I've created a tiled map that holds two layers, one for the tile type, and the other for whether it is solid or not. I plan on creating very big maps, and checking every tile seems like it would slow down my game immensely.
So lets say I had an array of integers. "0" representing solid, and "1" representing not solid. How would I check only the 8 surrounding integers instead of the whole array each update.
0 0 0
0 1 0
0 0 0