diff --git a/jme3-core/src/main/java/com/jme3/collision/DummyCollisionResults.java b/jme3-core/src/main/java/com/jme3/collision/DummyCollisionResults.java
new file mode 100644
index 000000000..f0f1777bd
--- /dev/null
+++ b/jme3-core/src/main/java/com/jme3/collision/DummyCollisionResults.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2009-2014 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.jme3.collision;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * DummyCollisionResults
is an empty "dummy" collection returned as a result of a
+ * collision detection operation done by {@link Collidable}.
+ * Its purpose is to avoid allocation of CollisionResults and its content,
+ * when collisionResults are out of our interest.
+ * Using the same API Collidable.collideWith() instead of possibly some new countCollideWith() implementation
+ * is chosen to keep the collision detection code "DRY", @see Don't repeat yourself
+ *
+ * @author Bebul
+ */
+public class DummyCollisionResults extends CollisionResults {
+ // the singleton for DummyCollisionResults is sufficient
+ private static DummyCollisionResults instance = null;
+
+ // exists only to defeat instantiation
+ protected DummyCollisionResults() {}
+
+ // classic singleton instance
+ public static DummyCollisionResults getInstance() {
+ if ( instance == null ) {
+ instance = new DummyCollisionResults();
+ }
+ return instance;
+ }
+
+ // Dummy implementation of CollisionResults
+ // All methods can be dummy except for iterator
+ @Override public void clear(){}
+ // even dummy iterator should return valid iterator
+ @Override public Iterator iterator() {
+ List dumbCompiler = Collections.emptyList();
+ return dumbCompiler.iterator();
+ }
+ @Override public void addCollision(CollisionResult result){}
+ @Override public int size(){ return 0; }
+ @Override public CollisionResult getClosestCollision(){ return null; }
+ @Override public CollisionResult getFarthestCollision(){ return null; }
+ @Override public CollisionResult getCollision(int index){ return null; }
+ @Override public CollisionResult getCollisionDirect(int index){ return null; }
+}
diff --git a/jme3-core/src/main/java/com/jme3/scene/Node.java b/jme3-core/src/main/java/com/jme3/scene/Node.java
index b8d379315..330ebaf4c 100644
--- a/jme3-core/src/main/java/com/jme3/scene/Node.java
+++ b/jme3-core/src/main/java/com/jme3/scene/Node.java
@@ -34,6 +34,7 @@ package com.jme3.scene;
import com.jme3.bounding.BoundingVolume;
import com.jme3.collision.Collidable;
import com.jme3.collision.CollisionResults;
+import com.jme3.collision.DummyCollisionResults;
import com.jme3.export.JmeExporter;
import com.jme3.export.JmeImporter;
import com.jme3.export.Savable;
@@ -491,13 +492,17 @@ public class Node extends Spatial implements Savable {
int total = 0;
// optimization: try collideWith BoundingVolume to avoid possibly redundant tests on children
+ // number 4 in condition is somewhat arbitrary. When there is only one child, the boundingVolume test is redundant at all.
+ // The idea is when there are few children, it can be too expensive to test boundingVolume first.
if (children.size() > 4)
{
BoundingVolume bv = this.getWorldBound();
if (bv==null) return 0;
- CollisionResults bvColRes = new CollisionResults();
- if (bv.collideWith(other, bvColRes) == 0) return 0;
+ // use DummyCollisionResults to avoid allocation while making the call to any BoundingVolume.collideWith possible
+ // moreover, the DummyCollisionResults operations are empty, so faster
+ DummyCollisionResults dummyColRes = DummyCollisionResults.getInstance();
+ if (bv.collideWith(other, dummyColRes) == 0) return 0;
}
for (Spatial child : children.getArray()){
total += child.collideWith(other, results);