【HTML5】3D模型--百行代码实现旋转立体魔方实例 -H5教程

最近研究魔方的玩法，就突然想用HMTL5写一个魔方的模型，由于魔方是一个3D的立方体，这次就试着用HTML5写了一个简单的3D模型。

下面是预览画面。

制作流程

首先你需要下载Html5开源库件lufylegend-1.4.0

魔方分为6个面，每个面由9个小矩形组成，现在我把每个小矩形当做一个类封装起来，

因为现在建立的是一个3D魔方，所以要画出每个小矩形，需要知道小矩形的4个定点，而这4个定点会根据空间的旋转角度而变换，所以为了计算出这4个定点坐标，需要知道魔方绕x轴和z轴旋转的角度。

所以，建立矩形类如下

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是小矩形的四个顶点，angleX,angleZ分别是x轴和z轴旋转的角度，color是小矩形的颜色。

魔方分为6个面，先看一下最前面的一面，如果以立方体的中心作为3D坐标系的中心，那么9个小矩形的各个定点所对应的坐标如下图所示

所以，前面这个面的9个小矩形可以由下面的代码来建立

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是一个LSprite类，step是半个小矩形的长，同样的道理，可以也得到其他5个面。

6个面都建立了，在绘制这6个面之前，首先要根据旋转的角度来计算各个定点的坐标，看下面的图

根据上面的图，用下面的公式即可得到变换后的定点坐标

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];  
};

最后根据小矩形的四个定点坐标，来绘制这个矩形，

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库件中LGraphics类的一个方法，它可以根据传入的定点坐标数组来绘制一个多边形。

最后，给出完整代码，代码很少，JS代码一共91行。

一，index.html

<!DOCTYPE html>  
<html>  
<head>  
<meta charset="UTF-8">  
<title>3D魔方</title>  
</head>  
<body>  
<p id="mylegend">loading……</p>  
<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类

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);  
   }  
}

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