Name
refract - computes a refraction vector.
Synopsis
fixed3 refract(fixed3 i, fixed3 n, fixed eta); half3 refract(half3 i, half3 n, half eta); float3 refract(float3 i, float3 n, float eta);Parameters
- i
- Incidence vector.
- n
- Normal vector.
- eta
- Ratio of indices of refraction at the surface interface.
Description
Returns a refraction vector given an incidence vector, a normal vector for a surface, and a ratio of indices of refraction at the surface's interface.
The incidence vector i and normal vector n should be normalized.
Reference Implementation
reflect for float3 vectors could be implemented this way:
float3 refract( float3 i, float3 n, float eta ) { float cosi = dot(-i, n); float cost2 = 1.0f - eta * eta * (1.0f - cosi*cosi); float3 t = eta*i + ((eta*cosi - sqrt(abs(cost2))) * n); return t * (float3)(cost2 > 0); }Profile Support
refract is supported in all profiles.
Support in the fp20 is limited.
See Also