// Copyright 2012 ESRI
// 
// All rights reserved under the copyright laws of the United States
// and applicable international laws, treaties, and conventions.
// 
// You may freely redistribute and use this sample code, with or
// without modification, provided you include the original copyright
// notice and use restrictions.
// 
// See the use restrictions.
// 

using System;
using System.Windows.Forms;
using ESRI.ArcGIS.Analyst3D;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.GlobeCore;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS;


namespace GlobeNavigation
{
  /// <summary>
  /// Summary description for Form1.
  /// </summary>
  public class Navigation : System.Windows.Forms.Form
  {
    internal System.Windows.Forms.TrackBar TrackBar1;
    public System.Windows.Forms.CheckBox chkSpin;
    public System.Windows.Forms.RadioButton optTools1;
    public System.Windows.Forms.RadioButton optTools0;
    public System.Windows.Forms.Button cmdLoadDocument;
    public System.Windows.Forms.Button cmdZoomOut;
    public System.Windows.Forms.Button cmdZoomIn;
    public System.Windows.Forms.Button cmdFullExtent;
    public System.Windows.Forms.Label Label1;
    public System.Windows.Forms.Label lblNavigate;
    public System.Windows.Forms.Label lblZoom;
    public System.Windows.Forms.Label lblLoad;
    private System.Windows.Forms.OpenFileDialog openFileDialog1;
    
    private ISceneViewer m_ActiveView; 
    private ICamera m_Camera;
    private IPoint m_pMousePos = new PointClass();
    private bool m_bMouseDown;
    private bool m_bZooming = false;
    private double m_dSpinSpeed = 0;
    private double m_dZoom;
    
    const double cMinZoom = 1.00002;
    const double cMaxZoom = 1.1;
    const double cDistanceZoomLimit = 200.0;
    private ESRI.ArcGIS.Controls.AxGlobeControl axGlobeControl1;
    private ESRI.ArcGIS.Controls.AxLicenseControl axLicenseControl1;

    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.Container components = null;

    public Navigation()
    {
      //
      // Required for Windows Form Designer support
      //
      InitializeComponent();

      //
      // TODO: Add any constructor code after InitializeComponent call
      //
    }

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    protected override void Dispose( bool disposing )
    {
            //Release COM objects, check in extension and shutdown
            ESRI.ArcGIS.ADF.COMSupport.AOUninitialize.Shutdown();

      if( disposing )
      {
        if (components != null) 
        {
          components.Dispose();
        }
      }
      base.Dispose( disposing );
    }

    #region Windows Form Designer generated code
    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
      System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(Navigation));
      this.TrackBar1 = new System.Windows.Forms.TrackBar();
      this.chkSpin = new System.Windows.Forms.CheckBox();
      this.optTools1 = new System.Windows.Forms.RadioButton();
      this.optTools0 = new System.Windows.Forms.RadioButton();
      this.cmdLoadDocument = new System.Windows.Forms.Button();
      this.cmdZoomOut = new System.Windows.Forms.Button();
      this.cmdZoomIn = new System.Windows.Forms.Button();
      this.cmdFullExtent = new System.Windows.Forms.Button();
      this.Label1 = new System.Windows.Forms.Label();
      this.lblNavigate = new System.Windows.Forms.Label();
      this.lblZoom = new System.Windows.Forms.Label();
      this.lblLoad = new System.Windows.Forms.Label();
      this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
      this.axGlobeControl1 = new ESRI.ArcGIS.Controls.AxGlobeControl();
      this.axLicenseControl1 = new ESRI.ArcGIS.Controls.AxLicenseControl();
      ((System.ComponentModel.ISupportInitialize)(this.TrackBar1)).BeginInit();
      ((System.ComponentModel.ISupportInitialize)(this.axGlobeControl1)).BeginInit();
      ((System.ComponentModel.ISupportInitialize)(this.axLicenseControl1)).BeginInit();
      this.SuspendLayout();
      // 
      // TrackBar1
      // 
      this.TrackBar1.Location = new System.Drawing.Point(440, 432);
      this.TrackBar1.Name = "TrackBar1";
      this.TrackBar1.Size = new System.Drawing.Size(104, 45);
      this.TrackBar1.TabIndex = 26;
      this.TrackBar1.Scroll += new System.EventHandler(this.TrackBar1_Scroll);
      // 
      // chkSpin
      // 
      this.chkSpin.BackColor = System.Drawing.SystemColors.Control;
      this.chkSpin.Cursor = System.Windows.Forms.Cursors.Default;
      this.chkSpin.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.chkSpin.ForeColor = System.Drawing.SystemColors.ControlText;
      this.chkSpin.Location = new System.Drawing.Point(456, 408);
      this.chkSpin.Name = "chkSpin";
      this.chkSpin.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.chkSpin.Size = new System.Drawing.Size(57, 17);
      this.chkSpin.TabIndex = 25;
      this.chkSpin.Text = "Spin";
      this.chkSpin.Click += new System.EventHandler(this.chkSpin_Click);
      // 
      // optTools1
      // 
      this.optTools1.Appearance = System.Windows.Forms.Appearance.Button;
      this.optTools1.BackColor = System.Drawing.SystemColors.Control;
      this.optTools1.Cursor = System.Windows.Forms.Cursors.Default;
      this.optTools1.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.optTools1.ForeColor = System.Drawing.SystemColors.ControlText;
      this.optTools1.Location = new System.Drawing.Point(448, 328);
      this.optTools1.Name = "optTools1";
      this.optTools1.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.optTools1.Size = new System.Drawing.Size(81, 25);
      this.optTools1.TabIndex = 20;
      this.optTools1.TabStop = true;
      this.optTools1.Text = "Zoom In/Out";
      this.optTools1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
      this.optTools1.Click += new System.EventHandler(this.MixedControls_Click);
      // 
      // optTools0
      // 
      this.optTools0.Appearance = System.Windows.Forms.Appearance.Button;
      this.optTools0.BackColor = System.Drawing.SystemColors.Control;
      this.optTools0.Cursor = System.Windows.Forms.Cursors.Default;
      this.optTools0.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.optTools0.ForeColor = System.Drawing.SystemColors.ControlText;
      this.optTools0.Location = new System.Drawing.Point(448, 288);
      this.optTools0.Name = "optTools0";
      this.optTools0.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.optTools0.Size = new System.Drawing.Size(81, 25);
      this.optTools0.TabIndex = 19;
      this.optTools0.TabStop = true;
      this.optTools0.Text = "Navigate";
      this.optTools0.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
      this.optTools0.Click += new System.EventHandler(this.MixedControls_Click);
      // 
      // cmdLoadDocument
      // 
      this.cmdLoadDocument.BackColor = System.Drawing.SystemColors.Control;
      this.cmdLoadDocument.Cursor = System.Windows.Forms.Cursors.Default;
      this.cmdLoadDocument.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.cmdLoadDocument.ForeColor = System.Drawing.SystemColors.ControlText;
      this.cmdLoadDocument.Location = new System.Drawing.Point(456, 48);
      this.cmdLoadDocument.Name = "cmdLoadDocument";
      this.cmdLoadDocument.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.cmdLoadDocument.Size = new System.Drawing.Size(67, 25);
      this.cmdLoadDocument.TabIndex = 18;
      this.cmdLoadDocument.Text = "Load ...";
      this.cmdLoadDocument.Click += new System.EventHandler(this.cmdLoadDocument_Click);
      // 
      // cmdZoomOut
      // 
      this.cmdZoomOut.BackColor = System.Drawing.SystemColors.Control;
      this.cmdZoomOut.Cursor = System.Windows.Forms.Cursors.Default;
      this.cmdZoomOut.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.cmdZoomOut.ForeColor = System.Drawing.SystemColors.ControlText;
      this.cmdZoomOut.Location = new System.Drawing.Point(440, 168);
      this.cmdZoomOut.Name = "cmdZoomOut";
      this.cmdZoomOut.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.cmdZoomOut.Size = new System.Drawing.Size(99, 25);
      this.cmdZoomOut.TabIndex = 17;
      this.cmdZoomOut.Text = "Fixed Zoom Out";
      this.cmdZoomOut.Click += new System.EventHandler(this.cmdZoomOut_Click);
      // 
      // cmdZoomIn
      // 
      this.cmdZoomIn.BackColor = System.Drawing.SystemColors.Control;
      this.cmdZoomIn.Cursor = System.Windows.Forms.Cursors.Default;
      this.cmdZoomIn.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.cmdZoomIn.ForeColor = System.Drawing.SystemColors.ControlText;
      this.cmdZoomIn.Location = new System.Drawing.Point(440, 136);
      this.cmdZoomIn.Name = "cmdZoomIn";
      this.cmdZoomIn.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.cmdZoomIn.Size = new System.Drawing.Size(99, 25);
      this.cmdZoomIn.TabIndex = 16;
      this.cmdZoomIn.Text = "Fixed Zoom In";
      this.cmdZoomIn.Click += new System.EventHandler(this.cmdZoomIn_Click);
      // 
      // cmdFullExtent
      // 
      this.cmdFullExtent.BackColor = System.Drawing.SystemColors.Control;
      this.cmdFullExtent.Cursor = System.Windows.Forms.Cursors.Default;
      this.cmdFullExtent.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.cmdFullExtent.ForeColor = System.Drawing.SystemColors.ControlText;
      this.cmdFullExtent.Location = new System.Drawing.Point(440, 200);
      this.cmdFullExtent.Name = "cmdFullExtent";
      this.cmdFullExtent.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.cmdFullExtent.Size = new System.Drawing.Size(99, 25);
      this.cmdFullExtent.TabIndex = 15;
      this.cmdFullExtent.Text = "Full Extent";
      this.cmdFullExtent.Click += new System.EventHandler(this.cmdFullExtent_Click);
      // 
      // Label1
      // 
      this.Label1.BackColor = System.Drawing.SystemColors.Control;
      this.Label1.Cursor = System.Windows.Forms.Cursors.Default;
      this.Label1.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.Label1.ForeColor = System.Drawing.SystemColors.Highlight;
      this.Label1.Location = new System.Drawing.Point(440, 360);
      this.Label1.Name = "Label1";
      this.Label1.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.Label1.Size = new System.Drawing.Size(97, 49);
      this.Label1.TabIndex = 24;
      this.Label1.Text = "Control the spin speed with the slider.";
      // 
      // lblNavigate
      // 
      this.lblNavigate.BackColor = System.Drawing.SystemColors.Control;
      this.lblNavigate.Cursor = System.Windows.Forms.Cursors.Default;
      this.lblNavigate.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.lblNavigate.ForeColor = System.Drawing.SystemColors.Highlight;
      this.lblNavigate.Location = new System.Drawing.Point(440, 232);
      this.lblNavigate.Name = "lblNavigate";
      this.lblNavigate.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.lblNavigate.Size = new System.Drawing.Size(105, 49);
      this.lblNavigate.TabIndex = 23;
      this.lblNavigate.Text = "Use the option buttons to select a navigation tool. ";
      // 
      // lblZoom
      // 
      this.lblZoom.BackColor = System.Drawing.SystemColors.Control;
      this.lblZoom.Cursor = System.Windows.Forms.Cursors.Default;
      this.lblZoom.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.lblZoom.ForeColor = System.Drawing.SystemColors.Highlight;
      this.lblZoom.Location = new System.Drawing.Point(440, 80);
      this.lblZoom.Name = "lblZoom";
      this.lblZoom.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.lblZoom.Size = new System.Drawing.Size(104, 49);
      this.lblZoom.TabIndex = 22;
      this.lblZoom.Text = "Use the buttons to navigate the Globe data.";
      // 
      // lblLoad
      // 
      this.lblLoad.BackColor = System.Drawing.SystemColors.Control;
      this.lblLoad.Cursor = System.Windows.Forms.Cursors.Default;
      this.lblLoad.Font = new System.Drawing.Font("Tahoma", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
      this.lblLoad.ForeColor = System.Drawing.SystemColors.Highlight;
      this.lblLoad.Location = new System.Drawing.Point(440, 8);
      this.lblLoad.Name = "lblLoad";
      this.lblLoad.RightToLeft = System.Windows.Forms.RightToLeft.No;
      this.lblLoad.Size = new System.Drawing.Size(97, 33);
      this.lblLoad.TabIndex = 21;
      this.lblLoad.Text = "Browse to a 3dd file to load.";
      // 
      // axGlobeControl1
      // 
      this.axGlobeControl1.Location = new System.Drawing.Point(8, 8);
      this.axGlobeControl1.Name = "axGlobeControl1";
      this.axGlobeControl1.OcxState = ((System.Windows.Forms.AxHost.State)(resources.GetObject("axGlobeControl1.OcxState")));
      this.axGlobeControl1.Size = new System.Drawing.Size(424, 464);
      this.axGlobeControl1.TabIndex = 27;
      this.axGlobeControl1.OnMouseDown += new ESRI.ArcGIS.Controls.IGlobeControlEvents_Ax_OnMouseDownEventHandler(this.axGlobeControl1_OnMouseDown);
      this.axGlobeControl1.OnMouseMove += new ESRI.ArcGIS.Controls.IGlobeControlEvents_Ax_OnMouseMoveEventHandler(this.axGlobeControl1_OnMouseMove);
      this.axGlobeControl1.OnMouseUp += new ESRI.ArcGIS.Controls.IGlobeControlEvents_Ax_OnMouseUpEventHandler(this.axGlobeControl1_OnMouseUp);
      // 
      // axLicenseControl1
      // 
      this.axLicenseControl1.Enabled = true;
      this.axLicenseControl1.Location = new System.Drawing.Point(216, 24);
      this.axLicenseControl1.Name = "axLicenseControl1";
      this.axLicenseControl1.OcxState = ((System.Windows.Forms.AxHost.State)(resources.GetObject("axLicenseControl1.OcxState")));
      this.axLicenseControl1.Size = new System.Drawing.Size(200, 50);
      this.axLicenseControl1.TabIndex = 28;
      // 
      // Form1
      // 
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(552, 478);
      this.Controls.Add(this.axLicenseControl1);
      this.Controls.Add(this.axGlobeControl1);
      this.Controls.Add(this.TrackBar1);
      this.Controls.Add(this.chkSpin);
      this.Controls.Add(this.optTools1);
      this.Controls.Add(this.optTools0);
      this.Controls.Add(this.cmdLoadDocument);
      this.Controls.Add(this.cmdZoomOut);
      this.Controls.Add(this.cmdZoomIn);
      this.Controls.Add(this.cmdFullExtent);
      this.Controls.Add(this.Label1);
      this.Controls.Add(this.lblNavigate);
      this.Controls.Add(this.lblZoom);
      this.Controls.Add(this.lblLoad);
      this.Name = "Form1";
      this.Text = "Form1";
      this.Load += new System.EventHandler(this.Form1_Load);
      ((System.ComponentModel.ISupportInitialize)(this.TrackBar1)).EndInit();
      ((System.ComponentModel.ISupportInitialize)(this.axGlobeControl1)).EndInit();
      ((System.ComponentModel.ISupportInitialize)(this.axLicenseControl1)).EndInit();
      this.ResumeLayout(false);

    }
    #endregion

    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main() 
    {
            
            if (!RuntimeManager.Bind(ProductCode.Engine))
            {
                if (!RuntimeManager.Bind(ProductCode.Desktop))
                {
                    MessageBox.Show("Unable to bind to ArcGIS runtime. Application will be shut down.");
                    return;
                }
            }

            Application.Run(new Navigation());
    }

    private void Form1_Load(object sender, System.EventArgs e)
    {
      //Initialize member variables
      m_ActiveView = axGlobeControl1.GlobeDisplay.ActiveViewer;
      m_Camera = m_ActiveView.Camera;
    }

    private void cmdLoadDocument_Click(object sender, System.EventArgs e)
    {
      //Open a file dialog for selecting map documents
      openFileDialog1.Title = "Globe Documents";
      openFileDialog1.DefaultExt = ".3dd";
      openFileDialog1.Filter = "Globe Document(*.3dd)|*.3dd";
      openFileDialog1.ShowDialog();

      //Check a file is selected and that it's a valid Globe document
      //before attempting to load it
      if (openFileDialog1.FileName != "")
      {
        if (axGlobeControl1.Check3dFile(openFileDialog1.FileName) == true)
        {
          axGlobeControl1.Load3dFile(openFileDialog1.FileName);
        }
        else
        {
          MessageBox.Show("Cannot load " + openFileDialog1.FileName);
        }
      }
    }

    private void cmdFullExtent_Click(object sender, System.EventArgs e)
    {
      IGlobeCamera camera = (IGlobeCamera) m_Camera;

      //Make sure that the camera is using global coordinates
      camera.OrientationMode = esriGlobeCameraOrientationMode.esriGlobeCameraOrientationGlobal;

      //Point the camera at 0,0 in lat,long - this is the default target
      IPoint target = new PointClass();
      target.PutCoords(0.0, 0.0);
      target.Z = 0.0;
      m_Camera.Target = target;

      //Reset the camera to its default values
      m_Camera.Azimuth = 140;
      m_Camera.Inclination = 45;
      m_Camera.ViewingDistance = 4.0;
      m_Camera.ViewFieldAngle = 30.0;
      m_Camera.RollAngle = 0.0;
      m_Camera.RecalcUp();
      m_ActiveView.Redraw(false);
    }

    private void cmdZoomIn_Click(object sender, System.EventArgs e)
    {
      //Reset the camera field of view angle to 0.9 of its previous value
      double vfa = m_Camera.ViewFieldAngle;
      m_Camera.ViewFieldAngle = vfa * 0.9;
      m_ActiveView.Redraw(false);
    }

    private void cmdZoomOut_Click(object sender, System.EventArgs e)
    {
      //Reset the camera field of view angle to 1.1 times its previous value
      double vfa = m_Camera.ViewFieldAngle;
      m_Camera.ViewFieldAngle = vfa * 1.1;
      m_ActiveView.Redraw(false);
    }

    private void CalculateMoveFactors(double dist)
    {
      bool bIsAtCenter;
      int indexGlobe;

      //See if the camera is pointing at the center of the globe.
      IGlobeViewer globeViewer = (IGlobeViewer) m_ActiveView;
      globeViewer.GetIsTargetAtCenter(out bIsAtCenter, out indexGlobe);

      //If the camera is pointing at the center of the globe then the zoom speed
      //depends on how far away it is, otherwise the zoom factor is fixed. As the
      //camera approaches the globe surface (where dist = 1) the zoom speed slows
      //down. The other factors were worked out by trial and error.
      if (bIsAtCenter == true)
      {
        m_dZoom = cMinZoom + (cMaxZoom - cMinZoom) * (dist - 1.0) / 3.0;
      }
      else
      {
        m_dZoom = 1.1;
      }
    }

    private void chkSpin_Click(object sender, System.EventArgs e)
    {
      if (chkSpin.CheckState == CheckState.Checked)
            {
        axGlobeControl1.GlobeViewer.StartSpinning(esriGlobeSpinDirection.esriCounterClockwise);
        axGlobeControl1.GlobeViewer.SpinSpeed = 3;
        TrackBar1.Enabled = true;
        m_dSpinSpeed = 3;
      }
      else
      {
        axGlobeControl1.GlobeViewer.StopSpinning();
        TrackBar1.Enabled = false;
        m_dSpinSpeed = 0;
      }
    }

    private void TrackBar1_Scroll(object sender, System.EventArgs e)
    {
      //The globe should increase its spin speed with every increment greater than
      //5 and decrease it for every increment less.
      int sliderPos = (TrackBar1.Value - 5);
      if (sliderPos == 0)
      {
        m_dSpinSpeed = 3;
      }
      else if (sliderPos > 0) 
      {
        m_dSpinSpeed = 3 * (sliderPos + 1);
      }
      else
      {
        m_dSpinSpeed = 3 / (1 - sliderPos);
      }

      axGlobeControl1.GlobeViewer.SpinSpeed = m_dSpinSpeed;
    }

    private void MixedControls_Click(object sender, System.EventArgs e)
    {
      RadioButton b = (RadioButton) sender;
      //Set current tool
      switch (b.Name)
      {
        case "optTools0":
          m_bZooming = false;
          axGlobeControl1.Navigate = true;
          axGlobeControl1.MousePointer = esriControlsMousePointer.esriPointerDefault;
          break;
        case "optTools1":
          m_bZooming = true;
          axGlobeControl1.Navigate = false;
          axGlobeControl1.MousePointer = esriControlsMousePointer.esriPointerZoom;
          break;
      }
    }

    private void axGlobeControl1_OnMouseUp(object sender, ESRI.ArcGIS.Controls.IGlobeControlEvents_OnMouseUpEvent e)
    {
      //Cancel the zoom operation
      m_bMouseDown = false;
      //Navigate can cancel spin - make sure it starts again
      if (m_dSpinSpeed > 0)
      {
        axGlobeControl1.GlobeViewer.StartSpinning(esriGlobeSpinDirection.esriCounterClockwise);
      }
    }

    private void axGlobeControl1_OnMouseMove(object sender, ESRI.ArcGIS.Controls.IGlobeControlEvents_OnMouseMoveEvent e)
    {
      if (m_bMouseDown == false)
      {
        return;
      }

      //If we're in a zoom operation then
      //Get the difference in mouse position between this and the last one
      double dx = e.x - m_pMousePos.X;
      double dy = e.y - m_pMousePos.Y;
      if ((dx == 0) & (dy == 0)) 
      {
        return;             
      }

      //Work out how far the observer is currently from the globe and use this
      //distance to determine how far to move
      IPoint observer = m_Camera.Observer;
      double zObs;
      double xObs; 
      double yObs;
      double dist; 
      observer.QueryCoords(out xObs, out yObs);
      zObs = observer.Z;
      dist = System.Math.Sqrt(xObs * xObs + yObs * yObs + zObs * zObs);
      CalculateMoveFactors(dist);

      //Zoom out and in as the mouse moves up and down the screen respectively
      if ((dy < 0) & (dist < cDistanceZoomLimit)) 
      {
        m_Camera.Zoom(m_dZoom);
      }
      else if (dy > 0) 
      {
        m_Camera.Zoom((1 / m_dZoom));
      }

      m_pMousePos.X = e.x;
      m_pMousePos.Y = e.y;
      m_ActiveView.Redraw(false);
    }

    private void axGlobeControl1_OnMouseDown(object sender, ESRI.ArcGIS.Controls.IGlobeControlEvents_OnMouseDownEvent e)
    {
      //Mouse down should initiate a zoom only if the Zoom check box is checked
      if (m_bZooming == false)
      {
        return;
      }

      if (e.button == 1)
      {
        m_bMouseDown = true;
        m_pMousePos.X = e.x;
        m_pMousePos.Y = e.y;
      }
    }

  }
}