# Inheritance
# 
# A class can be defined using another class as a foundation. In object-oriented
# programming terminology, one class can inherit fields and methods from another. 
# An object that inherits from another is called a subclass, and the object it 
# inherits from is called a superclass. A subclass extends the superclass.
# see also inheritance_two for the use of hash args and inheritance that 
# avoids the inherited class call to super 


def setup    
  size 640, 360
  @arm = SpinArm.new width/2, height/2, 0.01
  @spots = SpinSpots.new width/2, height/2, -0.02, 90.0
end

def draw
  background 204  	
  @arm.display
  @spots.display
end

# vvv CLASS SPIN

class Spin
  
  attr_accessor :x, :y, :speed
  attr_accessor :angle
  
  def initialize(x, y, s)  	    
    @x, @y = x, y
    @speed = s
    @angle = 0.0
  end
  
  def update  	    
    @angle += speed
  end
  
end

# ^^^ CLASS SPIN

# vvv CLASS SPINARM

class SpinArm < Spin # inherit from (or "extend") class Spin
  # NB: initialize inherited from Spin class
  
  def display  		
    stroke_weight 1
    stroke 0  		
    push_matrix  		
    translate x, y
    update
    rotate angle
    line 0, 0, 165, 0
    pop_matrix
  end  	
end

# ^^^ CLASS SPINARM

# vvv CLASS SPINSPOTS

class SpinSpots < Spin    
  attr_accessor :dim  	
  def initialize (x, y, s, d)  	    
    super(x, y, s)
    @dim = d
  end
  
  def display  	    
    no_stroke  		
    push_matrix  		
    translate x, y
    update
    rotate angle
    ellipse(-dim/2, 0, dim, dim) 
    ellipse(dim/2, 0, dim, dim)  
    pop_matrix
  end  	
end

# ^^^ CLASS SPINSPOTS