Interactive, Multiresolution Image-Space Rendering for Dynamic Area Lighting

Area lights add tremendous realism, but rendering them interactively proves challenging. Integrating visibility is costly, even with current shadowing techniques, and existing methods frequently ignore illumination variations at unoccluded points due to changing radiance over the light’s surface. We extend recent image-space work that reduces costs by gathering illumination in a multiresolution fashion, rendering varying frequencies at corresponding resolutions. To compute visibility, we eschew shadow maps and instead rely on a coarse screen-space voxelization, which effectively provides a cheap layered depth image for binary visibility queries via ray marching. Our technique requires no precomputation and runs at interactive rates, allowing scenes with large area lights, including dynamic content such as video screens. Figure 1: Traditional real time renderers (a) allow only point lighting. We introduce a multiresolution image-space approach (b) that enables illumination from dynamic area lights. No precomputation is needed, so we handle dynamic geometry (c). The image-space computations decouple algorithmic and geometric complexity, so scenes with hundreds of thousands of polygons (d) still render interactively.