/**
 * Control the movement and the collision of the character
 * @param map The map which we want to check collision
 */
public void ManageMovement(Map map) {
    boolean collision = false;

    if(Keyboard.isKeyDown(Keyboard.KEY_LEFT)) {
        for(int i = 0; i < map.GetNumLayers(); i++) {
            if((LeftTile(map, i, 0) > 128) || (LeftTile(map, i, 1) > 128)) {
                collision = true;
            }
        }

        if(!collision) AddPos(-vel, 0.0f);
    }
    else if(Keyboard.isKeyDown(Keyboard.KEY_RIGHT)) {
        for(int i = 0; i < map.GetNumLayers(); i++) {
            if((RightTile(map, i, 0) > 128) || (RightTile(map, i, 1) > 128)) {
                collision = true;
            }
        }

        if(!collision) AddPos(vel, 0.0f);
    }

    collision = false;
    if(Keyboard.isKeyDown(Keyboard.KEY_UP)) {
        for(int i = 0; i < map.GetNumLayers(); i++) {
            if((UpTile(map, i, 0) > 128) || (UpTile(map, i, 1) > 128)) {
                collision = true;
            }
        }

        if(!collision) AddPos(0.0f, -vel);
    }
    else if(Keyboard.isKeyDown(Keyboard.KEY_DOWN)) {
        for(int i = 0; i < map.GetNumLayers(); i++) {
            if((DownTile(map, i, 0) > 128) || (DownTile(map, i, 1) > 128)) {
                collision = true;
            }
        }

        if(!collision) AddPos(0.0f, vel);
    }
}

/**
 * A method to get the upper tile next to the character
 * @param map The map which we want to check the tile
 * @param layer The layer of the map
 * @param corner 0 indicates the upper-left corner of the character. 1 indicates the upper-right corner of the character
 * @return The kind of tile next to the character in that direction
 */
public int UpTile(Map map, int layer, int corner) {
    int tile = 255;

    switch(corner) {
        case 0:
            tile = map.GetValue(layer, (int) (x/size), (int) ((y-1)/size));
            break;
        case 1:
            tile = map.GetValue(layer, (int) ((x+size-1)/size), (int) ((y-1)/size));
            break;
    }

    return tile;
}

public int LeftTile(Map map, int layer, int corner) {
    int tile = 255;

    switch(corner) {
        case 0:
            tile = map.GetValue(layer, (int) ((x-1)/size), (int) (y/size));
            break;
        case 1:
            tile = map.GetValue(layer, (int) ((x-1)/size), (int) ((y+size-1)/size));
            break;
    }

    return tile;
}

public int DownTile(Map map, int layer, int corner) {
    int tile = 255;

    switch(corner) {
        case 0:
            tile = map.GetValue(layer, (int) (x/size), (int) (y/size + 1));
            break;
        case 1:
            tile = map.GetValue(layer, (int) ((x+size-1)/size), (int) (y/size + 1));
            break;
    }

    return tile;
}

public int RightTile(Map map, int layer, int corner) {
    int tile = 255;

    switch(corner) {
        case 0:
            tile = map.GetValue(layer, (int) (x/size + 1), (int) (y/size));
            break;
        case 1:
            tile = map.GetValue(layer, (int) (x/size + 1), (int) ((y+size-1)/size));
            break;
    }

    return tile;
}