javascript实现的三维正方体(兼容ie7,ff)

2019-11-21 01:48:52

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通过更新变换矩阵来记录转动(函数remx()).
利用矩阵计算出转动后的正方体顶点坐标,
把各个顶点的空间坐标按”近大远小”转换成平面坐标(函数p2d()),
用正方体各个面的法向量的z坐标判断该面是否可见,
用高为1px的div层模拟画出四边形(函数gra2htm()).
鼠标拖曳的代码用别人的代码修改的.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> <title>Cube</title> <script type="text/javascript"> function gra2htm(clr,a,b,c,d){   var result='';   var maxx=Math.max(a[0],b[0],c[0],d[0]),minx=Math.min(a[0],b[0],c[0],d[0]);   var maxy=Math.max(a[1],b[1],c[1],d[1]),miny=Math.min(a[1],b[1],c[1],d[1]);   x=new Array(a[0],b[0],c[0],d[0],a[0],b[0],c[0],d[0],a[0],b[0]);   y=new Array(a[1],b[1],c[1],d[1],a[1],b[1],c[1],d[1],a[1],b[1]);      /*/begin   for(var i=0;i<=3;i++){     result+='<div style="position:absolute; overflow:hidden; left:'     +x[i]+'px; top:'+y[i]+'px; width:2px; height:2px; background-color:#FFF"></div>';   }   //end*/      if(maxx-minx>=maxy-miny){     for(var i=3;i<=6;i++)       if(y[i]==miny){         var k=l=i;         break;       }     if(y[k]==y[k-1]) k--;     xa=(x[k-1]-x[k])/(y[k-1]-y[k]);     if(y[l]==y[l+1]) l++;     xb=(x[l+1]-x[l])/(y[l+1]-y[l]);     pl=x[k];pw=x[l]-x[k];     for(var i=miny+1;i<=maxy;i++){       if(i>y[k-1]){         k--;         xa=(x[k-1]-x[k])/(y[k-1]-y[k]);       }       if(i>y[l+1]){         l++;         xb=(x[l+1]-x[l])/(y[l+1]-y[l]);       }       result+='<div style="overflow:hidden; top:'+i         +'px; left:'+Math.round(pl+=xa)         +'px; width:'+Math.round(pw+=xb-xa)         +'px; height:1px; position:absolute; background-color:'+clr         +';"></div>';     }   } else {     for(var i=3;i<=6;i++)       if(x[i]==minx){         var k=l=i;         break;       }     if(x[k]==x[k+1]) k++;     ya=(y[k+1]-y[k])/(x[k+1]-x[k]);     if(x[l]==x[l-1]) l--;     yb=(y[l-1]-y[l])/(x[l-1]-x[l]);     pt=y[k];ph=y[l]-y[k];     for(var i=minx+1;i<=maxx;i++){       if(i>x[k+1]){         k++;         ya=(y[k+1]-y[k])/(x[k+1]-x[k]);       }       if(i>x[l-1]){         l--;         yb=(y[l-1]-y[l])/(x[l-1]-x[l]);       }       result+='<div style="overflow:hidden; left:'+i         +'px; top:'+Math.round(pt+=ya)         +'px; height:'+Math.round(ph+=yb-ya)         +'px; width:1px; position:absolute; background-color:'+clr         +';"></div>';     }   }   return result; } function remx(type,theta,omx){   var sinA=Math.sin(theta),cosA=Math.cos(theta);   var m=new Array();   switch(type){     case 'rx':       m[0]=omx[0];m[1]=omx[1];m[2]=omx[2];       m[3]=omx[3]*cosA-omx[6]*sinA;m[4]=omx[4]*cosA-omx[7]*sinA;m[5]=omx[5]*cosA-omx[8]*sinA;       m[6]=omx[3]*sinA+omx[6]*cosA;m[7]=omx[4]*sinA+omx[7]*cosA;m[8]=omx[5]*sinA+omx[8]*cosA;       break;     case 'ry':       m[0]=omx[0]*cosA-omx[6]*sinA;m[1]=omx[1]*cosA-omx[7]*sinA;m[2]=omx[2]*cosA-omx[8]*sinA;       m[3]=omx[3];m[4]=omx[4];m[5]=omx[5];       m[6]=omx[0]*sinA+omx[6]*cosA;m[7]=omx[1]*sinA+omx[7]*cosA;m[8]=omx[2]*sinA+omx[8]*cosA;       break;   }   return m; } function p2d(x,y,z){   var l=100,t=100;   var result=new Array();   result[0]=Math.round(l+x/(z*0.004+1.25));   result[1]=Math.round(t+y/(z*0.004+1.25));   return result; } </script> <script type="text/javascript"> //const   var pa=new Array();   pa[1]=new Array(50,50,-50);   pa[2]=new Array(50,50,50);   pa[3]=new Array(50,-50,50);   pa[4]=new Array(50,-50,-50);   pa[5]=new Array(-50,50,-50);   pa[6]=new Array(-50,50,50);   pa[7]=new Array(-50,-50,50);   pa[8]=new Array(-50,-50,-50);   var idx=new Array();   idx[0]=new Array(1,2,3,4);   idx[1]=new Array(1,4,8,5);   idx[2]=new Array(1,5,6,2);   idx[3]=new Array(7,3,2,6);   idx[4]=new Array(7,8,4,3);   idx[5]=new Array(7,6,5,8);   var clr=new Array('#03c','#c00','#fc0','#f60','#fff','#090'); //end function cube(id){   if(!document.getElementById(id)) return false;   this.id=document.getElementById(id);   this.angle=new Array();   this.angle2=new Array();   for(i=1;i<=8;i++) this.angle[i]=new Array(3); //  alert('success'); } cube.prototype={   matrix:new Array(1,0,0,0,1,0,0,0,1),   paint:function(){     var result='';     for(i=1;i<=8;i++){       this.angle[i][0]=this.matrix[0]*pa[i][0]+this.matrix[1]*pa[i][1]+this.matrix[2]*pa[i][2];       this.angle[i][1]=this.matrix[3]*pa[i][0]+this.matrix[4]*pa[i][1]+this.matrix[5]*pa[i][2];       this.angle[i][2]=this.matrix[6]*pa[i][0]+this.matrix[7]*pa[i][1]+this.matrix[8]*pa[i][2];       this.angle2[i]=p2d(this.angle[i][0],this.angle[i][1],this.angle[i][2]);     }     for(i=0;i<6;i++){       if((this.angle2[idx[i][2]][0]-this.angle2[idx[i][1]][0])*         (this.angle2[idx[i][0]][1]-this.angle2[idx[i][1]][1])-         (this.angle2[idx[i][2]][1]-this.angle2[idx[i][1]][1])*         (this.angle2[idx[i][0]][0]-this.angle2[idx[i][1]][0])<0){           result+=gra2htm(clr[i],this.angle2[idx[i][3]],this.angle2[idx[i][2]],this.angle2[idx[i][1]],           this.angle2[idx[i][0]]);       }     } //    document.getElementById('aa').value=result;     this.id.innerHTML=result;   },   roll:function(type,theta){     this.matrix=remx(type,theta,this.matrix); //    this.paint();   } } </script> <script type="text/javascript"> var tmr=(new Date()).getTime(); function drag(obj,e){   e=e?e:window.event;   var setx=e.clientX,sety=e.clientY;            if(document.addEventListener){              document.addEventListener('mousemove', inFmove, true);              document.addEventListener('mouseup', inFup, true);          } else if(document.attachEvent){              document.attachEvent('onmousemove', inFmove);              document.attachEvent('onmouseup', inFup);          }              function inFmove(e){     tmr2=(new Date).getTime();     if(tmr2-tmr<100) return false;     tmr=tmr2;     cc.roll('ry',(e.clientX-setx)/50);     setx=e.clientX;     cc.roll('rx',(e.clientY-sety)/50);     sety=e.clientY;     cc.paint();     return false;   }   function inFup(){              if(document.removeEventListener){                  document.removeEventListener('mousemove', inFmove, true);                  document.removeEventListener('mouseup', inFup, true);              } else if(document.detachEvent){                  document.detachEvent('onmousemove', inFmove);                  document.detachEvent('onmouseup', inFup);              }    } // shawl.qiu script  } </script> </head> <body> <div id="t" style="width:200px;height:200px;background-color:#000000;" oncontextmenu="return false" onmousedown="drag(this,event)"></div>  <input type="button" onClick="clearInterval(tt)" value="Stop" /> <input type="button" onClick="clearInterval(tt);tt=setInterval('cc.roll(/'rx/',0.2);cc.paint();',100)" value="Down" /> <input type="button" onClick="clearInterval(tt);tt=setInterval('cc.roll(/'ry/',0.2);cc.paint();',100)" value="Right" /> <script type="text/javascript"> var tt,cc=new cube('t'); cc.roll('ry',1); cc.paint(); </script> </body> </html>

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