Game AI Pro 2

Chapter 15

Subgoal Graphs for Fast Optimal Pathfinding

Tansel Uras and Sven Koenig

15.1 Introduction

Paths for game agents are often found by representing the map that the agents move on as a graph and using a search algorithm, such as A*, to search this graph. Pathfinding in games needs to be fast, especially if many agents are moving on the map. To speed up path planning, maps can often be preprocessed before games are released or when they are loaded into memory. The data produced by preprocessing should use a small amount of memory, and preprocessing should be fast if it is performed at runtime.

In this chapter, we present subgoal graphs, which are constructed by preprocessing maps that are represented as grids. Subgoal graphs use a small ...