Question

如果球触及挡块的顶部和底部，我怎么能改变它的dy？现在它只是一个摆动效果，当它击中顶部或底部时被困在块内。这是我的Jsfiddle：https://jsfiddle.net/6qh70wdo/

<!DOCTYPE html>

<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=Edge" >
    <!--... more here...-->
  </head>
  <body>
    <!--... more here...-->
    <input type="text" id="wall_color_picker" onclick="startColorPicker(this)" title="Wall Color" value="#FFFFFF">
    <!--... more here...-->
  </body>
</html>

Answer 1

我会把它分成两部分。首先检测它是否被击中然后担心它击中的位置。我想你可以这样做：

var bool = ball.x - ball.radius < block.x + block.w &&
    ball.x + ball.radius > block.x &&
    ball.y - ball.radius < block.y + block.h &&
    ball.y + ball.radius > block.y) {
    ball.dx  = -ball.dx;

if(bool) // if true, meaning a hit, find which direction.
    if(ball.x - ball.radius < block.x + block.w || ball.x + ball.radius > block.x){
        ball.dx = -ball.dx; //hit detected on left/right...change left/right direction
    }else{
        ball.dy = -ball.dy; //hit detected on top/bottom...change top/bottom direction
    }
}

矩形和圆形解决了碰撞

1 个答案: