Ambient Occlusion Using Cone Tracing with Scene Voxelization

Abstract

Ambient occlusion is a low-cost technique to simulate indirect ambient illumination in a realistic way. The goal is to estimate the amount of incident ambient light at each visible point. In this paper, we propose a novel ambient occlusion method that produces good quality results in real time. Using an efficient voxelization algorithm, we create a volumetric description of the scene geometry in a regular grid. During scene rendering, the hemisphere around each visible point is sampled by a set of cones, each one representing a package of rays. The volume of each cone is sampled by a series of spheres. The obstructed volumes of the spheres are used to estimate the amount of rays that are blocked by the scene geometry. The final ambient occlusion at each visible point is computed by considering all cones in the hemisphere. This approach has shown to be quite adequate: the intersection of each sphere with the voxelized scene is performed in a very efficient manner, and good quality results are achieved with a small number of cones. Computational experiments demonstrate the efficiency and effectiveness of our proposal.