简单圆形碰撞检测

整理以前的文件时看到之前写过的圆形的碰撞检测，简单记录下。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <canvas id="cav" width="500" height="500"></canvas>

    <script>
        var cav = document.getElementById('cav'),
            ctx = cav.getContext('2d');

        var b1 = {
            r:40,
            x:100,
            y:100
        };

        var b2 = {
            r:40,
            x:165,
            y:100
        };
        

        function draw(){
            for(var i=0; i<arguments.length; i++){
                ctx.fillStyle = '#333';
                ctx.beginPath();
                ctx.arc(arguments[i].x,arguments[i].y,arguments[i].r,0,Math.PI*2);
                ctx.fill();
            }
        }
        draw(b1,b2);

        function getBound(circle){
            return{
                x:circle.x - circle.r,
                y:circle.y - circle.r,
                w:circle.r*2,
                h:circle.r*2
            }
        }

        function collision(c1,c2){
            //如果碰撞了就返回true
            return !(c1.x + c1.w < c2.x ||
                    c1.y + c1.h < c2.y ||
                    c2.x + c2.w < c1.x ||
                    c2.y + c2.h < c1.y
                );
        }

        var r = collision(getBound(b1),getBound(b2));
        console.log(r);

    </script>
</body>
</html>

 

posted @ 2017-05-20 23:26  _Jo  阅读(1050)  评论(0)  编辑  收藏  举报