Dynamic ambient occlusion from volumetric proxies

Real-time applications require simple techniques that enable predictable high performance rendering, but illumination methods for GPUs tend either to be complex and fragile on the one hand or very limited and offering poor visual quality on the other. The addition of a plausible global look to an application's lighting impacts users' perceptions of its realism, and on the spectrum of existing approaches, screen space ambient occlusion (SSAO) lies at the simplest and most predictable end. We have extended screen space ambient occlusion by replacing its depth buffer comparisons with a sampling of a volumetric discretization of the scene, while still evaluating it in an image-space post-process and thus retaining its predictable performance. We show improvements in quality over depth buffer based alternatives at a reasonable additional cost.