GL Draw Line прямоугольник

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() ;
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