A baseball game for PC. (under construction...)

persosta.rb

require "gosu"

module Persosta
  module ZOrder
    Background, Ball, Bat = *0..2
  end

  module Base
    def draw_square(window, x1, y1, x2, y2, color, z_order=0)
      window.draw_quad(x1, y1, color,
                       x2, y1, color,
                       x1, y2, color,
                       x2, y2, color,
                       z_order)
    end

    def draw_frame(window, x1, y1, x2, y2, color, z_order=0)
      window.draw_line(x1, y1, color,
                       x2, y1, color,
                       z_order)
      window.draw_line(x1, y1, color,
                       x1, y2, color,
                       z_order)
      window.draw_line(x1, y2, color,
                       x2, y2, color,
                       z_order)
      window.draw_line(x2, y1, color,
                       x2, y2, color,
                       z_order)
    end

    def hit?(x, y)
      x >= @x1 && x <= @x2 &&
      y >= @y1 && y <= @y2
    end
  end

  class Bat
    include Base

    attr_reader :x, :y
    attr_writer :swinging

    def initialize(window, base_x, base_y, max_y, image_path=nil)
      @window = window
      @base_x = base_x
      @base_y = base_y
      @x = @base_x
      @y = @base_y
      @max_y = max_y
      @central_x = @window.width * 0.8
      @central_y = (@base_y + @max_y) / 2
      @radius = @window.height * 0.02
      @angle = 0
      @speed = @window.height * 0.02
      @moving = true
      @swinging = false
      if image_path
        @image = Gosu::Image.new(@window, image_path, false)
      end
    end

    def move
      return unless @moving
      if @swinging
        return if @y <= @max_y
        @y += Gosu.offset_y(@angle, @speed)
      else
        return if @y >= @base_y
        @y -= Gosu.offset_y(@angle, @speed)
      end
    end

    def draw
      if @image
        @image.draw(@x - @radius,
                    @y - @radius,
                    ZOrder::Bat,
                    2.0 * @radius / @image.width,
                    2.0 * @radius / @image.height)
      else
        color = Gosu::Color::BLACK
        @window.draw_line(@x - @radius * 3, @y,         color,
                          @central_x,       @central_y, color,
                          ZOrder::Bat)
      end
    end

    def meet?(ball)
      return unless @swinging
      return if @y <= @max_y
      Gosu::distance(@x, @y, ball.x, ball.y) < (@window.height * 0.02)
    end

    def reflect_angle
      (@central_y - @y) * (@window.height * 0.02)
    end
  end

  class Ball
    include Base

    attr_reader :x, :y
    attr_accessor :flying

    def initialize(window, image_path=nil)
      @window = window
      @x = @y = 0.0
      @ball_radius = @window.height * 0.02
      @angle = 180
      @speed = @window.height * 0.02
      @moving = true
      @flying = false
      if image_path
        @image = Gosu::Image.new(@window, image_path, false)
      end
    end

    def draw
      if @image
        @image.draw(@x - @ball_radius,
                    @y - @ball_radius,
                    ZOrder::Ball,
                    2.0 * @ball_radius / @image.width,
                    2.0 * @ball_radius / @image.height)
      else
        draw_square(@window,
                    @x - @ball_radius, @y - @ball_radius,
                    @x + @ball_radius, @y + @ball_radius,
                    Gosu::Color::WHITE, ZOrder::Ball)
        draw_frame(@window,
                   @x - @ball_radius, @y - @ball_radius,
                   @x + @ball_radius, @y + @ball_radius,
                   Gosu::Color::BLACK, ZOrder::Ball)
      end
    end

    def warp(x, y)
      @x, @y = x, y
    end

    def move
      return unless @moving
      @x += Gosu.offset_x(@angle, @speed)
      @y += Gosu.offset_y(@angle, @speed)
    end

    def reflect(bat)
      @angle += 180
      @angle %= 360
      @angle += bat.reflect_angle
      @speed *= 2
    end
  end
  
  class Window < Gosu::Window
    include Base

    def initialize
      super(240, 240, false)
      self.caption = "Persosta"
      @ball = Ball.new(self)
      @ball.warp(self.width * 0.5, self.height * 0.2)
      @bat = Bat.new(self,
                     self.width * 0.5,
                     self.height * 0.9,
                     self.height * 0.7)
    end

    def update
      @ball.move
      if button_down?(Gosu::KbSpace) ||
         button_down?(Gosu::MsLeft)
        @bat.swinging = true
      else
        @bat.swinging = false
      end
      @bat.move
      if (not @ball.flying) && @bat.meet?(@ball)
        @ball.flying = true
        @ball.reflect(@bat)
      end
    end

    def draw
      draw_field
      @ball.draw
      @bat.draw
    end

    def button_down(id)
      case id
      when Gosu::Kb1
        @ball = Ball.new(self)
        @ball.warp(self.width * 0.5, self.height * 0.2)
      when Gosu::KbEscape
        close
      end
    end

    private
    def draw_field
      draw_square(self,
                  0, 0,
                  self.width, self.height,
                  Gosu::Color::WHITE, ZOrder::Background)
    end
  end
end

window = Persosta::Window.new
window.show