Game Development Reference
In-Depth Information
Closed Circuits Create Feedback
A feedback loop in a Machinations diagram is created by a closed circuit of con-
nections. Remember that feedback occurs when state changes create effects that
ultimately feed back to the original element. A closed circuit of connections will
cause this effect.
A closed circuit of only resource connections (as in Figure 6.16 ) cannot display very
complex behavior. The resource is pulled through the pools in circles creating a sim-
ple periodic system, but nothing more interesting can happen.
FIGURe 6.16
Feedback created by
only resource connec-
tions. The resource
simply goes round
and round.
The most interesting feedback loops consist of a closed circuit that mixes resource
connections and state connections. The loop should contain at least one label modi-
fier or activator. For example, the mechanism in Figure 6.17 uses an activator to
maintain the resources in the pool at about 20. It acts the way a heating system does
to keep a room warm in cold climates: It turns on a heater with a fixed output when
the temperature drops below 20. The graph in the same figure displays the tempera-
ture over time.
FIGURe 6.17
heater feedback
mechanism using
an activator
charts in machinations diaGrams
Using the online tool for machinations diagrams, it is very easy to produce charts track-
ing the number of resources in a pool over time. The chart in Figure 6.17 is produced by
the tool. You can add a chart to a diagram like any other element. To start measuring the
number of resources, simply connect a pool to the chart with a state connection. When
selected, this connection is displayed as normal, but when it is not selected, it is reduced
to two small arrows to avoid visual clutter.
 
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