rip-bw-animated.scm

(use-syntax (ice-9 syncase))
(use-modules (ice-9 format))

(define filename "pokegra-w.narc")
(define outdir "scmtest")

(define ENOENT 2)
(define EEXIST 17)

(define (mkdir-if-not-exist dir)
  (catch 'system-error
         (lambda () (mkdir dir) #t)
         (lambda (key subr msg args rest)
           (define code (car rest))
           (if (eq? code EEXIST)
               #f
               (throw key subr msg args rest)))))

(mkdir-if-not-exist outdir)

(define (save-animation filename size nclr period callback)
  (save-gif filename size nclr 10
            (lambda (frame)
              (let ((tick (floor (* frame 6/10))))
                (if (< tick period)
                    (callback tick)
                    #f)))))

(let* ((n 525)
       (base (* n 20))
       (narc (load-narc filename))
       (nclr (narc-load-file narc (+ base 19) 'NCLR)) ; shiny
       (ncgr (narc-load-file narc (+ base 2) 'NCGR))
       (ncer (narc-load-file narc (+ base 4) 'NCER))
       (nanr (narc-load-file narc (+ base 5) 'NANR))
       (nmcr (narc-load-file narc (+ base 6) 'NMCR))
       (nmar (narc-load-file narc (+ base 7) 'NMAR))
       (cell 0)
       (period (nmar-period nmar cell))
       (size '(192 128)))
  (save-animation (format #f "~a/~a-anim.gif" outdir n)
                  size nclr period
                  (lambda (tick)
                    (let ((image (make-image size)))
                      (nmar-draw nmar cell tick
                                 nmcr nanr ncer ncgr
                                 image '(96 112))
                      image))))