[ActionScript 3.0] AS3 绘制正八面体（线条）

分析：

将八面体置于3D坐标系中，其中心的坐标位于原点（0，0，0），让八面体的六个顶点恰好位于3D坐标系的x轴、y轴和z轴上，则从八面体的中心到这六个顶点的距离是相等的。我们可以假设这个距离为r，则六个顶点的坐标分别为上（0，-r，0）、下（0，r，0）、四周：左（-r，0，0）、右（r，0，0）、前（0，0，-r）、后（0，0，r）。

 1 package
 2 {
 3     import flash.display.MovieClip;
 4     import flash.display.Sprite;
 5     import flash.events.Event;
 6     import flash.geom.Point;
 7     import flash.geom.Vector3D;
 8     
 9     /**
10      * @author Frost.Yen
11      * @E-mail 871979853@qq.com
12      * @create 2015-9-7 下午5:10:05
13      *
14      */
15     [SWF(width="800",height="600")]
16     public class LineOctahedron extends Sprite
17     {
18         private var _faceArr:Array = [];
19         private var _r:Number = 100;//中心到顶点的距离
20         private var _focus:Number = 200;//焦距
21         private var _lineContainer:Sprite;
22         private var _container:Sprite;
23         private var _vertexArr:Array = [{x:0,y:_r,z:0},{x:-_r,y:0,z:0},{x:0,y:0,z:_r},{x:_r,y:0,z:0},{x:0,y:0,z:-_r},{x:0,y:-_r,z:0}];
24         public function LineOctahedron()
25         {
26             initViews();
27             initEventListeners();
28         }
29         private function initViews():void
30         {
31             _container = new Sprite();
32             _lineContainer = new Sprite();
33             _container.x = _lineContainer.x = 400;
34             _container.y = _lineContainer.y = 300;
35             this.addChild(_container);
36             this.addChild(_lineContainer);
37             createFace();
38             
39         }
40         private function initEventListeners():void
41         {
42             this.addEventListener(Event.ENTER_FRAME,onEnterFrame);
43         }
44         private function onEnterFrame(e:Event):void
45         {
46             for (var i:int=0; i<_faceArr.length; i++)
47             {
48                 _faceArr[i].transform.matrix3D.appendRotation((mouseX-_lineContainer.x)/50,Vector3D.Y_AXIS);
49                 _faceArr[i].transform.matrix3D.appendRotation((mouseY-_lineContainer.y)/50,Vector3D.X_AXIS);
50                 _faceArr[i].Z = (_faceArr[i] as MovieClip).transform.getRelativeMatrix3D(_container).position.z;
51                 _faceArr[i].X = (_faceArr[i] as MovieClip).transform.getRelativeMatrix3D(_container).position.x*(_focus/(_focus+_faceArr[i].Z));
52                 _faceArr[i].Y = (_faceArr[i] as MovieClip).transform.getRelativeMatrix3D(_container).position.y*(_focus/(_focus+_faceArr[i].Z));
53                 //利用焦距实现透视
54             }
55             _lineContainer.graphics.clear();
56             _lineContainer.graphics.lineStyle(3,0x00ffff);
57             for(i = 1;i<=4;i++){
58                 //从上面连到四周;
59                 _lineContainer.graphics.moveTo(_faceArr[0].X,_faceArr[0].Y);
60                 _lineContainer.graphics.lineTo(_faceArr[i].X,_faceArr[i].Y);
61                 //从下面连到四周;
62                 _lineContainer.graphics.moveTo(_faceArr[5].X,_faceArr[5].Y);
63                 _lineContainer.graphics.lineTo(_faceArr[i].X,_faceArr[i].Y);
64                 //四周顶点互连;
65                 _lineContainer.graphics.moveTo(_faceArr[i].X,_faceArr[i].Y);
66                 _lineContainer.graphics.lineTo(_faceArr[i!=4?i+1:1].X,_faceArr[i!=4?i+1:1].Y);
67             }
68         }
69         private function createFace():void
70         {
71             for(var i:int = 0;i<6;i++){
72                 var mc:MovieClip = new MovieClip();
73                 _container.addChild(mc);
74                 _faceArr.push(mc);
75                 mc.x = _vertexArr[i].x;
76                 mc.y = _vertexArr[i].y;
77                 mc.z = _vertexArr[i].z;
78             }
79         }
80     }
81 }