eyes.osl

float dist2cell(point p, string spacename, float freq, float jitter) {
    point pp = transform(spacename, p) * freq;
    point thiscell = point(floor(pp[0]) + 0.5,
                           floor(pp[1]) + 0.5,
                           floor(pp[2]) + 0.5);
    float dist2nearest = 1000;
    int i,j,k;
    for(i = -1; i <= 1; i += 1)
       for(j = -1; j <= 1; j += 1)
           for(k = -1; k <= 1; k += 1) {
              point testcell = thiscell + vector(i,j,k);
              point pos = testcell + (noise("snoise", testcell) * jitter) - 0.5;
              float dist = distance(pos, pp);
              if(dist < dist2nearest)
                 dist2nearest = dist;
              }
    return dist2nearest;
    }
//-------------------------------------------------------
shader
eyes(float cellfreq = 5,
         float radius = 0.15,
         float blur = 0.1,
         float jitter = 1,
         color patcolor = color(1,0,1),
         color bakcolor = color(1,1,1),
         string spacename = "shader",
    output color resultRGB = 0,
    output float resultMask = 0,
    output float resultF = 0)
{
float d = dist2cell(P, spacename, cellfreq, jitter);
resultF = 1 - smoothstep(radius, radius + blur, d);
resultRGB = mix(bakcolor, patcolor, resultF); 
resultMask = (d <= radius) ? 1 : 0;
}