i cant display anything from this code. why?

#include <GL/glut.h>

void init (void)
glClearColor (0.0, 0.0, 0.0, 0.0); //Set display-window color //or can use glClearIndex (index);
glMatrixMode (GL_PROJECTION);
gluOrtho2D (0.0, 200.0, 0.0, 150.0);

void lineSegment (void)

glColor3f (0.0, 1.0, 0.0);

glBegin(GL_QUADS);						// Draw A Quad

	glVertex3f(-1.0f, 1.0f, 0.0f);				// Top Left
	glVertex3f( 1.0f, 1.0f, 0.0f);				// Top Right
	glVertex3f( 1.0f,-1.0f, 0.0f);				// Bottom Right
	glVertex3f(-1.0f,-1.0f, 0.0f);				// Bottom Left

glEnd();							// Done Drawing The Quad

glFlush ();


void main (int argc, char** argv)
glutInit (&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition (50, 100);
glutInitWindowSize (400, 300);
glutCreateWindow (“An example OpenGL Program”);

init ();
glutDisplayFunc (lineSegment);
glutMainLoop ();


There’s nothing wrong with your code, per se, but you’re going to need a microscope to see that tiny green quad in the lower left corner of your screen :wink:

Try adjusting the parameters to gluOrtho2D, such that they’re more in line with the size of your quad. It would do just as well to make your quad larger.