如何实现这一"follow another sprite"运动？

Question

在划痕中，我正在尝试实现这一"遵循另一个精灵"的运动，在该运动中，另一个精灵遵循了第一个精灵的运动，就像在这场比赛中一样，信仰山：

https://www.youtube.com/watch?v=fqhyhod2-ck

基本上，我正在寻找的是伪代码，这对我的划痕和JavaScript都可以帮助我。我不确定该怎么做(显然(涉及其他精灵的X和Y位置。

谢谢。

Answer 1

这是一些伪代码，可以使您开始。这绝对不是您的最终解决方案；您将必须处理细节，才能完全像您想要的那样获取它。祝您好运！

let trackingArrayMaxSize = 100;
let trackingArrayFollowerStart = 50;
var trackingArrayLeaderIndex = 0;
var trackingArrayFollowerIndex = 0;
var trackingArray = [ ];
// Scratch, or whatever game engine you're using, is going to call this once per frame.
// Have a look at the Scratch wiki https://en.scratch-wiki.info/wiki/Game_Loop
// to see how Scratch does it.
function update() {
  ////////////
  // Use the array to track the current position of the main sprite.
  ////////////
  if(trackingArray.number_of_elements < trackingArrayMaxSize) {
    // If the tracking array hasn't reached the max size, then
    // just keep appending our current position to it.
    trackingArray.append(main_sprite_current_position)
  } else {
    // If we've reached the max size, then we start treating the
    // array as a circular array, storing each new position in the
    // next array index as normal, but wrapping back to index 0
    // when we reach the end.
    trackingArray[trackingArrayLeaderIndex] = main_sprite_current_position
    trackingArrayLeaderIndex = (trackingArrayLeaderIndex + 1) % trackingArrayMaxSize
  }
  ////////////
  // Read back from the array to set the position of your following sprite
  ////////////
  if(trackingArray.number_of_elements > trackingArrayFollowersStart) {
    // When the array becomes full enough (experiment to decide how full),
    // set your follower position to wherever the leader was, that many frames before.
    //
    //
    // So say we start with trackingArrayMaxSize = 100 and trackingArrayFollowersStart = 50.
    // At the top of this function each frame, we'll be storing the leader's positions into
    // the array. When the array has 50 elements in it, we come here and set the
    // follower's position to trackingArray[0] -- and up top, we'll be storing the leader's
    // position to trackingArray[50].
    //
    // Next time through, we'll store leader to trackingArray[51], and here we'll be setting the
    // follower's position to trackingArray[1]. So your follower will always be 50 frames
    // behind your leader.
    following_sprite_current_position = trackingArray[trackingArrayFollowerIndex]
    trackingArrayFollowerIndex = (trackingArrayFollowerIndex + 1) % trackingArrayMaxSize
  }
}

Answer 2

这种类型的问题是反向运动学之一。我创建了一个前一段时间这样做的项目。https://scratch.mit.edu/projects/250005153/

本质上，您要做的是让小组的每个连续成员都向成员移动，如果它大于一定距离。例如，这种距离就像圆的半径。这模仿了链中绳索或原子的现实生活。希望这会有所帮助！

Answer 3

我对javascript还不了解这种事情在刮擦中真的很容易。

指向精灵，移动(精灵的速度(步骤。完成。

如果那样行不通，转到Sprite，指向Sprite的方向，转180，移动所需距离，并为每个链接进行此操作，并且指向每个并发以下以下链接的链接其他。(换句话说，要指向该行中的最后一个方向(

这可以用多个精灵(最简单的方式(完成，变量设置临时位置和冲压，清单和冲压，或您可以使用克隆(这更复杂(。