UNIX Version  (Windows Below)

/*#####################################*/ /*Description:   program to draw three red lines     */ /*   to a GLUT window  that is 500x500 pixels          */ /*Author:  L. Grewe                                                    */ /*Date: 1-1-99                                                            */ /*#####################################*/   #include <GL/gl.h> #include <GL/glut.h> #include <stdlib.h> #include <stdio.h> #include <math.h> /*Function prototypes*/ GLvoid display(GLvoid); GLvoid myinit(GLvoid);          void main(int argc, char **argv)        {                    glutInit(&argc,argv); /*init.  GLUT window sys.*/            /*there will be a single buffered  window displaying RGB */           glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);             glutInitWindowSize(500,500);   /*size in pixels  */          glutInitWindowPosition(0,0);   /* located lower-left of screen */           /*Create the window using the setup from the previous glut calls*/            glutCreateWindow("Lines Example");  /*title=Lines Example*/            /*tell system what function will be in charge of displaying*/            glutDisplayFunc(display);              /*Call another function to further initialize window contents*/            myinit();            /*this call causes to go in infinite loop waiting for window i/o */            glutMainLoop();        }                                         /*#####################################*/        /*myinit:  this function clears the background of the */        /*  graphics system and sets up the drawing color to */        /*  red.  Finally, viewing parameters are set.             */        /*#####################################*/        GLvoid myinit(GLvoid)        {             /*white background  */           glClearColor(1.0,1.0,1.0,0.0);            /*drawing color red  */          glColor3f(1.0,0.0,0.0);            /*Viewing Configuration  */          glMatrixMode(GL_PROJECTION);  /*says will specify project.  */          glLoadIdentity();   /*load identity matrix.*/            gluOrtho2D(0.0,500.0, 0.0, 500.0);  /*specifies Othographic proj*/                   /*Shift to Model Specification Model  */         glMatrixMode(GL_MODELVIEW);        }              /*#####################################*/        /*display:  this function draws three lines to the screen*/        /*#####################################*/        GLvoid display(GLvoid)        {             glClear(GL_COLOR_BUFFER_BIT); /*clear screen*/           glBegin(GL_LINES);                glVertex2f(100.0, 100.0); /*Line 1*/                glVertex2f(400.0, 400.0);                glVertex2f(100.0, 400.0); /*Line2 */              glVertex2f(400.0, 100.0);                glVertex2f(100.0, 250.0); /*Line 3*/                glVertex2f(400.0, 250.0);              glEnd();                       glFlush();  /*not needed but asks to draw ASAP.*/        }

 
 
 

Windows Version

/*#####################################*/ /*Description:   program to draw three red lines     */ /*   to a GLUT window  that is 500x500 pixels          */ /*Author:  L. Grewe                                                    */ /*Date: 1-1-99                                                            */ /*#####################################*/   #include <windows.h> #include <GL\Gl.h> #include <GL\glut.h> #include <stdlib.h>   #include <stdio.h> #include <math.h>     /*Function prototypes*/ GLvoid display(GLvoid); GLvoid myinit(GLvoid);          void main(int argc, char **argv)        {                    glutInit(&argc,argv); /*init.  GLUT window sys.*/            /*there will be a single buffered  window displaying RGB */           glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);             glutInitWindowSize(500,500);   /*size in pixels  */          glutInitWindowPosition(0,0);   /* located lower-left of screen */           /*Create the window using the setup from the previous glut calls*/            glutCreateWindow("Lines Example");  /*title=Lines Example*/            /*tell system what function will be in charge of displaying*/            glutDisplayFunc(display);              /*Call another function to further initialize window contents*/            myinit();            /*this call causes to go in infinite loop waiting for window i/o */            glutMainLoop();        }                                         /*#####################################*/        /*myinit:  this function clears the background of the */        /*  graphics system and sets up the drawing color to */        /*  red.  Finally, viewing parameters are set.             */        /*#####################################*/        GLvoid myinit(GLvoid)        {             /*white background  */           glClearColor(1.0,1.0,1.0,0.0);            /*drawing color red  */          glColor3f(1.0,0.0,0.0);            /*Viewing Configuration  */          glMatrixMode(GL_PROJECTION);  /*says will specify project.  */          glLoadIdentity();   /*load identity matrix.*/            gluOrtho2D(0.0,500.0, 0.0, 500.0);  /*specifies Othographic proj*/                   /*Shift to Model Specification Model  */         glMatrixMode(GL_MODELVIEW);        }              /*#####################################*/        /*display:  this function draws three lines to the screen*/        /*#####################################*/        GLvoid display(GLvoid)        {             glClear(GL_COLOR_BUFFER_BIT); /*clear screen*/           glBegin(GL_LINES);                glVertex2f(100.0, 100.0); /*Line 1*/                glVertex2f(400.0, 400.0);                glVertex2f(100.0, 400.0); /*Line2 */              glVertex2f(400.0, 100.0);                glVertex2f(100.0, 250.0); /*Line 3*/                glVertex2f(400.0, 250.0);              glEnd();                       glFlush();  /*not needed but asks to draw ASAP.*/        }