solution into Unreal Engine 4, and demonstrate how it removes the blurring and ghosting artifacts associated with standard temporal antialiasing, achieves quality approaching 16x supersampling, and operates within a 16ms frame budget.