public void setFlushQueues(boolean flushQueues) {
        this.flushQueues = flushQueues;
    }
Set this to false if you want to use several PssmRenderers to have
multiple shadows cast by multiple light sources. Make sure the last
PssmRenderer in the stack DOES flush the queues, but not the others

@param flushQueues true to flush the queues, false to avoid flushing them
jme3-core/src/main/java/com/jme3/shadow/PssmShadowRenderer.java