Flash游戏制作基础，跟随鼠标的曲线，曲线和其它物体之间进行碰撞检测。

首先按Ctrl+J修改属性。

创建一个MC，如下图。是放大到800%的效果。

然后直接使用鼠标跟随，下面代码直接放到第一帧，创建轨迹。

tail_len = 2;
tail_nodes = 100;
nodes = new Array();
_root.attachMovie("the_head", "the_head", 1, {_x:250, _y:200});
_root.createEmptyMovieClip("the_tail", 2);
for (x=1; x<tail_nodes; x++) {
    nodes[x] = {x:the_head._x, y:the_head._y};
}
the_head.onEnterFrame = function() {
    this._x = _root._xmouse;
    this._y = _root._ymouse;
    the_tail.clear();
    the_tail.lineStyle(2, 0x00ff00);
    the_tail.moveTo(the_head._x, the_head._y);
    nodes[0] = {x:the_head._x, y:the_head._y};
    for (var x = 1; x<tail_nodes-1; ++x) {
        rotation = Math.atan2(nodes[x].y-nodes[x-1].y, nodes[x].x-nodes[x-1].x);
        pos_x = nodes[x-1].x+tail_len*Math.cos(rotation);
        pos_y = nodes[x-1].y+tail_len*Math.sin(rotation);
        nodes[x] = {x:pos_x, y:pos_y};
        the_tail.lineTo(pos_x, pos_y);
    }
};

演示效果如下。

然后再建立一个MC设置如下，做一面墙来检测碰撞。

添加一个物体，来实验碰撞检测。添加如下Action到主场景第一帧。

tail_len = 2;
tail_nodes = 100;
nodes = new Array();
_root.attachMovie("the_head", "the_head", 1, {_x:250, _y:200});
_root.createEmptyMovieClip("the_tail", 2);
_root.attachMovie("wall", "wall", 3, {_x:250, _y:200});
for (x=1; x<tail_nodes; x++) {
    nodes[x] = {x:the_head._x, y:the_head._y};
}
the_head.onEnterFrame = function() {
    this._x = _root._xmouse;
    this._y = _root._ymouse;
    the_tail.clear();
    the_tail.lineStyle(2, 0x00ff00);
    the_tail.moveTo(the_head._x, the_head._y);
    nodes[0] = {x:the_head._x, y:the_head._y};
    for (var x = 1; x<tail_nodes-1; ++x) {
        rotation = Math.atan2(nodes[x].y-nodes[x-1].y, nodes[x].x-nodes[x-1].x);
        pos_x = nodes[x-1].x+tail_len*Math.cos(rotation);
        pos_y = nodes[x-1].y+tail_len*Math.sin(rotation);
        nodes[x] = {x:pos_x, y:pos_y};
        if (wall.hitTest(pos_x, pos_y, true)) {
            the_tail.lineStyle(2, 0xff0000);
        }
        the_tail.lineTo(pos_x, pos_y);
    }
};

效果如下。

点击这里下载源文件