Creating and Moving Agents - Learning Game AI Programming with Lua - page 102

Pursuit
Creating a pursuing agent is very similar to seeking, except that we predict the target posi-
tion of another moving agent. Start by creating a new PursuingAgent Lua script and
implement the basic Agent_Cleanup, Agent_HandleEvent ,
Agent_Initialize , and Agent_Update functions:
Create Lua file as follows:
src/my_sandbox/script/PursuingAgent.lua
As a pursuing agent needs to have an enemy to pursue, we create a persistent Lua variable
enemy outside the scope of our Initialize and Update functions. During the initializ-
ation of the agent, we will request all agents that are currently within the sandbox and as-
sign the first agent to be our enemy.
A minor change we make to the pursuing agent compared to the seeking agent is to use an
agent's PredictFuturePosition function to calculate its future position. We pass in
the number of seconds we want to predict in order to create the pursuing agent's target posi-
tion.
We can even make our pursuing agents slower than their enemy while still being able to
catch up to a future predicted position when the enemy agent changes directions:
PursuingAgent.lua :
require "AgentUtilities";
local enemy;
function Agent_Cleanup(agent)
end
function Agent_HandleEvent(agent, event)
end
function Agent_Initialize(agent)
AgentUtilities_CreateAgentRepresentation(
agent, agent:GetHeight(), agent:GetRadius());