//Diffusion-Limited Aggregation
Wanderer [] wanderer;
int saveCount = 0;
int w = 100;
int h = 100;
int wanderers = 300;
char [][] pix;
char [] values = {
  1,2,3};
boolean drawit = false;
int xc,yc;
void setup(){
  size (w,h);
  pix = new char[w][h];
  pix[23][23] = 1;
  pix[48][48] = 2;
  pix[73][73] = 3;
  pix[25][25] = 2;
  pix[50][50] = 3;
  pix[75][75] = 1;
  pix[28][28] = 3;
  pix[52][52] = 1;
  pix[77][77] = 2;
  wanderer = new Wanderer[wanderers];
  for(int i = 0; i < wanderers; i++){
    wanderer[i] = new Wanderer(values[i%3]);
  }
  xc = (width>>1)-50;
  yc = (height>>1)-50;
}
void draw(){
  background(50,50,50);
  for(int i = 0; i < wanderers; i++){
    wanderer[i].move();
    wanderer[i].check();
    wanderer[i].draw();
  }
  for(int i = 0; i < w; i++){
    for(int j = 0; j < h; j++){
      switch(pix[i][j]){
      case 1:
        stroke(255,0,0);
        point(xc+i,yc+j);
        break;
      case 2:
        stroke(0,255,0);
        point(xc+i,yc+j);
        break;
      case 3:
        stroke(0,0,255);
        point(xc+i,yc+j);
        break;
      }
    }
  }
}
void keyPressed(){
  pix = new char[w][h];
  pix[23][23] = 1;
  pix[48][48] = 2;
  pix[73][73] = 3;
  pix[25][25] = 2;
  pix[50][50] = 3;
  pix[75][75] = 1;
  pix[28][28] = 3;
  pix[52][52] = 1;
  pix[77][77] = 2;
  for(int i = 0; i < wanderers; i++){
    wanderer[i] = new Wanderer(values[i%3]);
  }
}
class vector{
  int x,y;
  vector(){
    reset();
  }
  void reset(){
    int option = random(1);
    switch(option){
    case 0:
      x = random(1,w-2);
      y = random(1) > 0 ? 1 : h-2;
      break;
    case 1:
      x = random(1) > 0 ? 1 : w-2;
      y = random(1,h-2);
      break;
    }
  }
}
class Wanderer{
  vector v;
  char value;
  Wanderer(char value){
    v = new vector();
    this.value = value;
  }
  void draw(){
    switch(value){
    case 1:
      stroke(255,0,0);
      break;
    case 2:
      stroke(0,255,0);
      break;
    case 3:
      stroke(0,0,255);
      break;
    }
    point(xc+v.x,yc+v.y);
  }
  void move(){
    int d = random(3);
    switch(d){
    case 0:
      v.x++;
      break;
    case 1:
      v.y++;
      break;
    case 2:
      v.x--;
      break;
    case 3:
      v.y--;
      break;
    }
    if (v.y < 1 || v.x < 1 || v.y > h-2  || v.x > w-2){
      v.reset();
    }
  }
  void check(){
    if (pix[v.x+1][v.y] == value){
      pix[v.x][v.y] = value;
      v.reset();
    }
    if (pix[v.x][v.y+1] == value){
      pix[v.x][v.y] = value;
      v.reset();
    }
    if (pix[v.x-1][v.y] == value){
      pix[v.x][v.y] = value;
      v.reset();
    }
    if (pix[v.x][v.y-1] == value){
      pix[v.x][v.y] = value;
      v.reset();
    }
  }
}