fixed editing of color overlay filter

jme3-effects/src/main/java/com/jme3/post/filters/ColorOverlayFilter.java

@@ -69,8 +69,6 @@ public class ColorOverlayFilter extends Filter {
 
     @Override
     protected Material getMaterial() {
-
-        material.setColor("Color", color);
         return material;
     }
 
@@ -88,11 +86,15 @@ public class ColorOverlayFilter extends Filter {
      */
     public void setColor(ColorRGBA color) {
         this.color = color;
+        if(material != null) {
+            material.setColor("Color", color);
+        }
     }
 
     @Override
     protected void initFilter(AssetManager manager, RenderManager renderManager, ViewPort vp, int w, int h) {
         material = new Material(manager, "Common/MatDefs/Post/Overlay.j3md");
+        material.setColor("Color", color);
     }
 
     @Override