/*
 * PacificOcean.sl 
 *
 *  Description:
 *     Shader that generates waterwave-like pattern using turb technique.
 *
 *  Parameters: turbfreq : using for increasing or decreasing the size and 
 *                         the number of ripple.
 *                   freq: using for changing the white ripple in order to 
 *                         make an animation.    
 *             watercolor: color of water.
 *
 *  Author: Akanee  Mahasith
 */

#include "rmannotes.sl"

surface PacificOcean(float Kd = .8, Ka = .5;
                     float freq = 1;  
                     float turbfreq = 16; 
                     color watercolor = color (0.051, 0.530, 1);
                 )

{
     point PP;
     point Nf;
     float turb;
     color surface_color, layer_color;
     color surface_opac, layer_opac;
  

       /* layer 1 */

     surface_color = watercolor;
     surface_opac  = 0.5;

     Nf = faceforward(normalize(N), I);
  
     PP = transform("shader", P) * turbfreq;

     turb = 0; 
     turb += abs(snoise(PP + freq * PI));
     turb = pow((1 - turb), 8);

       /* layer 2 */

     layer_color = color (1,1,1);
     layer_opac = turb;
     surface_color = blend(surface_color, layer_color, layer_opac);
 
       /* output */

     surface_color = surface_color * (Ka * ambient() + Kd * diffuse(Nf));
     Oi = surface_opac; 
     Ci = surface_color * surface_opac;
}