最近研究魔方的玩法，就突然想用HMTL5寫一個魔方的模型，由于魔方是一個3D的立方體，這次就試著用HTML5寫了一個簡單的3D模型。
下面是預覽畫面。
制作流程
首先你需要下載Html5開源庫件lufylegend-1.4.0
魔方分為6個面，每個面由9個小矩形組成，現在我把每個小矩形當做一個類封裝起來，
因為現在建立的是一個3D魔方，所以要畫出每個小矩形，需要知道小矩形的4個定點，而這4個定點會根據空間的旋轉角度而變換，所以為了計算出這4個定點坐標，需要知道魔方繞x軸和z軸旋轉的角度。
所以，建立矩形類如下
function Rect(pointA,pointB,pointC,pointD,angleX,angleZ,color){ base(this,LSprite,[]); this.pointZ=[(pointA[0]+pointB[0]+pointC[0]+pointD[0])/4,(pointA[1]+pointB[1]+pointC[1]+pointD[1])/4,(pointA[2]+pointB[2]+pointC[2]+pointD[2])/4]; this.z = this.pointZ[2]; this.pointA=pointA,this.pointB=pointB,this.pointC=pointC,this.pointD=pointD,this.angleX=angleX,this.angleZ=angleZ,this.color=color; } Rect.prototype.setAngle = function(a,b){ this.angleX = a; this.angleZ = b; this.z=this.getPoint(this.pointZ)[2]; }; pointA,pointB,pointC,pointD是小矩形的四個頂點，angleX,angleZ分別是x軸和z軸旋轉的角度，color是小矩形的顏色。
魔方分為6個面，先看一下最前面的一面，如果以立方體的中心作為3D坐標系的中心，那么9個小矩形的各個定點所對應的坐標如下圖所示
所以，前面這個面的9個小矩形可以由下面的代碼來建立
for(var x=0;x<3;x++){ for(var y=0;y<3;y++){ z = 3; var rect = new Rect([-3*step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-step + y*2*step,-3*step + z*2*step],[-3*step + x*2*step,-step + y*2*step,-3*step + z*2*step],0,0,"#FF0000"); backLayer.addChild(rect); } } 其中backLayer是一個LSprite類，step是半個小矩形的長，同樣的道理，可以也得到其他5個面。
6個面都建立了，在繪制這6個面之前，首先要根據旋轉的角度來計算各個定點的坐標，看下面的圖
根據上面的圖，用下面的公式即可得到變換后的定點坐標
Rect.prototype.getPoint = function(p){ var u2,v2,w2,u=p[0],v=p[1],w=p[2]; u2 = u * Math.cos(this.angleX) - v * Math.sin(this.angleX); v2 = u * Math.sin(this.angleX) + v * Math.cos(this.angleX); w2 = w; u = u2; v = v2; w = w2; u2 = u; v2 = v * Math.cos(this.angleZ) - w * Math.sin(this.angleZ); w2 = v * Math.sin(this.angleZ) + w * Math.cos(this.angleZ); u = u2; v = v2; w = w2; return [u2,v2,w2]; }; 最后根據小矩形的四個定點坐標，來繪制這個矩形，
Rect.prototype.draw = function(layer){ this.graphics.clear(); this.graphics.drawVertices(1,"#000000",[this.getPoint(this.pointA),this.getPoint(this.pointB),this.getPoint(this.pointC),this.getPoint(this.pointD)],true,this.color); }; 其中drawVertices是lufylegend.js庫件中LGraphics類的一個方法，它可以根據傳入的定點坐標數組來繪制一個多邊形。
最后，給出完整代碼，代碼很少，JS代碼一共91行。
一，index.html
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>3D魔方</title> </head> <body> <div id="mylegend">loading……</div> <script type="text/javascript" src="../lufylegend-1.4.0.min.js"></script> <script type="text/javascript" src="./Main.js"></script> <script type="text/javascript" src="./Rect.js"></script> </body> </html>
二，Rect類
function Rect(pointA,pointB,pointC,pointD,angleX,angleZ,color){ base(this,LSprite,[]); this.pointZ=[(pointA[0]+pointB[0]+pointC[0]+pointD[0])/4,(pointA[1]+pointB[1]+pointC[1]+pointD[1])/4,(pointA[2]+pointB[2]+pointC[2]+pointD[2])/4]; this.z = this.pointZ[2]; this.pointA=pointA,this.pointB=pointB,this.pointC=pointC,this.pointD=pointD,this.angleX=angleX,this.angleZ=angleZ,this.color=color; } Rect.prototype.draw = function(layer){ this.graphics.clear(); this.graphics.drawVertices(1,"#000000",[this.getPoint(this.pointA),this.getPoint(this.pointB),this.getPoint(this.pointC),this.getPoint(this.pointD)],true,this.color); }; Rect.prototype.setAngle = function(a,b){ this.angleX = a; this.angleZ = b; this.z=this.getPoint(this.pointZ)[2]; }; Rect.prototype.getPoint = function(p){ var u2,v2,w2,u=p[0],v=p[1],w=p[2]; u2 = u * Math.cos(this.angleX) - v * Math.sin(this.angleX); v2 = u * Math.sin(this.angleX) + v * Math.cos(this.angleX); w2 = w; u = u2; v = v2; w = w2; u2 = u; v2 = v * Math.cos(this.angleZ) - w * Math.sin(this.angleZ); w2 = v * Math.sin(this.angleZ) + w * Math.cos(this.angleZ); u = u2; v = v2; w = w2; return [u2,v2,w2]; }; 三，Main.js
init(50,"mylegend",400,400,main); var a = 0,b=0,backLayer,step = 20,key = null; function main(){ backLayer = new LSprite(); addChild(backLayer); backLayer.x = 120,backLayer.y = 120; //后 for(var x=0;x<3;x++){ for(var y=0;y<3;y++){ z = 0; var rect = new Rect([-3*step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-step + y*2*step,-3*step + z*2*step],[-3*step + x*2*step,-step + y*2*step,-3*step + z*2*step],0,0,"#FF4500"); backLayer.addChild(rect); } } //前 for(var x=0;x<3;x++){ for(var y=0;y<3;y++){ z = 3; var rect = new Rect([-3*step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-step + y*2*step,-3*step + z*2*step],[-3*step + x*2*step,-step + y*2*step,-3*step + z*2*step],0,0,"#FF0000"); backLayer.addChild(rect); } } //上 for(var x=0;x<3;x++){ for(var z=0;z<3;z++){ y = 0; var rect = new Rect([-3*step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-3*step + y*2*step,-step + z*2*step],[-3*step + x*2*step,-3*step + y*2*step,-step + z*2*step],0,0,"#FFFFFF"); backLayer.addChild(rect); } } //下 for(var x=0;x<3;x++){ for(var z=0;z<3;z++){ y = 3; var rect = new Rect([-3*step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-step + x*2*step,-3*step + y*2*step,-step + z*2*step],[-3*step + x*2*step,-3*step + y*2*step,-step + z*2*step],0,0,"#FFFF00"); backLayer.addChild(rect); } } //左 for(var y=0;y<3;y++){ for(var z=0;z<3;z++){ x = 0; var rect = new Rect([-3*step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-3*step + x*2*step,-3*step + y*2*step,-step + z*2*step],[-3*step + x*2*step,-step + y*2*step,-step + z*2*step],[-3*step + x*2*step,-step + y*2*step,-3*step + z*2*step],0,0,"#008000"); backLayer.addChild(rect); } } //右 for(var y=0;y<3;y++){ for(var z=0;z<3;z++){ x = 3; var rect = new Rect([-3*step + x*2*step,-3*step + y*2*step,-3*step + z*2*step],[-3*step + x*2*step,-3*step + y*2*step,-step + z*2*step],[-3*step + x*2*step,-step + y*2*step,-step + z*2*step],[-3*step + x*2*step,-step + y*2*step,-3*step + z*2*step],0,0,"#0000FF"); backLayer.addChild(rect); } } backLayer.addEventListener(LEvent.ENTER_FRAME,onframe); } function onframe(){ a += 0.1 , b += 0.1; backLayer.childList = backLayer.childList.sort(function(a,b){return a.z - b.z;}); for(key in backLayer.childList){ backLayer.childList[key].setAngle(a,b); backLayer.childList[key].draw(backLayer); } } 這只是一個非常簡陋的3D模型，希望對大家的學習有所幫助，也希望大家多多支持武林網。
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