Physically Based Rendering, 3rd Edition

16.2.5: Visible point grid construction

During the photon pass, whenever a photon intersects a surface, we need to efficiently find the visible points where the distance from the visible point to the photon’s intersection is less than the current search radius r_i for the visible point’s pixel. The implementation here uses a uniform grid over the bounding box of all of the visible points; Exercise 16.7 at the end of the chapter has you implement other data structures in place of the grid and investigate trade-offs.

〈Create grid of all SPPM visible points〉 ≡                                                             976

    〈Allocate grid for SPPM visible points 980〉

    〈Compute grid bounds for SPPM visible points 981〉

    〈Compute resolution of ...