Layered Reflective Shadow Maps for Voxel-based Indirect Illumination

Abstract

We introduce a novel voxel-based algorithm that interactively simulates both diffuse and glossy single-bounce indirect illumination. Our algorithm generates high quality images similar to the reference solution while using only a fraction of the memory of previous methods. The key idea in our work is to decouple occlusion data, stored in voxels, from lighting and geometric data, encoded in a new per-light data structure called layered reflective shadow maps (LRSMs). We use voxel cone tracing for visibility determination and integrate outgoing radiance by performing lookups in a pre-filtered LRSM. Finally we demonstrate that our simple data structures are easy to implement and can be rebuilt every frame to support both dynamic lights and scenes.