Encapsulation code for collision detection in game development using javascript_javascript skills

When developing web games with JavaScript, collision detection is required. In order to facilitate development, two collision detection methods, rectangular and circular, are encapsulated.

【Capture one with case operation】
[Note: The code has not been optimized]

Demo picture

Character attack area collision detection.gif

Tower defense case.gif

Rectangular area collision detection

/**
 * 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;
  }
 
}

Circular area collision detection

/**
 * 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;
  }
}

The above is the entire content of this article. I hope it will be helpful to everyone in understanding javascript.