(bind-func circle_line
(lambda (radius:double x:double y:double)
(let ((k 0.0))
(glLineWidth 3.0)
(glBegin GL_LINE_LOOP)
(dotimes (k 90.0)
(let ((angle:double (/ (* k 2.0 PI) 90.0)))
(glVertex2d (+ x (* (cos angle) radius)) (+ y (* (sin angle) radius)))))
(glEnd))))