Dynamic Diffuse Global Illumination Resampling

Ray traced global illumination can be partitioned into direct contributions of the light sources that reflect to the camera after one bounce and indirect contributions that scatter for multiple bounces. We propose a new real-time solution called dynamic diffuse global illumination resampling that computes direct and indirect illumination accurately and with low noise. The key idea is to derive a new, unified algorithm from the principles of the state of the art ReSTIR many-lights direct shadowing [Bitterli et al. 2020] and the DDGI indirect light probes [Majercik et al. 2019] real-time algorithms. By this unification, global illumination resampling achieves higher quality than the combination of its two components at real-time framerates. At the cost of little bias, our technique also outperforms hardware accelerated path tracing in both runtime and noise.