Do an array with the four layers

[thomas-saigre]

At each time we do something over the four layers, we have four times the same lines of code, it can be factorised.
Example :

{
    case 0:
        tile1[coord.second][coord.first] = tile ;
        break ;
    case 1:
        tile2[coord.second][coord.first] = tile ;
        break ;
    case 2:
        tile3[coord.second][coord.first] = tile ;
        break ;
    case 3:
        tile4[coord.second][coord.first] = tile ;
        break ;
    default:
        std::cerr << "Wrong layer" << std::endl ;
}

should be replaced by tiles_layers[layer][coord.second][coord.first]