Hierachy & Sampling

Precomputation

• Get triangles, compute BVH
• Compute BRDFs for triangles and above

CPU Side Runtime

• Load initial hierarchy
• On query (via a buffer by the GPU):
  • If in hierarchy -> load more
  • If triangle hit -> position known -> do nothing

GPU Side Runtime

• Magic BRDF on hierarchy levels only

• Something simple (phong, ...) on triangle level and below (Materialindices)

• Mip mapping gives "unbiased" input for BRDF on (sub-)triangles

• Lightsample storing

  • path vertices are stored in light cache (see GPU impl survey)
  • path vertices have a size (relevant for the random connected samples)
    • Different sized samples
  • Divide into light and view-pass samples
    • random connections only to light vertices
    • gathering/radiance estimate for both types
  • compression pass (weight all, merge only "lightweight")
    • goal: keep important samples while saving fewer samples
    • delete randomly to avoid biasing due to start conditions

Passes

• Light sample creation
  • kernel for each light type, generates samples for light light cache
• Hitpoint sample creation
• compression (?)