Hardware-Accelerated Web Ray Tracing Architecture in WebGPU
Building real-time path tracers in browsers using Bottom-Level (BLAS) and Top-Level Acceleration Structures (TLAS) in WGSL.
Traditional WebGL rasterization approximates realistic lighting via shadow maps and reflection probes. WebGPU enables true hardware-driven ray tracing pipelines capable of evaluating real-time global illumination and path-traced reflections directly on client GPUs.
1. Bounding Volume Hierarchies: BLAS and TLAS
Ray tracing efficiency relies on spatial acceleration structures. Bottom-Level Acceleration Structures (BLAS) store static mesh triangles, while Top-Level Acceleration Structures (TLAS) hold scene instance transforms for fast ray intersection queries.
2. Ray Generation and Closest-Hit Compute Shaders
Dispatching ray generation compute passes calculates primary view rays from camera origins. Intersection shaders evaluate ray-triangle collisions, passing material attributes to closest-hit passes for recursive indirect bounce calculations.
3. Progressive Accumulation and Temporal Denoising
To maintain 60 FPS viewport interaction during camera movement, path tracers accumulate noisy lighting samples across static frames while applying spatio-temporal denoisers to filter monte carlo variance.