Fix explosions

src/asteroids.cr

@@ -99,7 +99,7 @@ class Asteroids < Game
       bullet.position = wrap(bullet.position)
     end
 
-    @bullets = @bullets.reject { |b| b.age >= 4.0 }
+    @bullets = @bullets.reject(&.dead?)
     @asteroids.each do |a|
       a.update(dt)
       a.position = wrap(a.position)

src/bullet.cr

@@ -3,8 +3,11 @@ require "./lx_game/sprite/age"
 class Bullet < Sprite
   include LxGame::SpriteAge
 
+  @lifespan = 4.0
+
   def update(dt)
-    super
+    update_age(dt)
+    return if dead?
     update_position(dt)
   end
 

src/explosion.cr

@@ -2,4 +2,9 @@ require "./lx_game/sprite/age"
 
 class Explosion < LxGame::Emitter
   include LxGame::SpriteAge
+
+  def update(dt)
+    update_age(dt)
+    super
+  end
 end

src/lx_game/emitter.cr

@@ -8,7 +8,7 @@ module LxGame
     property max_age : Float64 = 1.0
     property emit_freq : Float64 = 0.05
     property strength : Float64 = 50.0
-    @last_emitted : Float64 = 0.0
+    getter last_emitted : Float64 = 0.0
     property emit_angle : Float64 = 2 * Math::PI
     property size : Float64 = 0.0
 
@@ -41,7 +41,7 @@ module LxGame
       end
 
       @particles.each { |particle| particle.update(dt) }
-      @particles.reject! { |particle| particle.dead? }
+      @particles.reject!(&.dead?)
     end
 
     def draw(renderer : SDL::Renderer)

src/lx_game/particle.cr

@@ -1,19 +1,14 @@
 require "./sprite"
+require "./sprite/age"
 
 module LxGame
   class Particle < Sprite
-    property age : Float64 = 0.0
+    include SpriteAge
-    property lifespan : Float64 = 4.0
-    @dead : Bool = false
-
-    def dead?
-      @age >= @lifespan
-    end
 
     def update(dt : Float64)
+      update_age(dt)
       return if dead?
       update_position(dt)
-      @age += dt
     end
 
     def draw(renderer : SDL::Renderer)

src/lx_game/sprite/age.cr

@@ -1,8 +1,13 @@
 module LxGame
   module SpriteAge
+    property lifespan : Float64 = Float64::INFINITY
     property age : Float64 = 0.0
 
-    def update(dt : Float64)
+    def dead?
+      self.age >= self.lifespan
+    end
+
+    def update_age(dt : Float64)
       self.age += dt
     end
   end