refactoring the multiple particle system complex example to use inner…

… classes

Former-commit-id: 8eab6d0
Former-commit-id: 6f3875d11dd22432348791f0bbd05e0df9a0b2e7

samples/processing_app/topics/simulate/multiple_particle_systems.rb

@@ -5,10 +5,51 @@
 # Each burst is one instance of a particle system with Particles and
 # CrazyParticles (a subclass of Particle).
 
+module Runnable
+  def run
+    self.reject! { |item| item.dead? }
+    self.each    { |item| item.run   }
+  end
+end
+
+
+class Vector
+  attr_accessor :x, :y
+
+  def initialize(x, y)
+    @x, @y = x, y
+  end
 
-require 'ruby-processing'
+  def +(other)
+    return Vector.new(@x + other, @y + other)     if other.is_a?(Numeric)
+    return Vector.new(@x + other.x, @y + other.y) if other.is_a?(Vector)
+    self
+  end
+
+  def heading
+    -1 * Math::atan2(-@y, @x)
+  end
+
+  def magnitude
+    @x * @x + @y * @y
+  end
+end
 
-class MultipleParticleSystems < Processing::App
+
+class ParticleSystem < Array
+  include Runnable
+  alias_method :dead?, :empty?
+
+  def initialize(number, origin)
+    super()
+    @origin = origin
+    kind = rand < 0.5 ? Sketch::Particle : Sketch::CrazyParticle
+    number.times { self << kind.new(origin) }
+  end
+end
+
+
+class Sketch < Processing::App
   def setup
     smooth
     color_mode(RGB, 255, 255, 255, 100)
@@ -24,28 +65,12 @@ def draw
   end
 
   def mouse_pressed
-    @particle_systems << ParticleSystem.new(rand(21) + 5, Vector.new(mouse_x, mouse_y))
+    origin = rand(21) + 5
+    vector = Vector.new(mouse_x, mouse_y)
+    @particle_systems << ParticleSystem.new(origin, vector)
   end
-
-  module Runnable
-    def run
-      self.reject! { |item| item.dead? }
-      self.each    { |item| item.run   }
-    end
-  end
-
-  class ParticleSystem < Array
-    include Runnable
-    alias_method :dead?, :empty?
-
-    def initialize(number, origin)
-      super()
-      @origin = origin
-      kind = rand < 0.5 ? Particle : CrazyParticle
-      number.times { self << kind.new(origin) }
-    end
-  end
-
+
+
   class Particle
     def initialize(origin)
       @origin = origin
@@ -76,30 +101,31 @@ def dead?
     end
 
     def render
-      $app.stroke(255, @lifespan)
-      $app.fill(100, @lifespan)
-      $app.ellipse(@origin.x, @origin.y, @radius, @radius)
+      stroke(255, @lifespan)
+      fill(100, @lifespan)
+      ellipse(@origin.x, @origin.y, @radius, @radius)
     end
 
     def render_velocity_vector
       scale = 10
       arrow_size = 4
 
-      $app.push_matrix
-
-      $app.translate(@origin.x, @origin.y)
-      $app.rotate(@velocity.heading)
+      push_matrix
+      
+      translate(@origin.x, @origin.y)
+      rotate(@velocity.heading)
 
       length = @velocity.magnitude * scale
 
-      $app.line 0, 0, length, 0
-      $app.line length, 0, length - arrow_size, arrow_size / 2
-      $app.line length, 0, length - arrow_size, -arrow_size / 2
-
-      $app.pop_matrix
+      line 0, 0, length, 0
+      line length, 0, length - arrow_size, arrow_size / 2
+      line length, 0, length - arrow_size, -arrow_size / 2
+      
+      pop_matrix
     end
   end
-
+
+
   class CrazyParticle < Particle
     def initialize(origin)
       super
@@ -123,44 +149,19 @@ def grow
     end
 
     def render_rotation_line
-      $app.push_matrix
-
-      $app.translate(@origin.x, @origin.y)
-      $app.rotate(@theta)
-
-      $app.stroke(255, @lifespan)
-
-      $app.line(0, 0, 25, 0)
-
-      $app.pop_matrix
-    end
-  end
-
-  class Vector
-    attr_accessor :x, :y
-
-    def initialize(x, y)
-      @x, @y = x, y
-    end
-
-    def +(other)
-      if other.is_a?(Numeric)
-        Vector.new(@x + other, @y + other)
-      elsif other.is_a?(Vector)
-        Vector.new(@x + other.x, @y + other.y)
-      else
-        self
-      end
-    end
-
-    def heading
-      -1 * Math::atan2(-@y, @x)
-    end
-
-    def magnitude
-      @x * @x + @y * @y
+      push_matrix
+
+      translate(@origin.x, @origin.y)
+      rotate(@theta)
+
+      stroke(255, @lifespan)
+
+      line(0, 0, 25, 0)
+
+      pop_matrix
     end
   end
+
 end
 
-$app = MultipleParticleSystems.new :width => 640, :height => 340, :title => 'MultipleParticleSystems'
+Sketch.new :width => 640, :height => 340