javascript - 从圆形边界弹起球

Question

这是我发现的公式:

r = v − [2 (n · v) n]

我是这样申请的

    //Calculating normal
    nx = 350 -  SmileyReds[i].xpos ;
    ny = 350 -  SmileyReds[i].ypos ;

  //new calc
   v_newx = SmileyReds[i].xspeed - (2 *( nx * SmileyReds[i].xspeed + ny * SmileyReds[i].yspeed ) ) * nx;
   v_newy = SmileyReds[i].yspeed - (2 *( nx * SmileyReds[i].xspeed + ny * SmileyReds[i].yspeed ) ) * ny;

   SmileyReds[i].xspeed = v_newx;
   SmileyReds[i].yspeed = v_newy;

但是球没有弹跳，而是在碰到边界时消失了:

完整的 src 和预览 http://jsfiddle.net/gj4Q7/4/

感谢您的宝贵时间，欢迎提供任何提示!

Answer 1

我认为你需要规范化 normal :)

之后

//Calculating normal
nx = 350 -  SmileyReds[i].xpos;
ny = 350 -  SmileyReds[i].ypos;

插入

var len = Math.sqrt(nx * nx + ny * ny);
nx = nx / len;
ny = ny / len;

您可以看到，您可以轻松获得 350*350 范围内的速度值，将您的物体弹射到太空...