fixed NPE.

jme3-core/src/main/java/com/jme3/shadow/PointLightShadowRenderer.java

@@ -230,6 +230,11 @@ public class PointLightShadowRenderer extends AbstractShadowRenderer {
      */
     @Override
     protected boolean checkCulling(Camera viewCam) {
+
+        if (light == null) {
+            return false;
+        }
+
         Camera cam = viewCam;
         if(frustumCam != null){
             cam = frustumCam;