Chapter 18. Relaxed Cone Stepping for Relief Mapping — Policarpo, Oliveira

• Source: https://developer.nvidia.com/gpugems/gpugems3/part-iii-rendering/chapter-18-relaxed-cone-stepping-relief-mapping
• Volume: GPU Gems 3
• Note: add-only excerpt for wiki ingest; images omitted; prose and key listings kept.

Summary of full chapter read

Relief mapping ray-heightfield: linear search + binary search aliases thin features; CSM (Dummer) never misses but stops early (distortion). Relaxed cone stepping: cones allowed to pierce surface at most once → much wider cones → aggressive space-leap then binary refine.

Cone map

Store cone ratio w/h per texel (with depth). Offline O(n²): for each source, find max angle such that a ray inside the cone never exits the heightfield after entering. Clamp ratio ≤1 for 8-bit.

Runtime

Transform view to tangent space; cone-step fixed iterations until under surface; binary search from H–K. Self-shadow with same cones. Depth scale/tiling via ray direction only. Prefer separate depth/normal textures; careful mip of cone maps (min, not average).