ArcEngine+OpenGL之三创建一个OpenGL研究区

 OpenGL之三创建一个OpenGL研究区
效果如下：


1、在ArcEngine中的OpenGL与在windowform中研究的区别：
  在window form 中，你必须设置如下等参数：

  void initializeGL();
  void paintGL();
  void resizeGL( int width, int height );

 但是在GlobeControl中没有这一套，因为，本身就是给予OpenGL开发。所以，其一上来就直接开始进行画：

 2、添加第一个点到GlobeControl。
 (1)添加研究例子地图。
 (2)指定研究地图。
注意：OpenGL中是给予地心坐标，所以，我们需要把大地坐标转化为地心坐标。
 代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.GlobeCore;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.SystemUI;
using OpenGL;
using ESRI.ArcGIS.Analyst3D;

namespace CEnOpenGLEx
{
    public sealed partial class MainForm : Form
    {
        #region private class members
        private IGlobeControl m_globeControl = null;
        private IGlobeViewUtil m_globeViewUtil = null;
        private IGlobeGraphicsLayer m_globeGraphicsLayer = null;
        private IGlobeDisplay m_globeDisplay = null;
        private ISceneViewer m_sceneViewer = null;
        #endregion

        #region calss constructor
        public MainForm()
        {
            InitializeComponent();
        }
        #endregion

        /// <summary>
        /// Form Load event handler
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void MainForm_Load(object sender, EventArgs e)
        {
            m_globeControl = axGlobeControl1.Object as IGlobeControl;

            //cast the GlobeViewUtil from the GlobeCamera
            m_globeViewUtil = m_globeControl.GlobeCamera as IGlobeViewUtil;
            m_globeDisplay = axGlobeControl1.GlobeDisplay;
            //Start listening to globe display events.
            ((IGlobeDisplayEvents_Event)m_globeDisplay).AfterDraw += new
            IGlobeDisplayEvents_AfterDrawEventHandler(OnAfterDraw);

        }

        #region Main Menu event handlers
        private void menuOpenDoc_Click(object sender, EventArgs e)
        {
            //execute Open Document command
            ICommand command = new ControlsGlobeOpenDocCommandClass();
            command.OnCreate(m_globeControl.Object);
            command.OnClick();
        }

        private void menuExitApp_Click(object sender, EventArgs e)
        {
            //exit the application
            Application.Exit();
        }
        #endregion

        /// <summary>
        /// Mouse move event handler
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void axGlobeControl1_OnMouseMove(object sender, IGlobeControlEvents_OnMouseMoveEvent e)
        {
            double dLon, dLat, dAlt;
            //convert the window coordinate into geographic coordinates
            m_globeViewUtil.WindowToGeographic(m_globeControl.GlobeDisplay,
                                               m_globeControl.GlobeDisplay.ActiveViewer,
                                               e.x,
                                               e.y,
                                               true,
                                               out dLon,
                                               out dLat,
                                               out dAlt);

            //report the mouse geographic coordinate onto the statusbar
            statusBarXY.Text = string.Format("{0} {1} {2}", dLon.ToString("###.###"), dLat.ToString("###.###"), dAlt.ToString("###.###"));
        }

        private void OnAfterDraw(ISceneViewer pViewer)
        {
            //指定画点x和y经纬度
            double m_srcX = 40.558;
            double m_srcY = 0.031;

            //Convert the mouse coordinate into a geocentric (OpenGL) coordinate system.
            double glX, glY, glZ;
            m_globeViewUtil.GeographicToGeocentric(m_srcX, m_srcY, 20, out glX, out glY, out glZ);


            //Draw the converted point on the surface of the globe.
            GL.glPointSize(50.0f);
            GL.glColor3ub(255, 0, 0);
            GL.glBegin(GL.GL_POINTS);
            GL.glVertex3f((float)glX, (float)glY, (float)glZ);
            GL.glEnd();
        }
    }
}