Checks if there is a tile at the given location (in tile coordinates) in the given layer. Returns
false if there is no tile or if the tile at that location has an index of -1.
Parameters
tileX: number
X position to get the tile from (given in tile units, not pixels).
tileY: number
Y position to get the tile from (given in tile units, not pixels).
Checks if there is a tile at the given location (in tile coordinates) in the given layer. Returns false if there is no tile or if the tile at that location has an index of -1.