balls.rb

# Balls!

class Ball
  attr_accessor :x_pos, :y_pos, :x_speed, :y_speed
  
  def initialize(x_pos, y_pos, x_speed, y_speed)
    self.x_pos = x_pos
    self.y_pos = y_pos
    self.x_speed = x_speed
    self.y_speed = y_speed
  end
end

def setup
  size 800, 600
  @line_count = 5
  @line_speed = 10
  @balls      = []
  
  @line_count.times do 
    @balls << init_ball
  end
end

def range_rand(min, max)
  min + rand(max - min)
end

def init_ball
  x_pos = width / 2 + range_rand(-width / 3, width / 3)
  y_pos = height / 2 + range_rand(-height / 3, height / 3)
  x_speed = range_rand(1, @line_speed)
  y_speed = range_rand(-@line_speed, @line_speed)
  
  Ball.new(x_pos, y_pos, x_speed, y_speed)
end

def draw
  fill 0, 10
  
  rect_mode   CORNER
  rect        0, 0, width, height
  stroke      255
  
  @balls.each do |ball|
    line ball.x_pos, ball.y_pos, mouse_x, mouse_y
    
    # Update Position
    ball.x_pos += ball.x_speed
    ball.y_pos += ball.y_speed
    
    if ball.x_pos >= width || ball.x_pos < 0
      ball.x_speed *= -1
    end
    
    if ball.y_pos >= height || ball.y_pos < 0
      ball.y_speed *= -1
    end
  end
end

def add_ball!
  @balls << init_ball
end

def remove_ball!
  @balls.pop
end

def key_pressed
  case key_code
  when UP
    add_ball!
  when DOWN
    remove_ball!
  end
end