Colom, ArnauMarques, RicardoSantos, Luís PauloLiu, LingjieAverkiou, Melinos2024-04-302024-04-302024978-3-03868-239-41017-4656https://doi.org/10.2312/egp.20241043https://diglib.eg.org/handle/10.2312/egp20241043Physically-based synthesis of high quality imagery results in a significant workload, which makes interactive rendering a very challenging task. Our approach to achieve such interactive frame rates while accurately simulating global illumination phenomena entails developing a Virtual Point Lights (VPL) ray tracer that runs entirely in the GPU. Our performance guarantees arise from clustering both shading points and VPLs and computing visibility only among clusters' representatives. Previous approaches to the same problem resort to K-means clustering, which requires the user to specify the number of clusters; a rather unintuitive requirement. We propose an innovative massively parallel, GPU-efficient, Quality-Threshold clustering algorithm, which requires the user to specify a quality parameter. The algorithm dynamically adjusts the number of clusters depending both on the specified quality threshold and on camera-geometry conditions during execution.Attribution 4.0 International LicenseCCS Concepts: Keyword → Rendering; Ray Tracing; Global Illumination; Real-time Rendering; Parallel ProgrammingKeyword → RenderingRay TracingGlobal IlluminationRealtime RenderingParallel Programming10.2312/egp.202410432 pages