langton's trans ant

int dirx = 0;
int diry = 1;
int x = 0;
int y = 0;
int omx = 0;
int omy = 0;
color[] tra = { color(91, 207, 250), color(245, 171, 185), color(255, 255, 255)};
void setup()
{
  size(displayWidth,displayHeight);
  x = round(random(round(width/5)) * 5);
  y = round(random(round(height/5)) * 5);
  frameRate(5000);
  background(0);
  noStroke();
}

void draw()
{
  if(mouseX != 0 && mouseX < 100 && mouseY < 100 && mouseX != omx)
  {
    background (0);
    x = round(random(round(width/5)) * 5);
    y = round(random(round(height/5)) * 5);
    randDir();
    omx = mouseX;
  }
  color col = get(x,y);
  if(col == tra[2])
  {
    changeDir(1);
    fill(tra[0]);
  }
  else if(col == tra[0])
  {
    changeDir(1);
    fill(tra[1]);
  }
  else if(col == tra[1])
  {
    changeDir(-1);
    fill(tra[2]);
  }
  else
  {
    changeDir(-1);
    fill(tra[0]);
  }
  rect(x,y,10,10);
  x += dirx * 10;
  y += diry * 10;
}

void changeDir(int h)
{
  if(dirx == 1){dirx = 0; diry = h; return;}
  if(dirx == -1){dirx = 0; diry = -h; return;}
  if(diry == 1){diry = 0; dirx = -h; return;}
  if(diry == -1){diry = 0; dirx = h; return;}
}

void randDir()
{
  dirx = 0;
  diry = 0;
  boolean r1 = random(1) > .5;
  boolean r2 = random(1) > .5;
  if(r1)
  {
    if(r2)
    {
      diry = 1;
    }
    else
    {
      diry = -1;
    }
  }
  else
  {
    if(r2)
    {
      dirx = 1;
    }
    else
    {
      dirx = -1;
    }
  }
}