CODE EXAMPLE FOR CPP

gl draw line rectangle

glBegin(GL_LINE_LOOP) ;
    glVertex3f(0.0, 0.0, 0.0);
    glVertex3f(0.0, 0.5, 0.0);
    glVertex3f(0.5, 0.5, 0.0);
    glVertex3f(0.5, 0.0, 0.0);
glEnd() ;