@Override
    protected void prepareTerrain() {
        if (!addedTerrains.isEmpty()) {
            for (TerrainQuad t : addedTerrains) {
                if (!terrains.contains(t)) {
                    terrains.add(t);
                }
            }
            addedTerrains.clear();
        }
        
        if (!removedTerrains.isEmpty()) {
            terrains.removeAll(removedTerrains);
            removedTerrains.clear();
        }
        
        for (TerrainQuad terrain : terrains.getArray()) {
            // cache the terrain's world transforms so they can be accessed on the separate thread safely
            terrain.cacheTerrainTransforms();
        }
    }
Add a terrain that will no longer have its LOD handled by this control.
It will be removed next update run. You should only call this from
the render thread.
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/MultiTerrainLodControl.java