javascript制作游戏开发碰撞检测的封装代码

/** * 矩形区域碰撞检测 * Created by Administrator on 14-4-7. * author: marker */function Rectangle(x, y, _width, _height){  this.x = x;  this.y = y;   this.width = _width;  this.height = _height;     //碰撞检测(参数为此类)  this.intersects = function(obj){    var a_x_w = Math.abs((this.x+this.width/2) - (obj.x+obj.width/2));    var b_w_w = Math.abs((this.width+obj.width)/2);    var a_y_h = Math.abs((this.y+this.height/2) - (obj.y+obj.height/2));     var b_h_h = Math.abs((this.height+obj.height)/2);    if( a_x_w < b_w_w && a_y_h < b_h_h ) return true;    else return false;  } }

/** * 圆形区域碰撞检测 * Created by Administrator on 14-4-7. * author: marker * */function RadiusRectangle(x, y, radius){  this.x = x;  this.y = y;  this.radius = radius;   //碰撞检测(参数为此类)  this.intersects = function(rr){    var maxRadius = rr.radius + this.radius;    // 已知两条直角边的长度 ，可按公式：c²=a²+b² 计算斜边。    var a = Math.abs(rr.x - this.x);    var b = Math.abs(rr.y - this.y);    var distance = Math.sqrt(Math.pow(a,2) + Math.pow(b,2));// 计算圆心距离    if(distance < maxRadius){      return true;    }    return false;  }}