;; this file:
;;   https://dataswamp.org/~incal/common-lisp/general-base/gb-2d.lisp

(defun gb-2d-demo ()
  (sdl2:with-init (:everything)
    (sdl2:with-window (win :title "General Base 2D demo"
                           :flags '(:shown :opengl))
      (sdl2:with-gl-context (gl-context win)
        (init-gl gl-context win)
        (let ((draw t)
              (plen 0) )
          (sdl2:with-event-loop (:method :poll)
            (:keydown (:keysym ks)
               (let ((scv  (sdl2:scancode-value ks))
                     (symv (sdl2:sym-value ks))
                     (modv (sdl2:mod-value ks)) )
                 (cond
                   ;; [P] draw
                   ((sdl2:scancode= scv :scancode-p)
                     (setf draw (not draw)))
                   ;; [Q] quit
                   ((sdl2:scancode= scv :scancode-q)
                     (sdl2:push-event :quit)) )
                 (format t "key: ~a ~a ~a~%" scv symv modv) ))
            (:idle ()
               (when draw
                 (gl:clear :color-buffer :depth-buffer)
                 (gl:flush)
                 (sdl2:gl-swap-window win)
                 (sdl2:delay plen) ))
            (:quit () t) ))))))