[imago-devel] IMAGO images <-> SDL surfaces

[matthieu.villeneuve at free.fr]

Hello,

Selon Vladimir Sedach <sedachv at cpsc.ucalgary.ca>:
> I've written a bit of code to shuffle between IMAGO images and SDL
> surfaces. It should be fast enough to do manipulations on small
> sprites in real-time on a reasonably fast machine.

Nice!

> (defun convert-to-image (surface)
>   "Given a 24 or 32-bit depth SDL surface, returns an IMAGO RGB image
> of the same width and height and RGB pixel contents."
>   (assert (or (= 24 (sdl:pixel-format-bits-per-pixel
>                      (sdl:surface-format surface)))
>               (= 32 (sdl:pixel-format-bits-per-pixel
>                      (sdl:surface-format surface)))))
>   (let* ((width (sdl:surface-w surface)) (height (sdl:surface-h surface))
>          (image (make-instance 'imago:rgb-image :width width :height height))
>          (image-array (imago:image-pixels image)))
>     ;; Note that on 32 bit machines, width and height are 32 bit ints
>     (declare (type fixnum width height)
>              (type (simple-array (unsigned-byte 32) (* *)) image-array))
>     (with-surface-lock surface
>       (dotimes (y height)
>         (declare (type fixnum y))
>         (dotimes (x width)
>           (declare (type fixnum x))
>           (setf (aref image-array y x) (sdl:get-pixel surface x y)))))
>     image))

A little note: using the IMAGO:DO-IMAGE-PIXELS macro could make the
code a little bit more abstract as well as more efficient. Here is
what the body of that function would look like:

(defun convert-to-image (surface)
  (let ((image (make-instance 'imago:rgb-image
                              :width (sdl:surface-w surface)
                              :height (sdl:surface-h surface))))
    (with-surface-lock surface
      (imago:do-image-pixels (image pixel x y)
        (setf pixel (sdl:get-pixel surface x y)))))
    image))


--
Matthieu Villeneuve