node-2d: Reimplement refresh-matrics to avoid use of is-a?

1 files changed, 21 insertions, 15 deletions

diff --git a/starling/node-2d.scm b/starling/node-2d.scm
index f6fc190..005d7f1 100644
--- a/starling/node-2d.scm
+++ b/starling/node-2d.scm
@@ -369,22 +369,28 @@
   (set! (dirty-matrix? node) #t)
   (set! (dirty-bounding-box? node) #t))
 
+(define-method (refresh-local-matrix (node <node-2d>))
+  (matrix4-2d-transform! (local-matrix node)
+                         #:origin (origin node)
+                         #:position (render-position node)
+                         #:rotation (rotation node)
+                         #:scale (scale node)
+                         #:skew (skew node)))
+
+(define-method (refresh-world-matrix (node <node-2d>) (parent <node-2d>))
+  (matrix4-mult! (world-matrix node) (local-matrix node) (world-matrix parent)))
+
+;; If a node has no parent or the parent is a 2D node, we simply copy
+;; the local matrix as the world matrix.
+(define-method (refresh-world-matrix (node <node-2d>) parent)
+  (let ((world (world-matrix node)))
+    (matrix4-identity! world)
+    (matrix4-mult! world world (local-matrix node))))
+
 (define-method (refresh-matrices (node <node-2d>))
-  (let ((local (local-matrix node))
-        (world (world-matrix node)))
-    (matrix4-2d-transform! local
-                           #:origin (origin node)
-                           #:position (render-position node)
-                           #:rotation (rotation node)
-                           #:scale (scale node)
-                           #:skew (skew node))
-    ;; Compute world matrix by multiplying by the parent node's
-    ;; matrix, if there is a 2D parent node, that is.
-    (if (and (parent node) (is-a? (parent node) <node-2d>))
-        (matrix4-mult! world local (world-matrix (parent node)))
-        (begin
-          (matrix4-identity! world)
-          (matrix4-mult! world world local)))))
+  (refresh-local-matrix node)
+  (refresh-world-matrix node (parent node)))
+
 
 (define-method (on-child-resize (node <node-2d>) child)
   #t)