node: Add visible? flag.

1 files changed, 21 insertions, 20 deletions

diff --git a/starling/node-2d.scm b/starling/node-2d.scm
index a0b2746..368e8a2 100644
--- a/starling/node-2d.scm
+++ b/starling/node-2d.scm
@@ -314,26 +314,27 @@
   (next-method))
 
 (define-method (render* (node <node-2d>) alpha)
-  ;; Compute the linearly interpolated rendering position, in the case
-  ;; that node has moved since the last update.
-  (let ((p (position node))
-        (lp (last-position node))
-        (rp (render-position node))
-        (beta (- 1.0 alpha)))
-    (unless (and (= (vec2-x lp) (vec2-x rp))
-                 (= (vec2-y lp) (vec2-y rp)))
-      (set-vec2-x! rp (+ (* (vec2-x p) alpha) (* (vec2-x lp) beta)))
-      (set-vec2-y! rp (+ (* (vec2-y p) alpha) (* (vec2-y lp) beta)))
-      (set! (dirty-matrix? node) #t)))
-  ;; Recompute dirty matrices.
-  (when (dirty-matrix? node)
-    (compute-matrices! node)
-    (set! (dirty-matrix? node) #f)
-    ;; If the parent is dirty, all the children need to be marked as
-    ;; dirty, too.
-    (for-each (lambda (node)
-                (set! (dirty-matrix? node) #t))
-              (children node)))
+  (when (visible? node)
+    ;; Compute the linearly interpolated rendering position, in the case
+    ;; that node has moved since the last update.
+    (let ((p (position node))
+          (lp (last-position node))
+          (rp (render-position node))
+          (beta (- 1.0 alpha)))
+      (unless (and (= (vec2-x lp) (vec2-x rp))
+                   (= (vec2-y lp) (vec2-y rp)))
+        (set-vec2-x! rp (+ (* (vec2-x p) alpha) (* (vec2-x lp) beta)))
+        (set-vec2-y! rp (+ (* (vec2-y p) alpha) (* (vec2-y lp) beta)))
+        (set! (dirty-matrix? node) #t)))
+    ;; Recompute dirty matrices.
+    (when (dirty-matrix? node)
+      (compute-matrices! node)
+      (set! (dirty-matrix? node) #f)
+      ;; If the parent is dirty, all the children need to be marked as
+      ;; dirty, too.
+      (for-each (lambda (node)
+                  (set! (dirty-matrix? node) #t))
+                (children node))))
   (next-method))
 
 (define-method (activate (node <node-2d>))