;;;;; Converted from the "Pattern" Processing example at:
;;;;; http://www.processing.org/learning/examples/pattern.html
;;;;; (C)2006 Luke J Crook
(in-package #:sdl-examples)
(defun stroke ()
(let ((prev-mouse-x 0) (prev-mouse-y 0))
(sdl:with-init ()
(sdl:window 200 200 :title-caption "Stroke, from Processing." :icon-caption "Stroke, from Processing.")
(setf (sdl:frame-rate) 60)
(sdl:clear-display (sdl:color :r 102 :g 102 :b 102))
(sdl:with-events ()
(:quit-event () t)
(:video-expose-event () (sdl:update-display))
(:idle () (sdl:update-display))
(:mouse-motion-event (:x x :y y)
(let ((speed (sdl-base::clamp (+ (abs (- x prev-mouse-x))
(abs (- y prev-mouse-y)))
0 255)))
(sdl:draw-filled-circle-* x y speed :color sdl:*white* :stroke-color sdl:*black*)
(setf prev-mouse-x x
prev-mouse-y y)))))))
