[WorldWind学习]2.WorldWindow控件

首先查看WorldWindow 的构造函数，接着查看InitializeGraphics()函数。

public WorldWindow()
        {
            this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.Opaque, true);

            // The m_Device3d can't be created unless the control is at least 1 x 1 pixels in size
            this.Size = new Size(1,1);

            try
            {
                // Now perform the rendering m_Device3d initialization
                // Skip DirectX initialization in design mode
                if(!IsInDesignMode())
                    this.InitializeGraphics();//初始化设备Device

                //Post m_Device3d creation initialization
                this.drawArgs = new DrawArgs(m_Device3d, this );
                this.m_RootWidget = new WorldWind.Widgets.RootWidget(this);
                this.m_NewRootWidget = new WorldWind.NewWidgets.RootWidget(this);

                //this.m_RootWidget.ChildWidgets.Add(layerManager);
                DrawArgs.RootWidget = this.m_RootWidget;
                DrawArgs.NewRootWidget = this.m_NewRootWidget;

                m_FpsTimer.Elapsed += new System.Timers.ElapsedEventHandler(m_FpsTimer_Elapsed);
                m_FpsTimer.Start();

                TimeKeeper.Start();
            //    WorldWind.Widgets.LayerManager layerManager = new WorldWind.Widgets.LayerManager();
            //    m_RootWidget.ChildWidgets.Add(layerManager);

            }
            catch (InvalidCallException caught)
            {
                throw new InvalidCallException(
                    "Unable to locate a compatible graphics adapter. Make sure you are running the latest version of DirectX.", caught );
            }
            catch (NotAvailableException caught)
            {
                throw new NotAvailableException(
                    "Unable to locate a compatible graphics adapter. Make sure you are running the latest version of DirectX.", caught );
            }
        }

private void InitializeGraphics()
        {
            // Set up our presentation parameters
            m_presentParams = new PresentParameters();

            m_presentParams.Windowed = true;
            m_presentParams.SwapEffect = SwapEffect.Discard;
            m_presentParams.AutoDepthStencilFormat = DepthFormat.D16;
            m_presentParams.EnableAutoDepthStencil = true;
            
            if(!World.Settings.VSync)
                // Disable wait for vertical retrace (higher frame rate at the expense of tearing)
                m_presentParams.PresentationInterval = PresentInterval.Immediate;

            int adapterOrdinal = 0;
            try
            {
                // Store the default adapter
                adapterOrdinal = Manager.Adapters.Default.Adapter;
            }
            catch
            {
                // User probably needs to upgrade DirectX or install a 3D capable graphics adapter
                throw new NotAvailableException();
            }

            DeviceType dType = DeviceType.Hardware;

            foreach(AdapterInformation ai in Manager.Adapters)
            {
                if(ai.Information.Description.IndexOf("NVPerfHUD") >= 0)
                {
                    adapterOrdinal = ai.Adapter;
                    dType = DeviceType.Reference;
                }
            }
            CreateFlags flags = CreateFlags.SoftwareVertexProcessing;

            // Check to see if we can use a pure hardware m_Device3d
            Caps caps = Manager.GetDeviceCaps(adapterOrdinal, DeviceType.Hardware);

            // Do we support hardware vertex processing?
            if(caps.DeviceCaps.SupportsHardwareTransformAndLight)
                //    // Replace the software vertex processing
                flags = CreateFlags.HardwareVertexProcessing;

            // Use multi-threading for now - TODO: See if the code can be changed such that this isn't necessary (Texture Loading for example)
            flags |= CreateFlags.MultiThreaded | CreateFlags.FpuPreserve;

            try
            {
                // Create our m_Device3d
                m_Device3d = new Device(adapterOrdinal, dType, this, flags, m_presentParams);
            }
            catch( Microsoft.DirectX.DirectXException    )
            {
                throw new NotSupportedException("Unable to create the Direct3D m_Device3d.");
            }

            // Hook the m_Device3d reset event
            m_Device3d.DeviceReset += new EventHandler(OnDeviceReset);
            m_Device3d.DeviceResizing += new CancelEventHandler(m_Device3d_DeviceResizing);
            OnDeviceReset(m_Device3d, null);
        }

控件重要的方法：

OnApplicationIdle函数定义：
public void OnApplicationIdle(object sender, EventArgs e)//The world render loop.实现世界的渲染循环
OnPaint函数定义：
protected override void OnPaint(PaintEventArgs e)    // Occurs when the control is redrawn and m_isRenderDisabled=true.
protected override void OnMouseWheel(MouseEventArgs e)  //处理鼠标滚轮事件
protected override void OnKeyDown(KeyEventArgs e)  //重载处理键盘按下的事件
protected override void OnKeyUp(KeyEventArgs e)     //重载处理键盘弹起事件
protected override void OnMouseDoubleClick(MouseEventArgs e)
protected override void OnMouseUp(MouseEventArgs e)

控件几个重要的属性和字段：

  private Device m_Device3d;
  private DrawArgs drawArgs;
  private World m_World;
  private Cache m_Cache;
  private Thread m_WorkerThread;