protected TerrainPatch findTopPatch(TerrainPatch tp) {
        if (tp.getQuadrant() == 2)
            return getPatch(1);
        else if (tp.getQuadrant() == 4)
            return getPatch(3);
        else if (tp.getQuadrant() == 1) {
            // find the patch above and ask it for child 2.
            TerrainQuad quad = findTopQuad();
            if (quad != null)
                return quad.getPatch(2);
        } else if (tp.getQuadrant() == 3) {
            TerrainQuad quad = findTopQuad();
            if (quad != null)
                return quad.getPatch(4);
        }

        return null;
    }
lock or unlock the meshes of this terrain.
Locked meshes are uneditable but have better performance.
@param locked or unlocked
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainQuad.java