javascript - 与 Chipmunk JS 的碰撞失败

Question

http://videobin.org/+70a/8wi.html

您可以看到那里正在发生的事情，并可以在此处试用演示:http://student.dei.uc.pt/~drgomes/carry/index.html .

因此，我正在使用 Chipmunk JS 演示来了解它的工作原理(请参阅 https://github.com/josephg/Chipmunk-js)。简单的演示一开始还不错，但随后事情开始疯狂地跳跃，到目前为止我一直在尝试解决这个问题，但运气不佳。

var radToDeg = 180 / Math.PI;

function PlayState() {
  this.blocks = [];

  this.setup = function() {
    space.iterations = 100;
    space.gravity = new cp.Vect(0, 150);
    space.game = this;

    this.ground = space.addShape(new cp.SegmentShape(space.staticBody, new cp.v(0, 480), new cp.v(640, 480), 0));
    this.ground.setElasticity(0);
    this.ground.setFriction(1);
  };

  this.update = function() {
    space.step(this.dt);

    for (var i = 0; i < this.blocks.length; i++) {
      var block = this.blocks[i];
      block.sprite.x = block.body.p.x;
      block.sprite.y = block.body.p.y;
      block.sprite.angle = block.body.a * radToDeg;
    }

    if (isMouseDown("left")) {
      if (this.canAddBlock) {
        this.canAddBlock = false;
        this.addBlock(mouseX, mouseY);
      }
    } else {
      this.canAddBlock = true;
    }
  };

  this.draw = function() {
    clearCanvas();

    for (var i = 0; i < this.blocks.length; i++) {
      this.blocks[i].sprite.draw();
    }

    // this.ground.sprite.draw();
  };

  this.addBlock = function(x, y) {
    width = 64;
    height = 64;

    var newBlock = new Block(x, y, width, height);

    newBlock.body = space.addBody(new cp.Body(1, cp.momentForBox(1, width, height)));
    newBlock.body.setPos(new cp.v(x, y));
    newBlock.shape = space.addShape(new cp.BoxShape(newBlock.body, width, height));
    newBlock.shape.setElasticity(0);
    newBlock.shape.setFriction(1);
    this.blocks.push(newBlock);
  };
}

desiredFPS = 60;
switchState(new PlayState());

源代码非常简单，我对我创建地面的方式表示怀疑，因为我无法真正说出它的实际位置。不过，立方体似乎找到了它并与之发生碰撞。

另一个源文件是一个小的 Block 类来帮助我组织事情:

Block = (function() {
  function constructor(x, y, width, height) {
    this.sprite = new Sprite("res/block.png", x, y);

    this.width = width;
    this.height = height;

  }

  constructor.prototype = {
    update: function() {

    }
  };

  return constructor;
})();

Answer 1

从观察行为来看，我认为这就像 Sprite 和花栗鼠的 body 不围绕同一点旋转一样简单。我相信花栗鼠的旋转是围绕质心的。看起来 Sprite 围绕左上角旋转。事实上，它们也可能是从那个 Angular 绘制的，这解释了为什么它们堆叠起来很有趣，并且与底部平面相交。

我认为您在 update 函数中需要这样的东西。 (伪代码):

offset = Vector(-width/2,-height/2) 
offset.rotate_by(block.body.a)

block.sprite.x = block.body.p.x + offset.x
block.sprite.y = block.body.p.y + offset.y