Relevant Game Info:
-Isometric-ish. i.e. If there are tiles the majority are empty since there isn't any tile backgrounds.

-Lots of units, lots of bullets, lots of players.

Problem:
I understand that dynamic allocations within the game loop are bad for performance, but the units are fairly dynamic (or should be when I am farther along).

Right now there is a stl::vector<> holding pointers to a base class of all units. Iteration is fairly nasty with large numbers of units.

Solution:
Have a large pool of memory for units preallocated. Copy new units over and use a bitvector to manage which slots are used and which slots are empty. Have secondary indexes on this list for optomized traversal.

Does this sound like it would work? Has anyone done anything similar? Am I wasting my energy and my time for a marginal performance boost?

[One might notice I never mentioned what performance I am getting and what performance I hope for... although it is important I would appreciate it if this aspect was ignored]

Thank you in advance.

------------------
Dark Lord Pi

I thank you for your response, but it didn't answer the other half of my question:
How do you store the units?

Is it in one massive array?
ex.
class Unit { blah... }
Unit[30000000] units;

Or seperately by type? Or what?

The problem I am having is that I think I should make secondary indexes on units stored by type, but I have no idea if this is necessary or logical.

ex.
class OnePlayer {
blah...
(Unit *)[5000] uOwned;
};

class UnitStore {
blah...
makeOnePlayersUnitsIterator(PlayerID);
makeTypeIterator(TypeID);
randomAccessUnit(UnitID);
makeSuperHoohahIterator(struct SuperHoohah);

private:
UnitType1[1000] ut1;
UnitType2[1000] ut2;
:
:
UnitTypek[1000] utk;
};

class OnePlayersUnitsIterator {
OnePlayersUnitsIterator(PlayerID) {
lookup OnePLayer,
traverse its uOwned array
}
blah...
};

class OneTypeIterator {
OneTypeIterator(TypeID) {
go to UnitStore,
traverse a type's array
}
blah...
};

And that way the various iterators could be optimized and would not have to search the entire list.

This raises the problem of allocating memory for the various types, though. Maybe no one wants to use type4, but everyone uses a lot of type7? Urg.

------------------
Dark Lord Pi