1 files changed, 21 insertions, 15 deletions
diff --git a/examples/framebuffer.scm b/examples/framebuffer.scm
index 894cbc3..50c65e8 100644
--- a/examples/framebuffer.scm
+++ b/examples/framebuffer.scm
@@ -31,30 +31,36 @@
 
 (load "common.scm")
 
-(define framebuffer
-  (make-framebuffer 320 240))
-
 (define inner-camera
   (2d-camera #:area (make-rect 0 0 320 240)))
 
 (define outer-camera
   (2d-camera #:area (make-rect 0 0 640 480)))
 
-(define inner-sprite
-  (load-sprite "images/p1_front.png"))
+(define-signal framebuffer
+  (on-start (make-framebuffer 320 240)))
+
+(define-signal outer-sprite
+  (signal-map-maybe (lambda (framebuffer)
+                      (make-sprite (framebuffer-texture framebuffer)
+                                   #:anchor 'bottom-left))
+                    framebuffer))
 
-(define outer-sprite
-  (make-sprite (framebuffer-texture framebuffer)
-               #:anchor 'bottom-left))
+(define-signal player-sprite
+  (on-start (load-sprite "images/p1_front.png")))
 
 (define-signal scene
-  (render-begin
-   (with-framebuffer framebuffer
-     (with-camera inner-camera
-       (move (vector2 160 120)
-             (render-sprite inner-sprite))))
-   (with-camera outer-camera
-     (scale 2 (render-sprite outer-sprite)))))
+  (signal-let ((framebuffer framebuffer)
+               (outer-sprite outer-sprite)
+               (inner-sprite player-sprite))
+    (if (and framebuffer outer-sprite inner-sprite)
+        (render-begin
+         (with-framebuffer framebuffer
+           (with-camera inner-camera
+             (move (vector2 160 120) (render-sprite inner-sprite))))
+         (with-camera outer-camera
+           (scale 2 (render-sprite outer-sprite))))
+        render-nothing)))
 
 (with-window (make-window #:title "Simple Sprite Demo")
   (run-game-loop scene))