[WorldWind学习]6.World类

public class World : RenderableObject

World对象是WW中最重要的对象，他包含了一个渲染对象的集合，同时他自身也是一个渲染对象。

重载的Render方法：

 1  public override void Render(DrawArgs drawArgs)

 2         {

 3             try

 4             {

 5 

 6                 if (m_WorldSurfaceRenderer != null && World.Settings.UseWorldSurfaceRenderer)

 7                 {

 8                     m_WorldSurfaceRenderer.RenderSurfaceImages(drawArgs);

 9                 }

10 

11                 //  Old method -- problems with RenderPriority sorting

12                 //    RenderableObjects.Render(drawArgs);

13 

14                 RenderStars(drawArgs, RenderableObjects);

15 

16                 if (drawArgs.CurrentWorld.IsEarth && World.Settings.EnableAtmosphericScattering)

17                 {

18                     float aspectRatio = (float)drawArgs.WorldCamera.Viewport.Width / drawArgs.WorldCamera.Viewport.Height;

19                     float zNear = (float)drawArgs.WorldCamera.Altitude * 0.1f;

20                     double distToCenterOfPlanet = (drawArgs.WorldCamera.Altitude + equatorialRadius);

21                     double tangentalDistance = Math.Sqrt(distToCenterOfPlanet * distToCenterOfPlanet - equatorialRadius * equatorialRadius);

22                     double amosphereThickness = Math.Sqrt(m_outerSphere.m_radius * m_outerSphere.m_radius + equatorialRadius * equatorialRadius);

23                     Matrix proj = drawArgs.device.Transform.Projection;

24                     drawArgs.device.Transform.Projection = Matrix.PerspectiveFovRH((float)drawArgs.WorldCamera.Fov.Radians, aspectRatio, zNear, (float)(tangentalDistance + amosphereThickness));

25                     drawArgs.device.RenderState.ZBufferEnable = false;

26                     drawArgs.device.RenderState.CullMode = Cull.CounterClockwise;

27                     m_outerSphere.Render(drawArgs);

28                     drawArgs.device.RenderState.CullMode = Cull.Clockwise;

29                     drawArgs.device.RenderState.ZBufferEnable = true;

30 

31                     drawArgs.device.Transform.Projection = proj;

32                 }

33 

34                 if (World.Settings.EnableSunShading)

35                     RenderSun(drawArgs);

36 

37                 //render SurfaceImages

38                 Render(RenderableObjects, WorldWind.Renderable.RenderPriority.TerrainMappedImages, drawArgs);

39 

40                 if (m_projectedVectorRenderer != null)

41                     m_projectedVectorRenderer.Render(drawArgs);

42 

43                 //render AtmosphericImages

44                 Render(RenderableObjects, WorldWind.Renderable.RenderPriority.AtmosphericImages, drawArgs);

45 

46                 //render LinePaths

47                 Render(RenderableObjects, WorldWind.Renderable.RenderPriority.LinePaths, drawArgs);

48 

49                 //render Placenames

50                 Render(RenderableObjects, WorldWind.Renderable.RenderPriority.Placenames, drawArgs);

51 

52                 //render Icons

53                 Render(RenderableObjects, WorldWind.Renderable.RenderPriority.Icons, drawArgs);

54 

55                 //render Custom

56                 Render(RenderableObjects, WorldWind.Renderable.RenderPriority.Custom, drawArgs);

57 

58                 if (Settings.showPlanetAxis)

59                     this.DrawAxis(drawArgs);

60             }

61             catch (Exception ex)

62             {

63                 Log.Write(ex);

64             }

65         }

其中多次调用的Render私有方法：

 1 private void Render(WorldWind.Renderable.RenderableObject renderable, WorldWind.Renderable.RenderPriority priority, DrawArgs drawArgs)

 2         {

 3             if (!renderable.IsOn || (renderable.Name != null && renderable.Name.Equals("Starfield")))

 4                 return;

 5 

 6             try

 7             {

 8                 if (priority == WorldWind.Renderable.RenderPriority.Icons && renderable is Icons)

 9                 {

10                     renderable.Render(drawArgs);

11                 }

12                 else if (renderable is WorldWind.Renderable.RenderableObjectList)

13                 {

14                     WorldWind.Renderable.RenderableObjectList rol = (WorldWind.Renderable.RenderableObjectList)renderable;

15                     for (int i = 0; i < rol.ChildObjects.Count; i++)

16                     {

17                         Render((WorldWind.Renderable.RenderableObject)rol.ChildObjects[i], priority, drawArgs);

18                     }

19                 }

20                 // hack at the moment

21                 else if (priority == WorldWind.Renderable.RenderPriority.TerrainMappedImages)

22                 {

23                     if (renderable.RenderPriority == WorldWind.Renderable.RenderPriority.SurfaceImages || renderable.RenderPriority == WorldWind.Renderable.RenderPriority.TerrainMappedImages)

24                     {

25                         renderable.Render(drawArgs);

26                     }

27                 }

28                 else if (renderable.RenderPriority == priority)

29                 {

30                     renderable.Render(drawArgs);

31                 }

32             }

33             catch (Exception ex)

34             {

35                 Log.Write(ex);

36             }

37         }

重载的Update方法：

 1   public override void Update(DrawArgs drawArgs)

 2         {

 3             if (!this.isInitialized)

 4             {

 5                 this.Initialize(drawArgs);

 6             }

 7 

 8             if (this.RenderableObjects != null)

 9             {

10                 this.RenderableObjects.Update(drawArgs);

11             }

12             if (this.m_WorldSurfaceRenderer != null)

13             {

14                 this.m_WorldSurfaceRenderer.Update(drawArgs);

15             }

16 

17             if (this.m_projectedVectorRenderer != null)

18             {

19                 this.m_projectedVectorRenderer.Update(drawArgs);

20             }

21 

22             if (this.TerrainAccessor != null)

23             {

24                 if (drawArgs.WorldCamera.Altitude < 300000)

25                 {

26                     if (System.DateTime.Now - this.lastElevationUpdate > TimeSpan.FromMilliseconds(500))

27                     {

28                         drawArgs.WorldCamera.TerrainElevation = (short)this.TerrainAccessor.GetElevationAt(drawArgs.WorldCamera.Latitude.Degrees, drawArgs.WorldCamera.Longitude.Degrees, 100.0 / drawArgs.WorldCamera.ViewRange.Degrees);

29                         this.lastElevationUpdate = System.DateTime.Now;

30                     }

31                 }

32                 else

33                     drawArgs.WorldCamera.TerrainElevation = 0;

34             }

35             else

36             {

37                 drawArgs.WorldCamera.TerrainElevation = 0;

38             }

39 

40             if (World.Settings.EnableAtmosphericScattering && m_outerSphere != null)

41                 m_outerSphere.Update(drawArgs);

42         }

重载的PerformSelectionAction方法：

1 public override bool PerformSelectionAction(DrawArgs drawArgs)

2         {

3             return this._renderableObjects.PerformSelectionAction(drawArgs);

4         }