changed ImageBasedHeightMap to use JmeSystem to get ImageRaster

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@10024 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/terrain/com/jme3/terrain/heightmap/ImageBasedHeightMap.java

@@ -32,6 +32,7 @@
 package com.jme3.terrain.heightmap;
 
 import com.jme3.math.ColorRGBA;
+import com.jme3.system.JmeSystem;
 import com.jme3.texture.Image;
 import com.jme3.texture.image.DefaultImageRaster;
 import com.jme3.texture.image.ImageRaster;
@@ -97,7 +98,7 @@ public class ImageBasedHeightMap extends AbstractHeightMap implements ImageHeigh
     }
     
     protected ImageRaster getImageRaster() {
-        return new DefaultImageRaster(colorImage, 0);
+        return JmeSystem.createImageRaster(colorImage, 0);
     }
     
     public boolean load(boolean flipX, boolean flipY) {