Keeping track of thousands of objects

The image above is a cross-section of the randomly-generated map in Worldcrafter.  You can see tunnels, dungeons (some with floors of lava, mwah ha ha!) a lake and a lava river running along the bottom.  Other purple specks are things like monster generators, tangleweed and maybe even a chest of treasure.  It's pretty big, and yet the program has to keep track of a lot of the map blocks since they need processing to check if they should do anything, e.g. if they are water or lava, then flood.

The way the software does this is to have 3 lists of game "objects":-

1) Objects that need processing every game tick, e.g. a zombie.
2) Objects that don't need processing straight away but every few seconds at least, e.g. water blocks.
3) Objects that don't need processing until the player can see them.

So the first group of objects get processed every game tick, since it wouldn't do to have a zombie just stand there while the player throws rocks at it's head (although that might be realistic).  One or two objects from the second list are processed every tick since updates aren't as urgent.  And of the third massive list, one to two objects are checked every game tick to see if they are in range.  If they are, they are moved to the second list.

Easy peasy!  Look out for the new Worldcrafter update towards the end of the week.