SOURCE

var w;

function setup(){
  createCanvas(400, 200)
  background(0)
	w = new Walker
}

function draw(){
  w.run()
}

class Walker {
  constructor(){
    // 位置向量
    this.location = new p5.Vector(0 ,0);
    // t
    this.t = new p5.Vector(0 ,10000);
  }
  
  run(){
    this.move(this.location, this.t)
    this.show(this.location)
  }
  
  show(l){
    noFill()
    stroke(255, 255, 0)
    // ellipse(this.x, this.y, 5, 5)
    point(l.x, l.y)
  }
  
  move(l, t){
		l.x += map(noise(t.x), 0,1, -1, 1 )
		l.y += map(noise(t.y), 0,1, -1, 1 )
    
    t.x += 0.01;
    t.y += 0.01;
    
    // 不要跑出去咯
    l.x = constrain(l.x, 0, width);
    l.y = constrain(l.y, 0, height);
  }

}