Rotating Diffusion-Limited Aggregation

#!/usr/bin/env gmic
# File : rotating_dla.gmic
# Author : David Tschumperle

# Entrypoint when run from CLI:
go =>[^] "Rotating Diffusion Limited Aggregation" e[] "" animate 60

# Main function
go :
  v 0
  480,480 noise 0.001,2 != 0
  nbf=300
  repeat $nbf { f=$>
    e[] "
  > Frame "{$f+1}/$nbf
    +>[0] 0.45 distance. 1 b. 1 g. xy,6 a[-2--1] c orientation.
    1000,1,1,1,":
      do (x = v(w#0 - 1); y = v(h#0 - 1), i(#0,x,y));
      repeat (w#0,k,
        G = I(#-1,x,y,0,1);
        dl = 1/max(abs(G));
        nx = x - dl*G[0];
        ny = y - dl*G[1];
        i(#0,round(nx),round(ny))?break();
        x = nx; y = ny;
      );
      i(#0,x,y) = 1"
    rm[-2,-1]

    # Render frame.
    +b[0] 2,3 *. 800 c. 0,255 map. curl
    rotate[0] 2,1,0,50%,50% zoom[0] 0.97
  }
  rm[0]

# End of file.