Spinelで動くSnake Game

spinel_snake.rb

class SnakeGame
  WIDTH = 20
  HEIGHT = 10
  MAX_SNAKE_LENGTH = 200

  def initialize
    @field = []
    @snake_x = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
    @snake_y = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
    @snake_length = 3
    @direction = 2  # 0=上, 1=下, 2=右, 3=左
    @food_x = 0
    @food_y = 0
    @score = 0
    @game_over = 0
    @running = 1

    # フィールド初期化（0=空, 1=壁, 2=ヘビ, 3=餌）
    y = 0
    while y < HEIGHT
      x = 0
      while x < WIDTH
        value = (y == 0 || y == HEIGHT - 1 || x == 0 || x == WIDTH - 1) ? 1 : 0
        @field << value
        x += 1
      end
      y += 1
    end

    # ヘビの初期位置（中央）
    @snake_x[0] = 10
    @snake_y[0] = 5
    @snake_x[1] = 9
    @snake_y[1] = 5
    @snake_x[2] = 8
    @snake_y[2] = 5

    place_food
  end

  def run
    setup_terminal
    clear_screen

    # 初期描画
    draw_game

    while @running == 1
      # 非ブロッキングでキー入力チェック
      key = read_key_nonblocking
      if key == "q"
        @running = 0
      elsif key == "w"
        @direction = 0 if @direction != 1  # 下向きでなければ上に変更可
      elsif key == "s"
        @direction = 1 if @direction != 0  # 上向きでなければ下に変更可
      elsif key == "d"
        @direction = 2 if @direction != 3  # 左向きでなければ右に変更可
      elsif key == "a"
        @direction = 3 if @direction != 2  # 右向きでなければ左に変更可
      end

      if @game_over == 0
        move_snake
        draw_game
      else
        @running = 0
      end

      flush_sleep(0.2)
    end

    restore_terminal
    print "\r\n\r\nゲーム終了！\r\n"
    print "最終スコア: "
    print @score
    print "\r\n"
  end

  private

  def setup_terminal
    system("stty raw -echo")
  end

  def restore_terminal
    system("stty -raw echo")
  end

  def clear_screen
    system("clear")
  end

  def flush_sleep(seconds)
    system("")
    system("sleep 0.2")
  end

  def read_key_nonblocking
    # bashのread -tコマンドでタイムアウト付き読み取り
    # -t 0.01 = 0.01秒でタイムアウト、-n 1 = 1文字読み取り
    result = `bash -c 'read -t 0.01 -n 1 key 2>/dev/null && echo $key'`
    result.chomp
  end

  def get_field(x, y)
    @field[y * WIDTH + x]
  end

  def set_field(x, y, value)
    @field[y * WIDTH + x] = value
  end

  def place_food
    # ランダムな位置に餌を配置
    loop do
      # spinelではrand(n)で0〜n-1の整数を返す
      @food_x = rand(WIDTH - 2) + 1
      @food_y = rand(HEIGHT - 2) + 1

      # ヘビと重ならない位置を探す
      occupied = 0
      i = 0
      while i < @snake_length
        if @snake_x[i] == @food_x && @snake_y[i] == @food_y
          occupied = 1
        end
        i += 1
      end

      if occupied == 0
        set_field(@food_x, @food_y, 3)
        break
      end
    end
  end

  def move_snake
    # 新しい頭の位置を計算
    new_x = @snake_x[0]
    new_y = @snake_y[0]

    if @direction == 0
      new_y -= 1
    elsif @direction == 1
      new_y += 1
    elsif @direction == 2
      new_x += 1
    elsif @direction == 3
      new_x -= 1
    end

    # 壁との衝突チェック
    if get_field(new_x, new_y) == 1
      @game_over = 1
      return
    end

    # 自分との衝突チェック
    i = 0
    while i < @snake_length
      if @snake_x[i] == new_x && @snake_y[i] == new_y
        @game_over = 1
        return
      end
      i += 1
    end

    # 餌を食べたかチェック
    ate_food = 0
    if new_x == @food_x && new_y == @food_y
      ate_food = 1
      @score += 10
      @snake_length += 1
    end

    # ヘビを移動（後ろから前に）
    i = @snake_length - 1
    while i > 0
      @snake_x[i] = @snake_x[i - 1]
      @snake_y[i] = @snake_y[i - 1]
      i -= 1
    end

    @snake_x[0] = new_x
    @snake_y[0] = new_y

    # フィールド更新
    update_field

    # 餌を食べたら新しい餌を配置
    if ate_food == 1
      place_food
    end
  end

  def update_field
    # フィールドをクリア（壁以外）
    i = 0
    while i < WIDTH * HEIGHT
      if @field[i] != 1
        @field[i] = 0
      end
      i += 1
    end

    # ヘビを配置
    i = 0
    while i < @snake_length
      set_field(@snake_x[i], @snake_y[i], 2)
      i += 1
    end

    # 餌を配置
    set_field(@food_x, @food_y, 3)
  end

  def draw_game
    # 画面クリアとカーソルをホームに移動
    print "\033[2J\033[H"

    print "=== スネークゲーム ===\r\n"
    print "WASD: 移動, Q: 終了\r\n"
    print "スコア: "
    print @score
    print "\r\n"
    print "\r\n"

    # フィールド描画
    y = 0
    while y < HEIGHT
      x = 0
      while x < WIDTH
        cell = get_field(x, y)
        if cell == 1
          print "ロ"
        elsif cell == 2
          print "巳"
        elsif cell == 3
          print "飯"
        else
          print "　"
        end
        x += 1
      end
      print "\r\n"
      y += 1
    end

    if @game_over == 1
      print "\r\n"
      print "ゲームオーバー！\r\n"
    end

    system("")  # フラッシュ
  end
end

# ゲーム実行
begin
  game = SnakeGame.new
  game.run
rescue Interrupt
  system("stty -raw echo")
  print "\r\n\r\n割り込みで終了\r\n"
end