Fixed always adding a new node to AABBTree when updating a node.

lib/trees/aabb_node.rb

@@ -1,7 +1,8 @@
 class IMICFPS
   class AABBTree
     class AABBNode
-      attr_accessor :bounding_box, :parent, :object, :a, :b
+      attr_accessor :bounding_box, :parent, :object
+      attr_reader :a, :b
       def initialize(parent:, object:, bounding_box:)
         @parent = parent
         @object = object
@@ -11,6 +12,16 @@ class IMICFPS
         @b = nil
       end
 
+      def a=(leaf)
+        @a = leaf
+        @a.parent = self
+      end
+
+      def b=(leaf)
+        @b = leaf
+        @b.parent = self
+      end
+
       def leaf?
         @object
       end

lib/trees/aabb_tree.rb

@@ -32,7 +32,6 @@ class IMICFPS
     def update(object, bounding_box)
       leaf = remove(object)
       leaf.bounding_box = bounding_box
-      @objects[object]  = leaf
       insert_leaf(leaf)
     end
 
@@ -50,7 +49,6 @@ class IMICFPS
     def remove(object)
       leaf  = @objects.delete(object)
       @root = @root.remove_subtree(leaf) if leaf
-      @root.parent = nil
 
       return leaf
     end