# Chapter 17. Robust Multiple Specular Reflections and Refractions — Umenhoffer et al.

- Source: https://developer.nvidia.com/gpugems/gpugems3/part-iii-rendering/chapter-17-robust-multiple-specular-reflections-and-refractions
- Volume: GPU Gems 3
- Note: add-only excerpt; images omitted.

## Summary of full chapter read
Layered distance cube maps store color, distance from reference, normals. Trace secondary rays in fragment shader: uniform texture-space ray march → secant refine. Min-max sphere acceleration. Multiple bounces: read normal/Fresnel (Schlick with Fp including metals' k); n≤0 reflector, n>0 refractor, n=0 diffuse terminate. Reflective object often 2 layers (front/back) + 1 env layer. Dynamic branching; few FPS hit when increasing bounce depth. Artifacts if layers/resolution insufficient or march too coarse.