(import
 (owl toplevel)
 (raylib))

(lambda (_)
  (set-target-fps! 120)
  (with-window
   600 600 "mp"
   (let loop ((last (mouse-pos)) (persist ()) (sz 1))
     (let* ((delta-sum (+ (abs (car (mouse-delta))) (abs (cdr (mouse-delta)))))
            (mp (mouse-pos))
            (sz (/ (- 100 delta-sum) 10))
            (persist (if (mouse-btn-down? mouse-button-left)
                         (append persist (list (list sz last mp)))
                         persist)))
       (draw
        (clear-background black)
        (draw-line-ex last mp sz white)
        (for-each
         (lambda (p) (draw-line-ex (cadr p) (caddr p) (car p) white))
         persist)
        (draw-circle '(100 10) sz white)
        (draw-fps '(0 0)))
       (if (window-should-close?)
           0
           (loop mp persist sz))))))