Question

[layer tileGIDAt:position]

If I give it a position outside the map, I get an Assertion Failure, which is just normal.

I need a way to know when a tile exists. Before running the above code so I don’t get a an Assertion Failure and also to do other things in case the tile does not exist. But how can I? Is there not a method in the CCTMXLayer class to check that?

Answer 1

To test if a tile exists, test if the tile GID is 0. Before that you can test if the position is on the tilemap as such:

if (position.x < layer.size.width && 
    position.y < layer.size.height &&
    position.x >= 0 && position.y >= 0)
{
    // position is within tilemap layer …

    if ([layer tileGIDAt:position] != 0)
    {
        // tile at position exists …
    }
}