#include "noises.h" displacement ripples( float Km = 1, octaves = 2;) { float offset; point PP; float filtwidth; PP = transform( "shader", P ); filtwidth = filterwidthp (PP); offset = Km * fBm( PP, filtwidth, 2.0, octaves, 0.5 ); P += offset * normalize( N ); N = calculatenormal( P ); }