How to draw mouse feedback on the globe using direct OpenGL plug-in

In this topic

• Drawing mouse feedback on the globe
• Implementing OnAfterDraw event handler

Drawing mouse feedback on the globe

1. Start Visual Studio. In the Solution Explorer, add a new ArcGIS tool. Use the Visual Studio .NET IDE integration framework to implement a BaseTool for ArcGlobe and GlobeControl.
2. Add references to your OpenGL wrapper library and to the ESRI GlobeCore and Analyst3D assemblies. For more information, see How to get and install an OpenGL wrapper for .NET.
3. In your class, set member variables for the IGlobeDisplay, IGlobeViewUtil, and ISceneViewer interfaces. Set member variables to store mouse coordinates and a Boolean flag that indicates whether the mouse key is pressed down. See the following code example:
   

private IGlobeViewUtil m_globeViewUtil=null;
private IGlobeDisplay m_globeDisplay=null;
private ISceneViewer m_sceneViwer=null;
private int m_srcX;
private int m_srcY;
private bool m_bDrawPoint=false;

m_globeViewUtil=m_globeHookHelper.Camera as IGlobeViewUtil;

m_globeDisplay=m_globeHookHelper.GlobeDisplay;
m_sceneViwer=m_globeHookHelper.ActiveViewer;
//Start listening to globe display events.
((IGlobeDisplayEvents_Event)m_globeDisplay).AfterDraw += new
    IGlobeDisplayEvents_AfterDrawEventHandler(OnAfterDraw);

public override void OnMouseDown(int Button, int Shift, int X, int Y)
{
    m_srcX=X;
    m_srcY=Y;

    //Switch into tracking mode.
    m_bDrawPoint=true;

    //Refresh the display so that the AfterDraw gets called.
    m_sceneViwer.Redraw(false);
}

public override void OnMouseMove(int Button, int Shift, int X, int Y)
{
    //If not in tracking mode, just return.
    if (false == m_bDrawPoint)
        return ;

    //Cache the coordinates since they are needed for the AfterDraw.
    m_srcX=X;
    m_srcY=Y;

    //Refresh the display so that AfterDraw is called.
    m_sceneViwer.Redraw(false);
}

public override void OnMouseUp(int Button, int Shift, int X, int Y)
{
    //Switch off tracking mode.
    m_bDrawPoint=false;

    //Refresh the display so that AfterDraw is called.
    m_sceneViwer.Redraw(false);
}

Implementing OnAfterDraw event handler

1. Scroll down to the OnAfterDraw method. See the following code example:
   

public void OnAfterDraw(ISceneViewer pViewer){

}

double glX, glY, glZ;
m_globeViewUtil.WindowToGeocentric(m_globeDisplay, m_sceneViwer, m_srcX, m_srcY,
    true, out glX, out glY, out glZ);

//Draw the converted point on the surface of the globe.
GL.glPointSize(15.0f);
GL.glColor3ub(255, 0, 0);
GL.glBegin(GL.GL_POINTS);
GL.glVertex3f((float)glX, (float)glY, (float)glZ);
GL.glEnd();

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