js实现的牛顿摆效果

(function(window,undefined){  window.None || (window.None = {});  //重力加速度  var G=9.8;  var PI=Math.PI;  //帧频  var FPS=48; /*//IE角度转换function rorateIt(node,deg){  //取得末变形前矩形的中点  var rect = node.getBoundingClientRect(),  cx1 = (rect.right - rect.left) / 2, // center x  cy1 = (rect.bottom - rect.top) / 2, // center y  deg2rad = Math.PI / 180,//角度转弧度  rad = deg * deg2rad ,  cos = Math.cos(rad),  sin = Math.sin(rad);  var ident = "DXImageTransform.Microsoft.Matrix";  node.style.filter = "progid:"+ident +"(M11='1.0',sizingmethod='auto expand')";  //http://www.satzansatz.de/cssd/onhavinglayout.html  if(!node.currentStyle.hasLayout){//在IE7中，如果没有获得hasLayout，滤镜会失效   node.style.writingMode = "tb-rl";  }    var filter = node.filters.item(ident);  // +-------+-------+  // | M11 | M12 |  // +-------+-------+  // | M21 | M22 |  // +-------+-------+  filter.M11 = cos;       filter.M12 = -sin;       filter.M21 = sin;        filter.M22 = cos;       //取得当前中心  rect = node.getBoundingClientRect();  var cx = (rect.right - rect.left) / 2;  var cy = (rect.bottom - rect.top) / 2;  //调整此元素的坐标系，实现CSS3 transform-origin的功能  node.style.marginLeft = cx1 - cx + "px";  node.style.marginTop = cy1 - cy + "px";}    */  //外部函数引用  //是否IE  function isIE(){    return navigator.userAgent.indexOf("MSIE")>-1;  }  //获取当前样式  function returnStyle(obj,styleName){     var myObj = typeof obj == "string" ? document.getElementById(obj) : obj;     if(document.all){       return eval("myObj.currentStyle." + styleName);     } else {       return eval("document.defaultView.getComputedStyle(myObj,null)." + styleName);     }   }   //外部函数引用  //图片方法  var img=function(src){    var img=new Image();    img.src=src;    return img;  }  //方向类，以垂直向下为0度逆时针为正  var face=function(deg,rad){    //0-360    this.unit='deg';    if(rad)deg=180/PI*deg;    this.deg=deg;    this.rad=PI/180*this.deg;  }  //矢量类  var vector=function(size,fx){    var cstrct=this.constructor;    this.size=size;    this.face=fx||new face(0);    fx=this.face;    this.toHv=function(){      var h=new cstrct(Math.sin(fx.rad)*size,90);      var v=new cstrct(Math.cos(fx.rad)*size,0);      return [h,v];        }  }  //继承，obj:需要从矢量继承的对象,arg:arguments  vector.extend=function(obj,arg){    vector.apply(obj,arg);  }  //矢量合并方法  vector.merger=function(arrvector){    if(arguments.length>1)arrvector=arguments;    var cstrct=arrvector[0].constructor;    var i=0,ilav=arrvector.length;    var sum=[0,0];    for(;i<ilav;i++){      var hv=arrvector[i].toHv();      sum[0]+=hv[0].size;      sum[1]+=hv[1].size;    }    var size=Math.sqrt(sum[0]*sum[0]+sum[1]*sum[1]);    var fa=new face(Math.atan(sum[0]/sum[1]),'rad');    return new cstrct(size,fa);  }  //力类,参数为大小和方向  var force=function(size,face){    this.unit='N';    //继承自矢量    vector.apply(this,arguments);  }  //加速度类  var a=function(size,face){    this.unit='m/s^2';    vector.extend(this,arguments);  }  //速度类  var speed=function(size,face){    this.unit='m/s';    vector.extend(this,arguments);  }   //刚体类,参数(body:IMG对象,m为质量)  var rigid=function(body,m){    //一般情况下body为一个img对象，所以暂且只有正方形或长方形两种形式    this.body=body;     this.m=m;      //质量    this.focus=(this.body instanceof Image)?point(this.body.width/2,this.body.height/2):point(this.body.style.width/2,this.body.style.height/2);    this.axis=point(0,0);  //轴心位置(point对象)         this.force=new force(0);    this.a=new a(this.force.size/this.m,this.force.face);    this.speed=new speed(0);    //设置，可重新设置上面所有参数    this.set=function(prop,value){      this[prop]=value;    }    this.addForce=function(f){      return this.force=vector.merger(f,this.force);    }           //旋转    this.rotate=function(face,axis){      axis=axis||this.axis||this.focus;      //cx1=returnStyle(this.body,"left");      //cy1=returnStyle(this.body,"left");      var rect=this.body.getBoundingClientRect(),      //cx1=rect.left+axis.x,      //cy1=rect.top+axis.y,      cx1 = (rect.right - rect.left) / 2,      cy1 = (rect.bottom - rect.top) / 2,      rad=face.rad,      cos = Math.cos(rad),      sin = Math.sin(rad);      if(isIE()){        var ident = "DXImageTransform.Microsoft.Matrix";        this.body.style.filter = "progid:"+ident +"(M11='1.0',sizingmethod='auto expand')";        if(!returnStyle(this.body,"hasLayout")){//在IE7中，如果没有获得hasLayout，滤镜会失效          this.body.style.writingMode = "tb-rl";        }          var filter = this.body.filters.item(ident);        filter.M11 = cos;             filter.M12 = -sin;             filter.M21 = sin;              filter.M22 = cos;        }      rect = this.body.getBoundingClientRect();      //var cx=rect.left+axis.x;      //var cy=rect.top+axis.y;      var cx = (rect.right - rect.left) / 2;      var cy = (rect.bottom - rect.top) / 2;      //调整此元素的坐标系，实现CSS3 transform-origin的功能      this.body.style.left=parseInt(this.body.style.left,10) + cx1 - cx + "px";      this.body.style.top=parseInt(this.body.style.top,10) + cy1 - cy + "px";      //CSS3      var sdeg="rotate("+face.deg+"deg)";      var paxis=axis.x+"px "+axis.y+"px";      this.body.style.transformOrigin=paxis;      this.body.style.MozTransformOrigin=paxis;      this.body.style.WebkitTransformOrigin=paxis;      this.body.style.OTransformOrigin=paxis;      this.body.style.WebkitTransform=sdeg;      this.body.style.MozTransform=sdeg;      this.body.style.OTransform=sdeg;      this.body.style.transform=sdeg;    }  }  //刚体组合  rigid.merger=function(){       }  //无弹性绳子类  var rope=function(body,length,maxForce){    this.body=body;    this.length=length;    this.maxForce=maxForce || Infinity || Number.MAX_VALUE;  }  //组合体类  var comb=function(arrObject){       }  //单摆类  var pendulum=function(ripe,rigid){       }     //类单摆  var likePend=function(rigid,fa,time){//刚体,初始角度,摆动频率    var self=this;    this.rigid=rigid;    this.body=this.rigid.body;    this.axis=this.rigid.axis;    this.dom=this.rigid.dom;    this.m=this.rigid.m;    this.rad=fa?fa.rad:fa=new face(PI/6,'rad');    //摆动    //角度30    var fx=fa.rad;    //角度平方根    var m=Math.sqrt(fx);    //摆动时间1秒    var atime=time||0.5;    var fnum=FPS*atime;    //单位增量    var fm=m/fnum;    //i:角度平方根到0    var i=-m,tid;    var g=new a(G);    var t=1000/FPS;    //o:{s:1,f:30,t:0,fun:callback}  :s:(-1,1)速度增加还是减小,f:从多少度,t:到多少度,fun:摆完后运行的函数    this.swing=function(o,fun){/*     var asps=g.size*Math.cos(PI/2-fx)/(24*24*self.m);       var fss=new force(asps,new face(fx-PI/2));      this.rigid.force=fss;      var a=this.rigid.a;      //单位时间内速度的增量      var a1=Math.acos((asps+this.rigid.speed.size)/2)      this.rigid.speed=new speed(a1,new face(fx-PI/2));      a2=a1*2;*/      //{s:-1,inc:1}      o=o||{s:1};      var y=-o.s*i*i+fx*o.s;      if(i>=m){        self.rigid.rotate(new face(0),self.axis);        clearTimeout(tid);        i=-m;        if(fun)fun();        return;      }      var f=new face(y,'rad');      self.rigid.rotate(f,axis=self.axis);      i+=fm;      tid=setTimeout(function(){self.swing.call(self,o,fun)},t);    }         this.moveTo=function(p){      self.body.style.left=p.x+"px";      self.body.style.top=p.y+"px";    }  }     //世界  None.world=function(param){    //param:{force:[多个force对象]}    this.param=param||{};    this.config={      //全局外力      g:new a(G),      className:'',      width:'100%',      height:'100%',      left:0,      top:-200,      arrNav:['about','myWork','site','other','myTools'],      imgW:60,      imgN:5,      sDeg:5,      hitSound:'sounds/hit.wav',      vol:0.1    }    this.init();  };  None.world.prototype={    //初始化    dom:{},    init:function(){      var c=this.config;      var p=this.param;      //dom          var dom=document.createElement("div");      dom.className=c.className;      dom.style.position="absolute";      dom.style.width=p.width||c.width;      dom.style.height=p.height||c.height;      dom.style.left=(p.left||c.left) +"px";      dom.style.top=(p.top||c.top) +"px";      this.dom=dom;      document.body.appendChild(this.dom);    },    //添加一个刚体    addRigid:function(rigid,p){      if(!(rigid instanceof Array)){        rigid=[rigid];      }      if(!p)p=[point(0,0)];      if(!(p instanceof Array))p=[p];      for(var i=0,rl=rigid.length;i<rl;i++){        p[i]=p[i] || p[0];        rigid[i].body.style.position="absolute";        rigid[i].body.style.left=p[i].x+"px";        rigid[i].body.style.top=p[i].y+"px";        this.dom.appendChild(rigid[i].body);      }    },    //添加一个外作用力    addForce:function(){           },    start:function(){      var p=this.param,      c=this.config;      var shit=p.hitSound||c.hitSound;      var sndHit=new None.sounds(shit);      sndHit.volume=p.vol||c.vol;      var w=document.documentElement.offsetWidth;      var imgWidth=p.imgW||c.imgW;//图片宽度      var imgNum=p.imgN||c.imgN; //图片数量      var jd=p.sDeg||c.sDeg;   //最大角度      var es=p.arrNav||c.arrNav;      var time=p.time||c.time;             var basex=w/2-imgWidth*imgNum/2;      var jiaodu=new face(jd);      var rig=[],ball=[],pend=[],axis=point(imgWidth/2,0);      for(var i=0,el=es.length;i<el;i++){        rig[i]=document.getElementById(es[i]);        ball[i]=new rigid(rig[i],1);        ball[i].set("axis",axis);        pend[i]=new likePend(ball[i],jiaodu,time);      }      this.addRigid(pend);      resize();      if(!isIE())swing();      window.onresize=resize;             function hit(v){        sndHit.play();       }      function swing(){        var runfun=arguments.callee;        var last=pend.length-1;        if(p.hitSound)hit(0);        pend[0].swing({s:1},function(){          if(p.hitSound)hit(1);          pend[last].swing({s:-1},runfun);        });      }      function resize(){        var w=document.documentElement.offsetWidth;        var basex=w/2-imgWidth*imgNum/2;        var n=pend.length;        for(var i=0;i<n;i++){          pend[i].moveTo(point(basex+imgWidth*i,0));         }      }      }  };   })(window);