node: Add visible? flag.

1 files changed, 19 insertions, 5 deletions

diff --git a/starling/node.scm b/starling/node.scm
index 4ce46dd..51866d2 100644
--- a/starling/node.scm
+++ b/starling/node.scm
@@ -31,11 +31,14 @@
             agenda
             booted?
             active?
+            visible?
             on-boot
             on-enter
             on-exit
             activate
             deactivate
+            show
+            hide
             update
             update*
             render
@@ -63,7 +66,10 @@
   ;; Flips to #t upon first entering a scene.
   (booted? #:accessor booted? #:init-form #f)
   ;; Flips to #t when node is part of current scene.
-  (active? #:accessor active? #:init-form #f))
+  (active? #:accessor active? #:init-form #f)
+  ;; Determines whether or not the node and all of its children are
+  ;; rendered.
+  (visible? #:accessor visible? #:init-form #t #:init-keyword #:visible?))
 
 (define (for-each-child proc node)
   (for-each proc (children node)))
@@ -97,8 +103,9 @@ the next update represented as a ratio in the range [0, 1]."
   "Render NODE and all of its children, recursively.
 ALPHA is the distance between the previous update and the next update
 represented as a ratio in the range [0, 1]."
-  (render node alpha)
-  (for-each-child (lambda (child) (render* child alpha)) node))
+  (when (visible? node)
+    (render node alpha)
+    (for-each-child (lambda (child) (render* child alpha)) node)))
 
 (define-method (on-boot (node <node>))
   "Perform initialization tasks for NODE."
@@ -136,8 +143,15 @@ represented as a ratio in the range [0, 1]."
   (with-agenda (agenda node)
     (set! (active? node) #f)
     (on-exit node)
-    (for-each-child deactivate node)
-    (reset-agenda)))
+    (for-each-child deactivate node)))
+
+(define-method (show (node <node>))
+  "Mark NODE as visible."
+  (set! (visible? node) #t))
+
+(define-method (hide (node <node>))
+  "Mark NODE as invisible."
+  (set! (visible? node) #f))
 
 
 ;;;