Implementing Powerups - Developing Games With Ruby - page 175

Spawning Powerups On Map
Powerups are implemented, but not yet spawned. We will spawn 20 - 30 random powerups
when generating the map:
class Map
# ...
def initialize (object_pool)
# ...
generate_powerups
end
# ...
def generate_powerups
pups = 0
target_pups = rand ( 20. . 30 )
while pups < target_pups do
x = rand ( 0. . MAP_WIDTH * TILE_SIZE )
y = rand ( 0. . MAP_HEIGHT * TILE_SIZE )
if tile_at(x, y) != @water
random_powerup . new( @object_pool , x, y)
pups += 1
end
end
end
def random_powerup
[ HealthPowerup ,
RepairPowerup ,
FireRatePowerup ,
TankSpeedPowerup ]. sample
end
# ...
end
The code is very similar to generating boxes. It's probably not the best way to distribute
powerups on map, but it will have to do for now.
Respawning Powerups After Pickup
When we pick up a powerup, we want it to reappear in same spot 30 seconds later. A
thought “we can start a new Thread with sleep and initialize the same powerup there”
sounds very bad, but I had it for a few seconds. Then PowerupRespawnQueue was
born.