Multiplayer Creativity vs. AI
Exp:WW2 is not designed primarily as a single player game.
The reason for this is that single player games need a good
computer opponent and this requires good artificial intelligence (AI).
So far their have been not been any complex strategy games that
have provided players with a very challenging AI. Usually, the
excuse for poor AI performance has been that programmers haven't
been given the time to develop the AI. This is not, to my opinion,
the main reason for poor AI performance. I strongly believe that
human creativity is much more capable of providing a challenge than
AI. Humans can adapt and learn quickly from each other and will
therefore be less predictable.
Despite this, Expansion is not devoid of AI, since I also believe
in giving players the capability of not having to know about all
military, political or economic details.
Within the realm of Artificial Intelligence
(AI), there are different ways of translating
input (the situation on the battlefield, for instance)
into output (the strategy or tactic to be employed).
One such way is through the use of Fuzzy State Machines
(FuSM). Contrary to the Finite State Machine (FSM)
which needs specific input and produces specific
output, the FuSM is capable of producing different
output under the same circumstances. So, whereas
a FSM's response is always predictable, that of a FuSM
is merely plausible, so it could react flexibly to
changing situations. Expansion uses two FuSMs:
the Supreme Commander and the Battle Commander.
The Supreme Commander
Of the two AI components of Expansion, the
Supreme Commander is used to perform most of a
players's job. For a player interested in military
affairs, the Supreme Commander will not be
needed. This component is useful, however, as
either a computer opponent or to do (some of) the
work of a player not so much interested in
What the Supreme Commander does is to get a
general overview of the battle field and to
decide which battle commanders should attack,
defend, recruit, rest, or make any other
strategic decision. These decisions are based
upon an analysis of the world known to the
Supreme Commander, on the commander's character,
and on the options a player sets for determining
strategy. Basically, the Supreme Commander's job
seems simple: have Battle Commanders attack
where enemy resistance is likely to be small and
have them defend elsewhere.
But this takes quite a lot of analyzing. How do
we define our own strength and that of the enemy?
Where is resistance likely to be small? Is a
large army at the other side of the English
Channel a danger or not? These are some of the
questions the Supreme Commander needs to answer.
The Battle Commander
The other component of the AI within
Expansion, is called the Battle Commander. While
there is only one Supreme Commander, there will
most likely be several Battle Commanders. These
control the armies, fleets or air fleets and are
known as generals, admirals, or air marshalls,
but we will simply refer to them as commanders.
Just as with the Supreme Commander, Battle
Commanders are able to take over from humans.
Well, more or less, since I still hold the belief
that human creativity can never be replaced
by computer power. So I suggest planning most of
your campaigns yourself.
Whereas the Supreme Commander makes strategic
decisions, Battle Commanders make tactical
decisions. When giving orders, players can simply
choose any of the generic options (Commander
Decides, Attack, or Defend) to
activate a Battle Commander. If the Commander
Decides option has been chosen, the Battle
Commander will do the job of the Supreme
Commander, but on a smaller scale: just for his
own army. The result will be the decision to
attack or defend.
The other generic options, given to the Battle
Commander by either the player, the Supreme
Commander, or by himself when forced to by the Commander
Decides option, will make the Battle
Commander decide a more detailed tactic. For
example: a player gives orders to an army, but
chooses the option Commander Decides.
The Battle Commander will analyse his situation
and decides to choose the option to Defend.
The next step is that the commander has to choose
a more detailed defense tactic. The Defense
in Depth tactic is chosen by the Battle Commander.
How does a Battle Commander reach that
decision? The answer is still debatable. It
involves assessing the strength of nearby
friendly and enemy units and taking into account
the different unit types employed. With the means
at hand, the goal (given by the player or the
Supreme Commander) should be reached. If the odds
are against him, the Battle Commander will either
defend or retreat.
Expansion Games is dedicated to bringing games that
will eventually have a challenging AI. This will be achieved through
a gradual incorporation of :
- a neural net with continuous learning
- an even faster learning by analysis of moves made by succesful players
- a multi-level AI, by having different AI algoritms for the strategic and operational levels
- appointments of hotspots: analysis of a map where the AI goals are shown
- influence mapping: analysis of a map where the strength and weaknesses of friendly and enemy forces are seen
- a threaded AI: when the program waits until a player ends his turn, it will use that time to 'think'
- a historic database