Skyline实现橡皮筋效果绘制矩形框

1         //计算矩形对角点的夹角
2         private double GetAngle(IPosition6 Poi)
3         {       
4             var includeAngle = _sgworld.CoordServices.GetAimingAngles(_Position, Poi);
5             var angle = includeAngle.Yaw - 90 - _Position.Yaw;
6             return (angle / 180 * 3.14);
7         }

 1         SGWorld _sgworld = Application3D.SGworld;
 2         private ITerrainPolygon6 _TerrainRctg;
 3         private IPosition6 _Position;
 4               public ITerrainPolygon6 TerrainRectangle
 5         {
 6             get { return _TerrainRctg; }
 7         }
 8   
 9          //左键开始绘制长方形
10         public bool OnLButtonDown(int Flags, int X, int Y)
11         {
12             if(_Position ==null)
13             {
14                 var wpi = _sgworld.Window.PixelToWorld(X, Y, WorldPointType.WPT_DEFAULT);             
15                 _Position = wpi.Position;
16                 _Position.Yaw = _sgworld.Navigate.GetPosition(AltitudeTypeCode.ATC_TERRAIN_ABSOLUTE).Yaw;                          
17             }
18             else
19             {            
20                 //第二次点击结束绘制  
21                 FinshEdit();                         
22             }
23             return false;
24         }
25 
26        //鼠标移动
27         public void OnFrame()
28         {
29             //创建或更新长方形
30             if (_Position == null) return;
31 
32             var mi = _sgworld.Window.GetMouseInfo();
33             var position = _sgworld.Window.PixelToWorld(mi.X, mi.Y, WorldPointType.WPT_DEFAULT).Position;
34             var length = _Position.DistanceTo(position);
35             var angle = GetAngle(position);
36             var width = Math.Sin(angle) * length;  /*这里矩形的宽就得到了*/
37 
38             var poi1 = _Position.Move(width * -1, _Position.Yaw, 0);  /*两个对角点沿摄像机方向延伸一个宽度*/
39             var poi2 = position.Move(width, _Position.Yaw, 0);
40 
41             var array = new double[] {_Position .X,_Position .Y,1,
42                                      poi1 .X ,poi1 .Y ,1,
43                                      position .X ,position .Y ,1,
44                                      poi2 .X ,poi2 .Y ,1};
45             var cRing = _sgworld.Creator.GeometryCreator.CreateLinearRingGeometry(array);
46             var cPolygonGeometry = _sgworld.Creator.GeometryCreator.CreatePolygonGeometry(cRing, null);
47 
48             if (_TerrainRctg == null)
49             {
50                 var nLineColor = 0xFF00FF00;
51                 var nFillColor = 0xBB00FFFF;
52                 var eAltitudeTypeCode = AltitudeTypeCode.ATC_TERRAIN_RELATIVE;
53                 _TerrainRctg = _sgworld.Creator.CreatePolygon(cPolygonGeometry, nLineColor, nFillColor, eAltitudeTypeCode, parentID, "选中区域");
54             }
55             else
56             {
57                 _TerrainRctg.Geometry = cPolygonGeometry;
58             }
59         }