[WorldWind学习]6.World类

最新推荐文章于 2023-07-08 15:40:54 发布

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最新推荐文章于 2023-07-08 15:40:54 发布

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本文深入探讨了World对象在WorldWind中的核心作用，包括渲染对象集合及关键渲染方法、更新方法和选择行动方法的工作原理。

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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         }