How to deal with the immutability of returned structs?

Question

I\'m writing a game that has a huge 2D array of \"cells\". A cell takes only 3 bytes. I also have a class called CellMap, which contains the 2D array as a private field, and pro

Answer 1

If your cell map is in fact "sparse", that is, if there are a lot of adjacent cells that have either no value or some default value, I would suggest that you do not create a cell object for these. Only create objects for cells that actually have some non-default state. (This might reduce the total number of cells by a significant amount, thereby taking pressure off the garbage collector.)

This approach would of course require you to find a new way to store your cell map. You would have to get away from storing your cells in an array (since they are not sparse), and embrace a different kind of data structure, probably a tree.

For example, you could subdivide your map into a number of uniform regions such that you can translate any cell coordinates into a corresponding region. (You could further subdivide each region into sub-regions according to the same idea.) You could then have a search tree per region where the cell coordinates act as key into the tree.

Such a scheme would allow you to only store the cells you need, while still offering fast access to any cell in your map. If no cell at some specified coordinates is found in the trees, it can be assumed that it's a default cell.