在flash里用向量来制作运动模拟

向量负责用于计算力，绘图库负责把向量表示出来


下面是匀速圆周运动的例子


图片如下：







code


import Vector;


import fbook.graphics.pen.*;


import fbook.graphics.draw2d.*;


import fbook.graphics.draw2d.arrow.*;


import fbook.graphics.GDI;


var cur_mc = this;


//给球的即时速度，看受力图时可加大速度


var vel = new Vector(200, 500);


//速度向量的长度


var l=vel.getLength()


//位置向量


var pos = new Vector(move_mc._x, move_mc._y);


/***绘图****/


var _p1:IPen = new SolidPen(1, 0x000000, 100);


var _g:GDI = GDI.getInstance();


setInterval(this, "move", 30);


function move() {


  //绳子拉力


  var _lal = new Vector(move_mc._x-top_mc._x, move_mc._y-top_mc._y);


  //向量相加


  var f2 = vel.plusNew(_lal);


  _g.line(_p1, new SolidLineArrow(true, move_mc._x, move_mc._y, vel.x+move_mc._x, vel.y+move_mc._y));


  //半径


  var r = _lal.getLength();


  //相加后的长度


  var len = f2.getLength();


  //单位化


  f2.normal();


  //重新设置长度


  f2.scale(len-r);


  //改变方向后的速度


  vel.minus(f2);


  var len = vel.getLength();


  _g.target = this.createEmptyMovieClip("mc", 1);


  _g.line(_p1, new SolidLineArrow(true, top_mc._x, top_mc._y, _lal.x+top_mc._x, _lal.y+top_mc._y));


  _g.line(_p1, new SolidLineArrow(true, move_mc._x, move_mc._y, vel.x+move_mc._x, vel.y+move_mc._y));


  //_g.line(_p1, new SolidLineArrow(true, move_mc._x, move_mc._y, f3.x+move_mc._x, f3.y+move_mc._y));


  //_g.line(_p1, new SolidLineArrow(true, top_mc._x, top_mc._y, f.x+top_mc._x, f.y+top_mc._y));


  pos.plus(vel);


  


  move_mc._x = pos.x;


  move_mc._y = pos.y;


  //设置成原来的速度


  vel.normal()


  vel.setLength(l)


  


}


本文转自：http://www.5uflash.com/flashjiaocheng/Flashyingyongkaifa/883.html

在flash里用向量来制作运动模拟