return dir + File.separator + terrainType + ".png";
return dir + "/" + terrainType + ".png";
    protected String generateRelativeFileName(int i) {	String dir;	if (layer == LAYER_BUILDING)	    dir = "buildings";	else	    dir = "terrain";	String num = generateFileNameNumber(i);	if (num == null) { 	    return dir + File.separator + terrainType + ".png";	} else {	    return dir + File.separator + terrainType + "_" +        generateFileNameNumber(i) + ".png";	}    }