Tactics - Learning Game AI Programming with Lua - page 541

In theory, you can dramatically reduce the memory footprint of the influence map by only
allowing a single layer of grid cells to represent the entire navigation mesh as long as the
navigation mesh never overlaps itself. Better yet, you can modify the influence map to
contain only a collection of used cells ignoring height completely. These optimizations
would be excellent extensions that can support much larger navigation meshes and are left
to the user to extend.
A top-down overlay of an influence map construction
To create an influence map, simply pass in the navigation mesh to base the influence map
on as well as a configuration of how to create the map. Currently, only one influence map
is supported, as the sandbox contains a single instance of the influence map data structure.
Additional influence maps can be added to the sandbox C++ code and will require you to
create multiple instances and modify the Lua accessor functions to specify which influen-
ce map should be accessed:
Sandbox.CreateInfluenceMap(
sandbox, navMeshName, influenceMapConfig);