Demonstration Program: Used to illustrate OpenGL primatives

  This is perhaps the simplest OpenGL program using the glut toolkit.
 

  Adapted from http://www.cs.uml.edu/~hmasterm/graphics.html
  by Jorge Lobo, May 2000.

\*********************************************************************/

#include <GL\glut.h>
#include <math.h>
 

void display( void );

void reshape( GLsizei w, GLsizei h );

//global

GLsizei wh = 500, ww = 500;                 //initial window size

//rehaping routine called whenever window is resized or moved

void reshape( GLsizei w, GLsizei h )
{
    glViewport( 0, 0, w, h );

}

// Display Function: what is actually drawn to the screen

void display(void)
{
    //clear the screen and z buffer
 glClearColor( 0.0, 0.0, 0.0, 0.0 );
    glClear(GL_COLOR_BUFFER_BIT);

 //set the color

 glColor3f(1.0, 1.0, 1.0);  //initially white

 //set up other line parameters - INITIALLY COMMENTED OUT

 //glLineWidth(3.0);
 //glLineStipple(1,0x1c47);
 //glEnable(GL_LINE_STIPPLE);

 //draw the primitive

 glBegin (GL_POINTS);
 glVertex2f(-0.5, -0.5);
 glVertex2f(0.5, -0.5);
 glVertex2f(0.5, 0.5);
 glVertex2f(-0.5,0.5);
 glEnd();
 

 //flush the buffer
 glFlush();
 
 

}

int main( int argc, char** argv )
{

    //Initialize the glut system

    glutInit( &argc,argv );

 //set up double buffered window with depth

    glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB  );
    glutInitWindowSize( ww, wh );
    glutCreateWindow( "Illustrations of OpenGL Primitives" );

    // set up the viewing projection; this code sets up an orthographic projection with a
    // view volume extending from -1.0 to 1.0 in x,y,z directions

 glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
 glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);
 glMatrixMode(GL_MODELVIEW);

    // register callbacks

 glutDisplayFunc( display );
    glutReshapeFunc( reshape );

 // start the event loop
 glutMainLoop();

    return(0);
}