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authorDavid Thompson <dthompson2@worcester.edu>2013-07-18 08:00:19 -0400
committerDavid Thompson <dthompson2@worcester.edu>2013-07-18 08:00:19 -0400
commit617ee3d5c397dabf775f68a710ea0dfdc830a547 (patch)
tree1e0efee000aa6c6335ddd07214a474287da84094
parent7ba4471b8e4e602531e29ec4717501aef81f95d3 (diff)
Change animation-state type to be immutable.
-rw-r--r--2d/sprite.scm47
1 files changed, 27 insertions, 20 deletions
diff --git a/2d/sprite.scm b/2d/sprite.scm
index 5170a29..5719cd8 100644
--- a/2d/sprite.scm
+++ b/2d/sprite.scm
@@ -240,32 +240,38 @@ size."
(%make-animation-state animation frame-index frame-time playing)
animation-state?
(animation animation-state-animation)
- (frame-index animation-state-frame-index set-animation-state-frame-index!)
- (frame-time animation-state-frame-time set-animation-state-frame-time!)
- (playing animation-state-playing? set-animation-state-playing!))
+ (frame-index animation-state-frame-index)
+ (frame-time animation-state-frame-time)
+ (playing animation-state-playing?))
(define (make-animation-state animation)
(%make-animation-state animation 0 0 #t))
(define (update-animation-state state)
"Increments the frame time for the animation state and determines
-which frame to show."
+which frame to show. Returns a new animation-state object."
(let ((frame-time (1+ (animation-state-frame-time state)))
+ (frame-index (animation-state-frame-index state))
+ (playing (animation-state-playing? state))
(animation (animation-state-animation state)))
- (if (and (animation-state-playing? state)
- (= frame-time (animation-duration animation)))
- ;; Move to the next frame. If we exceeed the length of the
- ;; animation then start back at 0.
- (let ((frame-index (modulo (1+ (animation-state-frame-index state))
- (animation-length animation))))
- (set-animation-state-frame-time! state 0)
- (set-animation-state-frame-index! state frame-index)
- ;; Stop the animation if we've played it once already and
- ;; the animation does not loop.
- (when (and (= frame-index 0)
- (not (animation-loop? animation)))
- (set-animation-state-playing! state #f)))
- (set-animation-state-frame-time! state frame-time))))
+
+ ;; Return the same state object if the animation is not playing.
+ (cond ((not playing)
+ state)
+ ;; Return a new state object with a reset frame-index and
+ ;; frame-time if we've reached the end of the animation.
+ ;; Stops playing the animation if the animation does not
+ ;; loop.
+ ((and playing (= frame-time (animation-duration animation)))
+ (let* ((frame-index (modulo (1+ frame-index)
+ (animation-length animation)))
+ (frame-time 0)
+ (playing (or (not (= frame-index 0))
+ (animation-loop? animation))))
+ (%make-animation-state animation frame-index frame-time playing)))
+ ;; Return a new state object with an incremented frame index.
+ (else
+ (%make-animation-state animation frame-index frame-time playing)))))
(define (animation-state-frame state)
(animation-frame (animation-state-animation state)
@@ -301,7 +307,7 @@ which frame to show."
(color sprite-color set-sprite-color!)
(anchor sprite-anchor set-sprite-anchor!)
(vertices sprite-vertices set-sprite-vertices!)
- (animation-state sprite-animation-state))
+ (animation-state sprite-animation-state set-sprite-animation-state!))
(define* (make-sprite drawable #:optional #:key (position #(0 0)) (scale #(1 1))
(rotation 0) (color #xffffffff) (anchor 'center))
@@ -419,7 +425,8 @@ sprite."
"Renders a sprite. A sprite batch will be used if one is currently
bound."
(when (animation? (sprite-drawable sprite))
- (update-animation-state (sprite-animation-state sprite)))
+ (let ((state (update-animation-state (sprite-animation-state sprite))))
+ (set-sprite-animation-state! sprite state)))
(if *sprite-batch*
(draw-sprite-batched sprite)