gistfile1.java

Element groundLayer = getLayer(mapDocument, "ground");
int groundOffset = getFirstGID(mapDocument, "ground");
int[] groundGIDs = getGIDs(groundLayer);
for (int i = 0; i < groundGIDs.length; i++) {
    int id = groundGIDs[i];
    if (id > 0) {
        map.setTile(i % mapWidth, i / mapWidth,
                    (Image) tiles.get(id - groundOffset));
    }
}
Element powerupLayer = getLayer(mapDocument, "powerups");
int powerupOffset = getFirstGID(mapDocument, "powerups");
int[] powerupGIDs = getGIDs(powerupLayer);
for (int i = 0; i < powerupGIDs.length; i++) {
    int id = powerupGIDs[i];
    if (id > 0) {
        addSprite(map, powerups[id - powerupOffset],
                  i % mapWidth, i / mapWidth);
    }
}
Element mobLayer = getLayer(mapDocument, "mobs");
int mobOffset = getFirstGID(mapDocument, "mobs");
int[] mobGIDs = getGIDs(mobLayer);
for (int i = 0; i < mobGIDs.length; i++) {
    int id = mobGIDs[i];
    if (id > 0) {
        addSprite(map, mobs[id - mobOffset],
                  i % mapWidth, i / mapWidth);
    }
}