Fixes matrix transformations in sprites

sky/examples/game/lib/sprite_box.dart

Index: sky/examples/game/lib/sprite_box.dart
diff --git a/sky/examples/game/lib/sprite_box.dart b/sky/examples/game/lib/sprite_box.dart
index 6e7b6868f401bdd48d09aeb99e904246ad3f3992..7c95ee79d9066d2f80aaf437f2211e518fe1f458 100644
--- a/sky/examples/game/lib/sprite_box.dart
+++ b/sky/examples/game/lib/sprite_box.dart
@@ -11,8 +11,10 @@ enum SpriteBoxTransformMode {
 
 class SpriteBox extends RenderBox {
 
+  // Member variables
+
   // Root node for drawing
-  TransformNode _rootNode;
+  Node _rootNode;
 
   // Tracking of frame rate and updates
   double _lastTimeStamp;
@@ -22,7 +24,9 @@ class SpriteBox extends RenderBox {
   double _systemWidth;
   double _systemHeight;
 
-  SpriteBox(TransformNode rootNode, [SpriteBoxTransformMode mode = SpriteBoxTransformMode.nativePoints, double width=1024.0, double height=1024.0]) {
+  // Setup
+
+  SpriteBox(Node rootNode, [SpriteBoxTransformMode mode = SpriteBoxTransformMode.nativePoints, double width=1024.0, double height=1024.0]) {
     assert(rootNode != null);
     assert(rootNode._spriteBox == null);
 
@@ -40,30 +44,31 @@ class SpriteBox extends RenderBox {
     _scheduleTick();
   }
 
-  void _addSpriteBoxReference(TransformNode node) {
+  void _addSpriteBoxReference(Node node) {
     node._spriteBox = this;
-    for (TransformNode child in node._children) {
+    for (Node child in node._children) {
       _addSpriteBoxReference(child);
     }
   }
 
+  // Properties
+
   double get systemWidth => _systemWidth;
   double get systemHeight => _systemHeight;
 
-  TransformNode get rootNode => _rootNode;
+  Node get rootNode => _rootNode;
 
   void performLayout() {
     size = constraints.constrain(Size.infinite);
   }
 
+  // Event handling
+
   void handleEvent(Event event, BoxHitTestEntry entry) {
-    switch (event.type) {
-      case 'pointerdown':
-        print("pointerdown");
-        break;
-    }
   }
 
+  // Rendering
+
   void paint(RenderObjectDisplayList canvas) {
     // Move to correct coordinate space before drawing
     double scaleX = 1.0;
@@ -104,7 +109,6 @@ class SpriteBox extends RenderBox {
         scaleX = size.width/_systemWidth;
         scaleY = scaleX;
         _systemHeight = size.height/scaleX;
-        print("systemHeight: $_systemHeight");
         break;
       case SpriteBoxTransformMode.fixedHeight:
         scaleY = size.height/_systemHeight;
@@ -129,6 +133,8 @@ class SpriteBox extends RenderBox {
     canvas.restore();
   }
 
+  // Updates
+
   int _animationId = 0;
 
   void _scheduleTick() {
@@ -151,4 +157,29 @@ class SpriteBox extends RenderBox {
     _rootNode.update(delta);
     _scheduleTick();
   }
+
+  // Hit tests
+
+  List<Node> findNodesAtPosition(Point position) {
+    assert(position != null);
+
+    List<Node> nodes = [];
+
+    // Traverse the render tree and find objects at the position
+    _addNodesAtPosition(_rootNode, position, nodes);
+
+    return nodes;
+  }
+
+  _addNodesAtPosition(Node node, Point position, List<Node> list) {
+    // Visit children first
+    for (Node child in node.children) {
+      _addNodesAtPosition(child, position, list);
+    }
+    // Do the hit test
+    Point posInNodeSpace = node.convertPointToNodeSpace(position);
+    if (node.hitTest(posInNodeSpace)) {
+      list.add(node);
+    }
+  }
 }