二维空间中的 Javascript 物理

Question

因此，我正在努力自学 Canvas (HTML5) 并编写了大部分简单的游戏引擎代码。它是空间场景(行星、恒星、天体等)的二维表示。我的默认“Sprite”类有一个像这样的帧监听器:

“baseClass”包含一个允许继承并将“a”应用于“this.a”的函数。所以，“var aTest = new Sprite({foo: 'bar'});”会使“aTest.foo = 'bar'”。这就是我将对象相互公开的方式。

Sprite = baseClass.extend({
  init: function(a){
    baseClass.init(this, a);
    this.fields = new Array(); // list of fields of gravity one is in. Not sure if this is a good idea.
    this.addFL(function(tick){ // this will change to be independent of framerate soon.

      // gobjs is an array of all the Sprite objects in the "world".
      for(i = 0; i < gobjs.length; i++){

        // Make sure its got setup correctly, make sure it -wants- gravity, and make sure it's not -this- sprite.
        if(typeof(gobjs[i].a) != undefined && !gobjs[i].a.ignoreGravity && gobjs[i].id != this.id){
          // Check if it's within a certain range (obviously, gravity doesn't work this way... But I plan on having a large "space" area,
          // And I can't very well have all objects accounted for at all times, can I?
          if(this.distanceTo(gobjs[i]) < this.a.size*10 && gobjs[i].fields.indexOf(this.id) == -1){
            gobjs[i].fields.push(this.id);
          }
        }
      }
      for(i = 0; i < this.fields.length; i++){
        distance = this.distanceTo(gobjs[this.fields[i]]); 

        angletosun = this.angleTo(gobjs[this.fields[i]])*(180/Math.PI); // .angleTo works very well, returning the angle in radians, which I convert to degrees here.

        // I have no idea what should happen here, although through trial and error (and attempting to read Maths papers on gravity (eeeeek!)), this sort of mimics gravity.
        // angle is its orientation, currently I assign a constant velocity to one of my objects, and leave the other static (it ignores gravity, but still emits it).
        // This cant be right, because it just _sets_ the angle regardless of whatever it was.
        // This is where we need to find "the average of the forces".
        this.a.angle = angletosun+(75+(distance*-1)/5); //todo: omg learn math

        if(this.distanceTo(gobjs[this.fields[i]]) > gobjs[this.fields[i]].a.size*10){
          this.fields.splice(i); // out of range, stop effecting.
        }
      }
    });

    //draw objects based on new position (from fixed velocity and angle).

  }
});

提前致谢。真正的诀窍是那一行，顺便说一句，我知道这毫无意义。度数 + 距离 = 失败。

this.a.angle = angletosun+(75+(distance*-1)/5);

这比 Javascript 更像是一个物理问题，但我搜索并阅读了很多关于轨道数学的维基文章方式。 很快我就忘记了。

Answer 1

哦，这让我想起了往事，玩物理模拟非常有趣。

无论如何，听起来你需要完善你的矢量数学，这可能是最重要的事情，这篇文章应该包含你需要知道的关于矢量数学的一切，虽然我不确定它是否是最简单的可用资源。 http://en.wikipedia.org/wiki/Euclidean_vector

您的代码似乎有点过度面向对象，当然这是一个偏好问题，但我会坚持使用纯数据对象并将逻辑保留在单独的函数中。

这里有一些物理数学可以帮助您入门，每个对象都应该有一个矢量位置、一个矢量速度和质量。

对于每个刻度你做两件事，对于每个对象你将速度添加到位置:

p=p+v

对于每个物体相对于其他每个物体，您根据计算出的引力改变速度。由于 A 的引力井，B 的速度会像这样变化:

B.v=B.v+(A.p-B.p)*(A.m/(|A.p-B.p|^3))

一旦你破解了矢量数学，你应该能够将其转化为实际代码。