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#include <GL/glut.h>
#include <stdlib.h>
 
 
void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT);   //flush gl
//  glColor3f(1.0, 0.0, 0.0);       //red
 
    //hexagon
    glBegin(GL_POLYGON);
            glColor3f(1.0, 0.0, 0.0);       //red
        glVertex2i(40,80);      //left
        glVertex2i(80,120);     //LT
            glColor3f(0.0, 1.0, 0.0);       //green
        glVertex2i(160,120);    //RT
        glVertex2i(200,80); //Right
            glColor3f(0.0, 0.0, 1.0);       //blue
        glVertex2i(160,40);     //RB
        glVertex2i(80,40);      //RL
    glEnd();
    
    
 
    glFlush();  //force immidiate display
}
 
int main(int argc,char *argv[])
{
    glutInit(&argc,argv);                   //prepare glut
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);       //set the display mode
    glutInitWindowSize (500, 500);          //the size of the program window
    glutInitWindowPosition (100, 100);      //initial position for the window
    glutCreateWindow ("points and lines");  //create window with a title
    
    glClearColor(255,255,255,0.0);          //background color
    glMatrixMode (GL_PROJECTION);           //2d envyronment
    gluOrtho2D (40.0, 200.0, 40.0, 120.0);  //matrix dimensions
    
    glutDisplayFunc(display);               //show thee actual program
    glutMainLoop();
    
    return EXIT_SUCCESS;                    //exit the program
}