k3d/share/shaders/k3d_stones.sl:13: * Uses st to create the rocks and "shader" space to create the grunge.
k3d/share/shaders/k3d_stones.sl:25: * grungefreq, grunge_Pow, grunginess = freqeuncy, power and depth of grunge
k3d/share/shaders/k3d_stones.sl:90:          grungefreq = 30, grunge_Pow = 3, grunginess = - 0.8;
k3d/share/shaders/k3d_stones.sl:107: float grunge;
k3d/share/shaders/k3d_stones.sl:159:      /* compute turbulence  for grunge*/
k3d/share/shaders/k3d_stones.sl:160:       point PP = transform("shader", P) * grungefreq;
k3d/share/shaders/k3d_stones.sl:170:        grunge = pow(turb, grunge_Pow);
k3d/share/shaders/k3d_stones.sl:171:        surface_mag += grunge * grunginess;
