Game Development Reference
FIG 7.26 An L-system tree.
Natural and familiar shapes can be created with L-systems (as shown in
Figure 7.26 ).
To produce a procedural map, at least two types of L-systems are
required: one for drawing the map layout with the transportation routes
and one for creating the buildings. Figure 7.27a illustrates a simple street
map using the same L-system as the one for the tree in Figure 7.26 with
the angle set to 90°. Figure 7.27b shows how an L-system can be used
to create buildings. Simple lines are replaced with 3D blocks. The result
in the three iterations shown hints at how compelling a fully finished
building could look.
On the Web
Procedural City Generator
The aforementioned techniques for generating a city procedurally
come from the research work of Muller and Parish. Their approach has
been packaged into the CityEngine software—a 3D modeling package
built purposely to generate vast city landscapes. A free trial can be
downloaded from http://procedural.com/ .