Game Development Reference
In-Depth Information
One of the most useful applications of positive feedback in games is that it can be
used to make players win quickly once a critical difference is created. As should
become clear from Figure 4.7, positive feedback works to amplify small differences:
The difference between the balances of two bank accounts with equal interest rates
but different initial deposits will only grow over time. This effect of positive feed-
back can be used to drive a game toward a conclusion after the critical difference
has been made. After all, nobody likes to keep playing for long once it has become
clear who will win the game.
positiVe Feedback on destructiVe mechanisms
Positive feedback does not always work to make a player win; it can also make a player
lose. For example, losing pieces in a game of chess weakens your position and increases
the chance that you will lose more pieces; this is the result of a positive feedback loop.
Positive feedback can be applied to a destructive mechanism (as is the case with losing
material in chess). in this case, it is sometimes called a
downward spiral.
it is important
to understand that positive feedback on a destructive mechanism is not the same as neg-
ative feedback—negative feedback tends to damp out effects and produce equilibrium.
You can also have negative feedback attached to a destructive mechanism. The shooter
game
Half-Life
starts spawning more health packs when a player is low on hit points.
LOnG-T erm invesTmenTs vs. shOrT-T erm Ga ins
If
StarCraft
were a race to collect as many minerals as possible without any other
considerations, would the best strategy be to build a new SCV unit every time
you've collected enough minerals? No, not exactly. If you keep spending all your
income on new SCVs, you would never save any minerals, which is what you need
to win the game. To collect minerals, at some point you need to stop producing
SCVs and start stockpiling. The best moment to do this depends on the goals and
the constraints of the game—and what the other players do. If the goal is to accu-
mulate the biggest pile of minerals in a limited amount of time or to accumulate a
specific number of minerals as quickly as possible, there is an ideal number of SCV
units you should produce.
To understand this effect, look at
Figure 4.8
. It shows that as long as you're invest-
ing in new SCVs, your minerals do not accumulate. However, as soon as you stop
investing, the minerals increase at a steady pace. This pace depends on the number
of SCV units you have. The more you have, the faster your minerals will increase.
The longer you keep investing, the later you will start accumulating minerals, but
you will eventually catch up and overtake anybody who started accumulating before
you did. Depending on the target goal, one of those lines is the most effective.
