#include "rmannotes.sl"

surface planet(color spot_color = color(.933,.415, .313), 
        disk1_color = color(.545,.270,.074), 
	disk2_color = color(1,.725,.058),
        line_color = color(.392,.584,.929), 
        specularcolor = color (1, 1, 1); 
        float Ks = 0.6, Kd = 0.4, Ka = 0.6, roughness = 0.3, 
        radius1 = 0.35, radius2 = 0.15, radius4 = 0.05)

{
     float attenuation = 2;
     point NN = normalize(N);
     point II = normalize(I);
     float falloff = II.NN;
     color surface_color, layer1_color, layer2_color, layer3_color,
         layer4_color;
     color surface_opac, layer1_opac, layer2_opac, layer3_opac, layer4_opac;
     float fuzz = 0.025, ss, tt, j, k ;
     point center, p1,p2, Nf, V;
     float half_width, dist1, dist2, dist3, dist4, r1, r2, r4;
   
     surface_color = Cs;
     surface_opac = 0.2;
 
/* layer1 */

     ss = repeat(s,2);
     tt = repeat(t,7);
     layer1_color = spot_color;
     center = (0.5, 0.5, 0);
     r1 = radius1 + (noise(ss, tt))*0.2;
     dist1 = distance(center, (ss, tt, 0));
     layer1_opac = 1 - smoothstep(r1 - fuzz, r1, dist1);
     
     surface_color = blend(surface_color, layer1_color, layer1_opac);

/*layer2 */
     ss = repeat(s,5);
     tt = repeat(t,2);
     layer2_color = disk1_color;
     center = (0.5, 0.5, 0);
     r2 = radius2 + noise(ss*3, tt);
     half_width = 0.05;
     dist2 = distance(center, (ss, tt, 0));
     layer2_opac =  pulse(r2 - half_width, r2 + half_width, fuzz, dist2);
   
     surface_color = blend(surface_color, layer2_color, layer2_opac);

     
/*layer3 */
     ss = repeat(s,5);
     tt = repeat(t,5);
     layer3_color = line_color;
     p1 = (0.25, 0.5, 0);
     p2 = (0.35, 0.7, 0);
     half_width = 0.05;
     dist3 = ptlined(p1, p2, (ss,tt,0));
     layer3_opac = 1 - smoothstep(half_width - fuzz, half_width, dist3);

     surface_color = blend(surface_color, layer3_color, layer3_opac);

/*layer4*/
     j = repeat(ss,3);
     k = repeat(tt,1);
     ss = repeat(s,3);
     tt = repeat(t,3);
     rotate2d(ss,tt, radians(70), 0.5, 0.5, j, k);
     layer4_color = disk2_color;
     center = (0.2, 0.2, 0);
     r4 = radius4 + noise(ss, tt*5);
     half_width = 0.05;
     dist4 = distance(center, (ss, tt, 0));
     layer4_opac =  pulse(r4 - half_width, r4 + half_width, fuzz, dist4);
   
     surface_color = blend(surface_color, layer4_color, layer4_opac);
    

  if (falloff < 0) {              
                
                falloff = falloff * falloff / (II.II * NN.NN) ;
                falloff = pow(falloff, attenuation);
                Ci = surface_color * falloff;
                Oi = falloff;
        } else
                Oi = surface_opac;
}