substrate in rsl, version 1

result = 0;
point stspace = point((scale*s)+offset,(scale*(1-t))+offset,0);
uniform float i;
float x[100],y[100],dx,dy,line[100],defuzz,newlength,dist;
point p[100];
defuzz = 0;
//initialize first variables
x[0] = x1;
x[1] = x2;
y[0] = y1;
y[1] = y2;
p[0] = point(x[0],y[0],0);
p[1] = point(x[1],y[1],0);
line[0] = ptlined(p[0],p[1],stspace);
  
for (i = 1; i <= 98; i += 1) {
 newlength = cellnoise(i);
   
 dx = x[i]-x[i-1];
 dy = y[i]-y[i-1];
 dist = sqrt(pow(dx,2)+pow(dy,2));
 dx /= dist;
 dy /= dist;
   
 //perpendicular points, left and right
 x[i+1] = x[i] - (newlength/2)*dy;
 y[i+1] = y[i] + (newlength/2)*dx;
 p[i+1] = point(x[i+1],y[i+1],0);
   
 line[0] = ptlined(p[0],p[1],stspace);
 line[i] = ptlined(p[i],p[i+1],stspace);
 defuzz += 1-smoothstep(width-fuzz,width+fuzz,line[i]);
 result = defuzz;
 }