Creating Artificial Intelligence - Developing Games With Ruby - page 115

empty update , on_collision(with) and on_damage(amount) methods for it
to work:
08-ai/entities/components/ai_input.rb

1 class AiInput < Component
2 UPDATE_RATE = 200 # ms

3
4 def initialize (object_pool)
5 @object_pool = object_pool
6 super ( nil )
7 @last_update = Gosu . milliseconds
8 end
9
10 def control (obj)
11 self . object = obj
12 @vision = AiVision . new(obj, @object_pool ,
13 rand ( 700. . 1200 ))
14 @gun = AiGun . new(obj, @vision )
15 @motion = TankMotionFSM . new(obj, @vision , @gun )
16 end
17
18 def on_collision (with)
19 @motion . on_collision(with)
20 end
21
22 def on_damage (amount)
23 @motion . on_damage(amount)
24 end
25
26 def update
27 returnif object . health . dead?
28 @gun . adjust_angle
29 now = Gosu . milliseconds
30 returnif now - @last_update < UPDATE_RATE
31 @last_update = now
32 @vision . update
33 @gun . update
34 @motion . update
35 end
36 end

It adjust gun angle all the time, but does updates at UPDATE_RATE to save CPU power.
AI is usually one of the most CPU intensive things in games, so it's a common practice to
execute it less often. Refreshing enemy brains 5 per second is enough to make them deadly.