On 12/8/06, Justin Heyes-Jones <[EMAIL PROTECTED]> wrote:
> I think it would be a good idea to add a fast pixel example to the examples.
>
> Something that demonstrates the different get and set pixel methods
> along with generate ones.
>
I agree. I offer my latest rotation function as a an example. I'm
not proud of the complexity so maybe others can offer suggestions to
make it smaller ;-)
(defun rotate-surface(surf degrees)
"rotates a surface 0, 90, 180, or 270 degrees"
(declare (type fixnum degrees)
(optimize (speed 3)(safety 0)))
;;(assert (member degrees '(0 90 180 270)))
(if (= 0 degrees)
;; in the case of 0 degrees, just return the surface
surf
;; else do rotation
(let* ((w (sdl:surf-w surf))
(h (sdl:surf-h surf))
(even (evenp (/ degrees 90)))
(new-w (if even h w))
(new-h (if even w h))
(new-surf (sdl:create-surface new-w new-h :surface surf))
(new-x (case degrees
(90 #'(lambda (x y)
(declare (ignore x)(type fixnum x y))
(+ (1- new-w) (- 0 y))))
(180 #'(lambda (x y)
(declare (ignore y)(type fixnum x y))
(+ (1- new-w) (- 0 x))))
(270 #'(lambda (x y)
(declare (ignore x)(type fixnum x y))
y))))
(new-y (case degrees
(90 #'(lambda (x y)
(declare (ignore y)(type fixnum x y))
x))
(180 #'(lambda (x y)
(declare (ignore x)(type fixnum x y))
(+ (1- new-h) (- 0 y))))
(270 #'(lambda (x y)
(declare (ignore y)(type fixnum x y))
(+ (1- new-h) (- 0 x)))))))
(sdl:with-possible-lock-and-update (:surface new-surf)
(sdl:with-possible-lock-and-update (:surface surf)
(let ((read-pix (sdl:generate-read-pixel surf))
(write-pix(sdl:generate-write-pixel new-surf)))
(loop :for x :from 0 :to (1- w)
:do (loop :for y :from 0 :to (1- h)
:do (let ((pixel (funcall read-pix x y)))
(funcall write-pix
(funcall new-x x y)
(funcall new-y x y)
pixel)))))))
new-surf)))
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