Breakout made quickly

main.rb

$gtk.reset

def tick args
  defaults args
  handle_input args
  calc args
  render args
end

def handle_input args
  args.state.bat_x = args.mouse.x - (args.state.bat_w / 2)
  args.state.ball_active = true if args.mouse.click
  if args.inputs.keyboard.key_down.space
    $gtk.reset
  end
end

def defaults args
  args.state.num_cols ||= 16
  args.state.num_rows ||= 8
  args.state.brick_width ||= 80
  args.state.brick_height ||= 40
  args.state.bricks ||= make_bricks args

  args.state.ball_size ||= 20
  args.state.ball_x ||= (args.grid.w - args.state.ball_size) / 2
  args.state.ball_y ||= 60
  args.state.ball_active ||= false
  args.state.ball_speed_x ||= 4
  args.state.ball_speed_y ||= 4

  args.state.bat_x ||= -1000
  args.state.bat_y ||= 40
  args.state.bat_w ||= 100
  args.state.bat_h ||= 20

end

def calc args
  return unless args.state.ball_active

  next_x = args.state.ball_x + args.state.ball_speed_x
  next_y = args.state.ball_y + args.state.ball_speed_y
  next_ball_rect = [next_x, next_y, args.state.ball_size, args.state.ball_size]
  bat_rect = [args.state.bat_x, args.state.bat_y, args.state.bat_w, args.state.bat_h]

  # bounce on walls
  args.state.ball_speed_x = 0 - args.state.ball_speed_x unless (0..1260) === next_x
  # args.state.ball_speed_y = 0 - args.state.ball_speed_y unless (0..700) === next_y

  args.state.ball_speed_x = 0 - args.state.ball_speed_x if 720 < next_y

  if next_y < 0
    $gtk.reset 
    return
  end

  # HIT DETECTOR
  hit_brick = false

  top_bottom_hits = 0
  left_right_hits = 0

  args.state.bricks.map_2d do |col, row, brick|
    next if brick == []

    if brick.intersect_rect? next_ball_rect

      args.state.bricks[col][row] = []
      hit_brick = true

      # check the last position of the ball
      # keep track of the numbers of horizontal or vertical sides the ball crossed
      # if the ball's top or bottom is outside of the brick, it crossed a horizontal
      top_bottom_hits += 1 if args.state.ball_y + args.state.ball_size <= brick[1] ||
                              args.state.ball_y >= brick[1] + brick[3]
      # if the ball's left or right is outside of the brick, it crossed a vertical
      left_right_hits += 1 if args.state.ball_x + args.state.ball_size <= brick[0] ||
                              args.state.ball_x >= brick[0] + brick[2]
    end
  end

  if hit_brick
    # puts [left_right_hits, top_bottom_hits]
    # bounce x
    # if the ball crossed 1 horizontal, no vertical (it hit one brick)
    # or the ball crossed 2 horizontals, 0-1 vertical (it hit two bricks side by side)
    if left_right_hits > top_bottom_hits
      ball_bounce(args, true, false)
    # bounce y
    # if the ball crossed 1 vertical, no hotizontal (it hit one brick)
    # or the ball crossed 2 verticals, 0-1 horizontal (it hit two bricks, one on top of the other)
    elsif top_bottom_hits > left_right_hits
      ball_bounce(args, false, true)
    # bounce x and y
    # if the ball crossed 1 vertical and 1 horizontal 
    # (it hit the corner of 1 brick, or the corner between 2 bricks)
    else
      ball_bounce(args, true, true)
    end
  end

  # hit bat
  if bat_rect.intersect_rect? next_ball_rect

    top_bottom_hits = 0
    left_right_hits = 0

    bounce_y = args.state.ball_y + args.state.ball_size <= bat_rect[1] ||
               args.state.ball_y >= bat_rect[1] + bat_rect[3]
    bounce_x = args.state.ball_x + args.state.ball_size <= bat_rect[0] ||
               args.state.ball_x >= bat_rect[0] + bat_rect[2]

    # do something if the ball hits near the end of the bat
    bat_strike_point = next_x - bat_rect[0]

    if bat_strike_point < 20
      args.state.ball_speed_x -= 0.5
    end

    if bat_strike_point > bat_rect[2] - args.state.ball_size
      args.state.ball_speed_x += 0.5
    end

    ball_bounce(args, bounce_x, bounce_y)
  end
  
  args.state.ball_x = next_x
  args.state.ball_y = next_y
end

def ball_bounce(args, bounce_x, bounce_y)
  args.state.ball_speed_x = 0 - args.state.ball_speed_x if bounce_x
  args.state.ball_speed_y = 0 - args.state.ball_speed_y if bounce_y
end

def make_bricks args
  args.state.bricks = args.state.num_cols.times.map do |c| 
    args.state.num_rows.times.map do |r|
      [
        c * args.state.brick_width,
        720 - (r + 1) * args.state.brick_height,
        args.state.brick_width,
        args.state.brick_height,
        'sprites/square/green.png'
      ]
    end
  end
end

def render args
  args.outputs.sprites << [
    args.state.ball_x, 
    args.state.ball_y,
    args.state.ball_size, 
    args.state.ball_size, 
    'sprites/square/red.png'
  ]
  args.outputs.sprites << [
    args.state.bat_x, 
    args.state.bat_y,
    args.state.bat_w,
    args.state.bat_h,
    'sprites/square/blue.png'
  ]
  args.outputs.sprites << args.state.bricks
end