OpenGL One Window 6 Views With Tao and C# (Multiple Views)

• Download demo - 199.82 KB
• Download source - 357.11 KB

Introduction

This project is based on my previous project "OpenGL 3D Navigation2 With Tao and CSharp".
It shows how to create multiple views on a single window. I did create 6 different views of the same object (cube). It also has an example of Glut fonts and glRasterPos3f() function.

Background

The goal of this program is to use multiple views in a single window. Therefore I'm going to explain a little bit about this subject. I also displayed fonts for each view. So I'm going to explain how I displayed the fonts. I'm not going to explain anything about how to navigate in 3D space because it is not the subject of this program.

This program (idea) is basically a copy of an existing idea - one window and multiple views. You can probably use multiple views in games with two or multiple players. Also you may use this in simulations where you want the simulation in a different perspective.

Dividing the window in multiple views is very simple. I will show how to do it below. The challenging part is to use this in your program.

Using Scissor

You start by enabling the SCISSOR_TEST.

Gl.glEnable(Gl.GL_SCISSOR_TEST);           // Enables SCISSOR

Second you set the ViewPort, window size and location:

Gl.glViewport(0, height, width, height);       // Set the viewPort
Gl.glScissor(0, height, width, height);        // Divide the window

Now you write your code for this window. I have the same code six times with different parameters, because I did divide the window in 6 views.

Gl.glMatrixMode(Gl.GL_PROJECTION);                          // Set the Matrix mode
Gl.glLoadIdentity();
Glu.gluPerspective(75f, (float)width / (float)height, 0.10f, 500.0f);  // Set the
                               // perspective
Gl.glMatrixMode(Gl.GL_MODELVIEW);
Gl.glLoadIdentity();
Glu.gluLookAt(0.0, 0.0, 15.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);    // Look at the
                               // new window at
                               // this position
drawCube();                         // Draw the cube

Once you are done, make sure to disable the Scissor test.

Gl.glDisable(Gl.GL_SCISSOR_TEST);  

Using Font

You need a small method with a for loop to render a string (text). The for loop goes through the string end sets the Font type and size for each character. In this case, the font type is Times Roman and size 24.

// Used for the font that will be displayed
static void text(string c)
{
    for (int i = 0; i < c.Length; i++)
    {
        // Render bitmap character
        Glut.glutBitmapCharacter(Glut.GLUT_BITMAP_TIMES_ROMAN_24, c[i]);
    }
} 

Then you set the position for the string (text) that you want to display and call your method with the string that you want to display.

Gl.glRasterPos3f(-15, 19 , -15);    // Set the position for the string (text)
text("Front");                      // Display the text "Front" 

Using the Code

About the Demo

I did include the Tao.OpenGL.dll and Tao.freeGlut.dll in the Demo folder. Normally it should execute without any problem. However, I did not test the demo on a different Operating System or computers so I don't know if it will work on your machine. You might need Vista and .NET Framework 2.0.

About the Source

I used Visual Studio 2005 (.NET Framework 2.0) C# and Tao (Tao.OpenGL, Tao.freeGlut). If you have VS 2005 and .NET Framework 2.0, you should not have any problem running the program from Visual Studio. Once you run the program, you can use the keyboard and mouse to navigate in 3D space.

Help

I did include lines through the x, y and z axis so that it will be easier to visualize. The dotted part is the negative side. The intersection of (x,y,z) is (0,0,0).

Line Colors

• Green for x axis
• Red for y axis
• Blue for z axis

Keys For Rotation (glRotatef())

• x rotates on x axis
• X rotates to opposite direction
• y rotates on y axis
• Y rotates to opposite direction
• z rotates on z axis
• Z rotates to opposite direction
• b,B rotates (+/-)90 degrees on x axis
• n,N rotates (+/-)90 degrees on y axis
• m,M rotates (+/-)90 degrees on z axis

Keys for Translation (glTranslatef())

• left_key - translates to left (x axis)
• right_key - translates to right (x axis)
• up_key - translates up (y axis)
• down_key - translates down (y axis)
• page_up - translates on z axis (zoom in)
• page_down - translates on z axis (zoom out)

Other Keys

• o,O brings everything to starting position
• F1 removes/shows the lines
• F2 rotates/stops the cube in x,y,z direction

Mouse

• LeftMouseDown translates cube in x and y direction (up/down,left/right)
• Mouse wheel translates cube in +/- z direction (zoom in / zoom out)

Code

using System;
using System.Collections.Generic;
using System.Text;
using Tao.OpenGl;
using Tao.FreeGlut;

namespace OpenGLOneWindow6Views
{
    sealed partial class OpenGLOneWindow6Views
    {
        // Declared static (no need for object reference)
        static float X = 0.0f;        // Translate screen to x direction (left or right)
        static float Y = 0.0f;        // Translate screen to y direction (up or down)
        static float Z = 0.0f;        // Translate screen to z direction (zoom in or out)
        static float rotX = 0.0f;    // Rotate screen on x axis 
        static float rotY = 0.0f;    // Rotate screen on y axis
        static float rotZ = 0.0f;    // Rotate screen on z axis

        static float rotLx = 0.0f;   // Translate screen by using  
				// the glulookAt function (left or right)
        static float rotLy = 0.0f;   // Translate screen by using  
				// the glulookAt function (up or down)
        static float rotLz = 0.0f;   // Translate screen by using  
				// the glulookAt function (zoom in or out)

        static bool lines = true;       // Display x,y,z lines (coordinate lines)
        static bool rotation = false;   // Rotate if F2 is pressed   
        static int old_x, old_y;        // Used for mouse event
        static int mousePressed;        // Check which botton is pressed

        // Used for the font that will be displayed
        static void text(string c)
        {
            for (int i = 0; i < c.Length; i++)
            {
                // Render bitmap character
                Glut.glutBitmapCharacter(Glut.GLUT_BITMAP_TIMES_ROMAN_24, c[i]);
            }
        }

          // Draw the lines (x,y,z)
        static void draw()
        {
            int width = Glut.glutGet(Glut.GLUT_WINDOW_WIDTH);  	// Get the windows width
            int height = Glut.glutGet(Glut.GLUT_WINDOW_HEIGHT);	// Get the windows height
            width = (width + 1) / 3;                           	// 3 OpenGL windows side 
							// by side
            height = (height + 1) / 2;                         	// 2 OpenGl windows up 
							// and down

            Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT); // Clear Color 
							// and Depth Buffer
           
            Gl.glEnable(Gl.GL_SCISSOR_TEST);     // Enable Scissor Test for multiple view
           
            // First window (Front view)
            Gl.glViewport(0, height, width, height);                  // Set the viewPort
            Gl.glScissor(0, height, width, height);                   // Divide the window
            setWindow(width, height);
            Glu.gluLookAt(0.0f , 0.0f , 15.0f , 0.0f, 0.0f, 
		0.0f, 0.0f, 1.0f, 0.0f);  // Look at the new window at this position  
            drawCube();        // Draw the cube
            Gl.glRasterPos3f(-15, 19, -15);    // Set the position for the string (text)
            text("Front");  // Display the text "Front"
           
            // Second Window (Back View)
            Gl.glViewport(0, 0, width, height);
            Gl.glScissor(0, 0, width, height);
            setWindow(width, height);
            Glu.gluLookAt(0.0f, 0.0f , -15.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);
            drawCube();
            Gl.glRasterPos3f(15.0f , 19.0f , 15.0f);
            text("Back");       

            // Third window (Right View)
            Gl.glViewport(width, height, width, height);
            Gl.glScissor(width, height, width, height);
            setWindow(width, height);
            Glu.gluLookAt(15.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);
            drawCube();
            Gl.glRasterPos3f(-15.0f, 19.0f, 15.0f);
            text("Right");

            // Forth Window (Left View)
            Gl.glViewport(width, 0, width, height);
            Gl.glScissor(width, 0, width, height);
            setWindow(width, height);
            Glu.gluLookAt(-15.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);
            drawCube();
            Gl.glRasterPos3f(15.0f, 19.0f, -15.0f);
            text("Left");

            // Fifth window (Upside down view)
            Gl.glViewport(2 * width, height, width, height);
            Gl.glScissor(2 * width, height, width, height);
            setWindow(width, height);
            Glu.gluLookAt(0.0f , 15.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f);
            drawCube();
            Gl.glRasterPos3f(-15.0f, -15.0f, -19.0f);
            text("Up");

            // Sixth window bottom up view
            Gl.glViewport(2 * width, 0, width, height);
            Gl.glScissor(2 * width, 0, width, height);
            setWindow(width, height);
            Glu.gluLookAt(0.0f, -15.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f);
            drawCube();
            Gl.glRasterPos3f(15.0f, 15.0f, -19.0f);
            text("Bottom");
         
            Gl.glDisable(Gl.GL_SCISSOR_TEST);
            Glut.glutSwapBuffers();
        }

        static void setWindow(float width, float height)
        {
            Gl.glMatrixMode(Gl.GL_PROJECTION); 	// Set the Matrix mode
            Gl.glLoadIdentity();
            Glu.gluPerspective(75.0f, (float)width / 
		(float)height, 0.10f, 500.0f);   // Set the perspective
            Gl.glMatrixMode(Gl.GL_MODELVIEW);
            Gl.glLoadIdentity();
        }
        static void drawCube()
        {
            // Clear the Color Buffer and Depth Buffer
            Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT);
            Gl.glPushMatrix(); 	// It is important to push the Matrix 
				// before calling glRotatef and glTranslatef
            Gl.glRotatef(rotX, 1.0f, 0.0f, 0.0f);            // Rotate on x
            Gl.glRotatef(rotY, 0.0f, 1.0f, 0.0f);            // Rotate on y
            Gl.glRotatef(rotZ, 0.0f, 0.0f, 1.0f);            // Rotate on z

            if (rotation) // If F2 is pressed update x,y,z for rotation of the cube
            {
                rotX += 0.2f;
                rotY += 0.2f;
                rotZ += 0.2f;
            }

            Gl.glTranslatef(X, Y, Z);        	// Translates the screen left or right, 
					// up or down or zoom in zoom out

            if (lines)  // If F1 is pressed don't draw the lines
            {
                // Draw the positive side of the lines x,y,z
                Gl.glBegin(Gl.GL_LINES);
                Gl.glColor3f(0.0f, 1.0f, 0.0f);                // Green for x axis
                Gl.glVertex3f(0f, 0f, 0f);
                Gl.glVertex3f(10f, 0f, 0f);
                Gl.glColor3f(1.0f, 0.0f, 0.0f);                // Red for y axis
                Gl.glVertex3f(0f, 0f, 0f);
                Gl.glVertex3f(0f, 10f, 0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);                // Blue for z axis
                Gl.glVertex3f(0f, 0f, 0f);
                Gl.glVertex3f(0f, 0f, 10f);
                Gl.glEnd();

                // Dotted lines for the negative sides of x,y,z coordinates
                Gl.glEnable(Gl.GL_LINE_STIPPLE);	// Enable line stipple to use 
						// a dotted pattern for the lines
                Gl.glLineStipple(1, 0x0101);     // Dotted stipple pattern for the lines
                Gl.glBegin(Gl.GL_LINES);
                Gl.glColor3f(0.0f, 1.0f, 0.0f);                    // Green for x axis
                Gl.glVertex3f(-10f, 0f, 0f);
                Gl.glVertex3f(0f, 0f, 0f);
                Gl.glColor3f(1.0f, 0.0f, 0.0f);                    // Red for y axis
                Gl.glVertex3f(0f, 0f, 0f);
                Gl.glVertex3f(0f, -10f, 0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);                    // Blue for z axis
                Gl.glVertex3f(0f, 0f, 0f);
                Gl.glVertex3f(0f, 0f, -10f);
                Gl.glEnd();
                Gl.glDisable(Gl.GL_LINE_STIPPLE);             // Disable the line stipple
            }

                // Drawing 3D cube
                // Front side 
                Gl.glBegin(Gl.GL_POLYGON);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);             // Set color to blue
                Gl.glVertex3f(3.0f, 3.0f, 3.0f);
                Gl.glColor3f(1.0f, 0.0f, 0.0f);             // Set color to red
                Gl.glVertex3f(3.0f, -3.0f, 3.0f);
                Gl.glColor3f(0.0f,0.0f, 1.0f);           
                Gl.glVertex3f(-3.0f, -3.0f, 3.0f);
                Gl.glColor3f(1.0f, 0.0f, 0.0f);             
                Gl.glVertex3f(-3.0f, 3.0f, 3.0f);
                Gl.glEnd();

                // Back side
                Gl.glBegin(Gl.GL_POLYGON);
                Gl.glColor3f(0.5f, 0.0f, .0f);            
                Gl.glVertex3f(3.0f, 3.0f, -3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(3.0f, -3.0f, -3.0f);
                Gl.glColor3f(0.5f, 0.0f, 0.0f);
                Gl.glVertex3f(-3.0f, -3.0f, -3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(-3.0f, 3.0f, -3.0f);
                Gl.glEnd();

                // Right side
                Gl.glBegin(Gl.GL_POLYGON);
                Gl.glColor3f(0.0f, 1.0f, 0.0f);        
                Gl.glVertex3f(3.0f, 3.0f, 3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f); 
                Gl.glVertex3f(3.0f, 3.0f, -3.0f);
                Gl.glColor3f(0.0f, 1.0f, 0.0f);
                Gl.glVertex3f(3.0f, -3.0f, -3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(3.0f, -3.0f, 3.0f);
                Gl.glEnd();
                
                // Left Side
                Gl.glBegin(Gl.GL_POLYGON);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(-3.0f, 3.0f, 3.0f);
                Gl.glColor3f(0.0f, 1.0f, 0.0f);
                Gl.glVertex3f(-3.0f, -3.0f, 3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(-3.0f, -3.0f, -3.0f);
                Gl.glColor3f(0.0f, 1.0f, 0.0f);
                Gl.glVertex3f(-3.0f, 3.0f, -3.0f);
                Gl.glEnd();
                
                // Upside
                Gl.glBegin(Gl.GL_POLYGON);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(3.0f, 3.0f, 3.0f);
                Gl.glColor3f(1.0f, 1.0f, 0.0f);
                Gl.glVertex3f(3.0f, 3.0f, -3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(-3.0f, 3.0f, -3.0f);
                Gl.glColor3f(1.0f, 1.0f, 0.0f);
                Gl.glVertex3f(-3.0f, 3.0f, 3.0f);
                Gl.glEnd();

                // Bottom
                Gl.glBegin(Gl.GL_POLYGON);
                Gl.glColor3f(1.0f, 1.0f, 0.0f);
                Gl.glVertex3f(3.0f, -3.0f, 3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(3.0f, -3.0f, -3.0f);
                Gl.glColor3f(1.0f, 1.0f, 0.0f);
                Gl.glVertex3f(-3.0f, -3.0f, -3.0f);
                Gl.glColor3f(0.0f, 0.0f, 1.0f);
                Gl.glVertex3f(-3.0f, -3.0f, 3.0f);
                Gl.glEnd();
                Gl.glColor3f(1.0f, 0.5f, 0.5f);    
           
                Glut.glutPostRedisplay();   	// Redraw the scene
                Gl.glPopMatrix();            	// Don't forget to pop the Matrix
        }
// This function is used for the navigation keys
        public static void keyboard(byte key, int x, int y)
        {
            switch (key)
            {
                // x,X,y,Y,z,Z uses the glRotatef() function
                case 120:    // x           	// Rotates screen on x axis 
                    rotX -= 2.0f;
                    break;
                case 88:    // X            	// Opposite way 
                    rotX += 2.0f;
                    break;
                case 121:    // y            	// Rotates screen on y axis
                    rotY -= 2.0f;
                    break;
                case 89:    // Y           	// Opposite way
                    rotY += 2.0f;
                    break;
                case 122:    // z            	// Rotates screen on z axis
                    rotZ -= 2.0f;
                    break;
                case 90:    // Z            	// Opposite way
                    rotZ += 2.0f;
                    break;

                // j,J,k,K,l,L uses the gluLookAt function for navigation
                case 106:   // j
                    rotLx -= 2.0f;
                    Gl.glMatrixMode(Gl.GL_MODELVIEW);
                    Gl.glLoadIdentity();
                    Glu.gluLookAt(rotLx, rotLy, 15.0 + rotLz, 
				0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
                    break;
                case 74:    // J
                    rotLx += 2.0f;
                    Gl.glMatrixMode(Gl.GL_MODELVIEW);
                    Gl.glLoadIdentity();
                    Glu.gluLookAt(rotLx, rotLy, 15.0 + rotLz, 0.0, 
				0.0, 0.0, 0.0, 1.0, 0.0);
                    break;
                case 107:   // k
                    rotLy -= 2.0f;
                    Gl.glMatrixMode(Gl.GL_MODELVIEW);
                    Gl.glLoadIdentity();
                    Glu.gluLookAt(rotLx, rotLy, 15.0 + rotLz, 0.0, 
				0.0, 0.0, 0.0, 1.0, 0.0);
                    break;
                case 75:    // K
                    rotLy += 2.0f;
                    Gl.glMatrixMode(Gl.GL_MODELVIEW);
                    Gl.glLoadIdentity();
                    Glu.gluLookAt(rotLx, rotLy, 15.0 + rotLz, 0.0, 
				0.0, 0.0, 0.0, 1.0, 0.0);
                    break;
                case 108: 	// (l) It has a special case when the rotLZ becames less 
			// than -15 the screen is viewed from the opposite side
                    	// therefore this if statement below does not allow 
			// rotLz be less than -15
                    if (rotLz + 14 >= 0)
                        rotLz -= 2.0f;
                    Gl.glMatrixMode(Gl.GL_MODELVIEW);
                    Gl.glLoadIdentity();
                    Glu.gluLookAt(rotLx, rotLy, 15.0 + rotLz, 0.0, 
				0.0, 0.0, 0.0, 1.0, 0.0);
                    break;
                case 76:    // L
                    rotLz += 2.0f;
                    Gl.glMatrixMode(Gl.GL_MODELVIEW);
                    Gl.glLoadIdentity();
                    Glu.gluLookAt(rotLx, rotLy, 15.0 + rotLz, 
				0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
                    break;
                case 98:    // b        // Rotates on x axis by -90 degree
                    rotX -= 90.0f;
                    break;
                case 66:    // B        // Rotates on y axis by 90 degree
                    rotX += 90.0f;
                    break;
                case 110:    // n       // Rotates on y axis by -90 degree
                    rotY -= 90.0f;
                    break;
                case 78:    // N        // Rotates on y axis by 90 degree
                    rotY += 90.0f;
                    break;
                case 109:    // m       // Rotates on z axis by -90 degree
                    rotZ -= 90.0f;
                    break;
                case 77:    // M        // Rotates on z axis by 90 degree
                    rotZ += 90.0f;
                    break;
                case 111:    // o       // Resets all parameters
                case 80:    // O        // Displays the cube in the starting position
                    rotation = false;
                    X = Y = 0.0f;
                    Z = 0.0f;
                    rotX = 0.0f;
                    rotY = 0.0f;
                    rotZ = 0.0f;
                    rotLx = 0.0f;
                    rotLy = 0.0f;
                    rotLz = 0.0f;
                    Gl.glMatrixMode(Gl.GL_MODELVIEW);
                    Gl.glLoadIdentity();
                    Glu.gluLookAt(rotLx, rotLy, 15.0f + rotLz, 0.0f, 0.0f, 
				0.0f, 0.0f, 1.0f, 0.0f);
                    break;
            }
            Glut.glutPostRedisplay();    	// Redraw the scene
        }

        // Called on special key pressed
        private static void specialKey(int key, int x, int y)
        {
            // Check which key is pressed
            switch (key)
            {
                case Glut.GLUT_KEY_LEFT:    	// Rotate on x axis
                    X -= 2.0f;
                    break;
                case Glut.GLUT_KEY_RIGHT:    	// Rotate on x axis (opposite)
                    X += 2.0f;
                    break;
                case Glut.GLUT_KEY_UP:       	// Rotate on y axis 
                    Y += 2.0f;
                    break;
                case Glut.GLUT_KEY_DOWN:    	// Rotate on y axis (opposite)
                    Y -= 2.0f;
                    break;
                case Glut.GLUT_KEY_PAGE_UP:  	// Rotate on z axis
                    Z -= 2.0f;
                    break;
                case Glut.GLUT_KEY_PAGE_DOWN:	// Rotate on z axis (opposite)
                    Z += 2.0f;
                    break;
                case Glut.GLUT_KEY_F1:      	// Enable/Disable coordinate lines
                    lines = !lines;
                    break;
                case Glut.GLUT_KEY_F2:      	// Enable/Disable automatic rotation
                    rotation = !rotation;
                    break;
                default:
                    break;
            }
            Glut.glutPostRedisplay();        	// Redraw the scene
        }

        // Capture the mouse click event 
        static void processMouseActiveMotion(int button, int state, int x, int y)
        {
            mousePressed = button;          	// Capture which mouse button is down
            old_x = x;                      	// Capture the x value
            old_y = y;                      	// Capture the y value
        }

        // Translate the x,y windows coordinates to OpenGL coordinates
        static void processMouse(int x, int y)
        {
            if ((mousePressed == 0))    	// If left mouse button is pressed
            {
                X = (x - old_x) / 15;     	// I did divide by 15 to adjust for a 
					// nice translation 
                Y = -(y - old_y) / 15;
            }

            Glut.glutPostRedisplay();
        }

        // Get the mouse wheel direction
        static void processMouseWheel(int wheel, int direction, int x, int y)
        {
            Z += direction;  // Adjust the Z value 

            Glut.glutPostRedisplay();
        }
        // Initialize the OpenGL window
        static void init()
        {
            Gl.glShadeModel(Gl.GL_SMOOTH);      	// Set the shading model to smooth 
            Gl.glClearColor(0, 0, 0, 1.0f);     	// Clear the Color
            Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT);    // Clear the 
							// Color and Depth Buffer
            Gl.glClearDepth(1.0f);          	// Set the Depth buffer value (ranges[0,1])
            Gl.glEnable(Gl.GL_DEPTH_TEST);  	// Enable Depth test
            Gl.glDepthFunc(Gl.GL_LEQUAL);   	// If two objects on the same 
					// coordinate show the first drawn
            Gl.glHint(Gl.GL_PERSPECTIVE_CORRECTION_HINT, Gl.GL_NICEST);
            Gl.glDisable(Gl.GL_CULL_FACE);
        }

        // This function is called whenever the window size is changed
        static void reshape(int w, int h)
        {
            Gl.glClearColor(0, 0, 0, 0.0f);
            Gl.glViewport(0, 0, w, h);                // Set the viewport
            Gl.glMatrixMode(Gl.GL_PROJECTION);        // Set the Matrix mode
            Gl.glLoadIdentity();
            Glu.gluPerspective(75f, (float)w / (float)h, 0.10f, 500.0f);
            Gl.glMatrixMode(Gl.GL_MODELVIEW);
            Gl.glLoadIdentity();
            Glu.gluLookAt(rotLx, rotLy, 15.0f + rotLz, 
			0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);
        }  
        // Main Starts
        static void Main(string[] args)
        {
            Glut.glutInit();           			// Initialize glut
            Glut.glutInitDisplayMode(Glut.GLUT_DOUBLE | Glut.GLUT_RGB); // Setup display 
					// mode to double buffer and RGB color
            Glut.glutInitWindowSize(600, 600);		// Set the screen size
            Glut.glutCreateWindow("OpenGL Multiple View"); 	// Windows capture
            init();     // Call init()
            Glut.glutReshapeFunc(reshape);
            Glut.glutDisplayFunc(draw);
            Glut.glutKeyboardFunc(new Glut.KeyboardCallback(keyboard)); 	// Set windows 
								// key callback     
            Glut.glutSpecialFunc(new Glut.SpecialCallback(specialKey));  // Set windows 
							// to specialKey callback
            Glut.glutMouseFunc(new Glut.MouseCallback
		(processMouseActiveMotion));   // Set window's to Mouse callback
            Glut.glutMotionFunc(new Glut.MotionCallback
			(processMouse)); 	// Set window's to motion callback
            Glut.glutMouseWheelFunc(new Glut.MouseWheelCallback
			(processMouseWheel));// Set window's to mouse motion callback
          
            Glut.glutMainLoop();
        }
   }
}