Implementation of global illumination using on-surface caches

Real-time path-tracing remains limited by the high computational cost of evaluating lighting through per-pixel Monte Carlo integration. This inhibits imagery generated using stochastic path-tracing approaches from replacing rasterization-based or simpler hybrid approaches in real-time renderers. This thesis addresses these inefficiencies by investigating the utilization of radiance caching, and in particular, in texture space, which replaces deep per-ray evaluations with cheap cache look-ups and illumination smoothing via trilinear interpolation performed directly on object surfaces. We directly implement On-Surface Caching for Global illumination (OSC-GI) [Tat+24] and attempt to verify the writers’ findings. Ray-casting is decoupled from the screen-space sampling rate and its results are instead stored on sparser, spatio-temporally stable on-surface cache blocks that pixels query during shading. This decoupling also allows for the sharing of radiance over multiple cameras, effectively accelerating multi-view rendering. We leverage OSC-GI’s two-level radiance caching scheme and achieve real-time global illumination for diffuse and glossy surfaces by using the secondary cache level to represent the indirect radiance field that the primary cache samples.