坐标网格中的现实球反弹（离线）

https://cwynn.com/ball-bounce/是我几年前做的一点html5画布，它说明了op如何处理“反弹”

您有球B，它将在碰撞点C上撞到线L。B-> C线。在C以外的那条线上取一点，并在L上进行反射，以得到反射点R。当球击中C时，您可以删除它的方向向量，并将其向量设为C-> R。但是，您需要重置其速度。因此，获取方向矢量的大小，然后缩放新的方向矢量以使其匹配。

编辑：决定添加代码（这使我意识到我忘记了扩展速度）

    //closestCollPt[0] is the line the 'player' will hit next
    var dist = player.position.dist(closestCollPt[0]);

    //the 'player' in my case is a circle, so this indicates collision
    if(dist < player.radius*2)
    {
        //the collision point to the reflection like I mentioned
        //in the text above
        var newDir = closestCollPt[0].vecTo(reflection);

        //I break out their parts, b/c I want to scale the vector
        //doable in one line, but hard to debug
        var newDirX = newDir.x;
        var newDirY = newDir.y;
        var newDirDist = newDir.dist(new Vector(0,0));
        //for whatever reason I was calling the size of a vector
        //'dist' when I wrote this


        var currDirDist = player.direction.dist(new Vector(0,0));

        //give the player the direction we got from Coll->Ref
        //scale it so their speed doesn't change
        player.direction = newDir.scale(currDirDist).scale(1/newDirDist);
    }

决定添加图片...

唯一的“真实”东西是球和棕线

“球”是粉红色的，朝向光线“路径”中心的“接触”点，

投影是球在接触点上的反射，反射是投影点在线上的反射。

球接触到棕色线后，其方向向量应从“路径”更改为“新路径”（位于接触和反射线上）