Making The Prototype Playable - Developing Games With Ruby - page 151

@@respawn ||= StereoSample . new( 11

$window , Utils . media_path( 'respawn.wav' ))

12

13 end
14 end
15 end

Displaying Explosion Damage Trails

When something blows up, you expect it to leave a trail, right? In our case explosions
disappear as if nothing has ever happened, and we just can't leave it like this. Let's
introduce Damage game object that will be responsible for displaying explosion residue
on sand and grass:
09-polishing/entities/damage.rb

1 class Damage < GameObject
2 MAX_INSTANCES = 100

attr_accessor :x , :y

3

@@instances = [] 4

5
6 def initialize (object_pool, x, y)
7 super (object_pool)
8 DamageGraphics . new( self )
9 @x , @y = x, y
10 track( self )
11 end
12
13 def effect?
14 true
15 end
16
17 private

18
19 def track (instance)
20 if @@instances . size < MAX_INSTANCES
21 @@instances << instance
22 else
23 out = @@instances . shift
24 out . mark_for_removal
25 @@instances << instance
26 end
27 end
28 end