Make sprites immutable.

* 2d/sprite.scm (<sprite>): Make immutable.
  (set-sprite-drawable!, set-sprite-position!, set-sprite-scale!)
  (set-sprite-rotation!, set-sprite-color!, set-sprite-anchor!): Delete.
  (set-sprite-drawable, set-sprite-position, set-sprite-scale)
  (set-sprite-rotation, set-sprite-color, set-sprite-anchor): New
  procedures.

* examples/coroutine.scm:

* examples/particles.scm: Use immutable sprite setters.

2 files changed, 15 insertions, 10 deletions

diff --git a/examples/coroutine.scm b/examples/coroutine.scm
index 7b4a1e6..741b357 100644
--- a/examples/coroutine.scm
+++ b/examples/coroutine.scm
@@ -15,10 +15,12 @@
 ;;; along with this program.  If not, see
 ;;; <http://www.gnu.org/licenses/>.
 
-(use-modules (2d agenda)
+(use-modules (srfi srfi-26)
+             (2d agenda)
              (2d coroutine)
              (2d game)
              (2d sprite)
+             (2d texture)
              (2d vector2)
              (2d window))
 
@@ -27,19 +29,23 @@
 (define window-width 640)
 (define window-height 480)
 
-(define sprite (load-sprite "images/p1_front.png"
-                            #:position (vector2 320 240)))
+(define texture (load-texture "images/p1_front.png"))
+
+(define sprite
+  (make-sprite texture
+               #:position (vector 320 240)))
+
+(define (random-vector2)
+  (vector2 (random window-width)
+           (random window-height)))
 
 ;; Simple script that moves the sprite to a random location every
 ;; second.
 (coroutine
  (while #t
-   (set-sprite-position!
-    sprite
-    (vector2 (random window-width)
-             (random window-height)))
+   (set! sprite (set-sprite-position sprite (random-vector2)))
    (wait 15)
-   (set-sprite-rotation! sprite (random 360))
+   (set! sprite (set-sprite-rotation sprite (random 360)))
    (wait 15)))
 
 (add-hook! draw-hook (lambda (dt alpha) (draw-sprite sprite)))
diff --git a/examples/particles.scm b/examples/particles.scm
index 4269b99..b60a537 100644
--- a/examples/particles.scm
+++ b/examples/particles.scm
@@ -65,8 +65,7 @@
   (for-each
    (lambda (p)
      (let* ((sprite (particle-sprite p)))
-       (set-sprite-position! sprite (particle-position p))
-       (draw-sprite sprite)))
+       (draw-sprite (set-sprite-position sprite (particle-position p)))))
    particles))
 
 (define (draw dt alpha)