DragonRuby Game Toolkit - Animation State Machine

player.rb

class Player
  def initialize
    @action_lookup = {
      idle: {
        frame_count: 7,
        dir: "sprites/player/idle",
        repeat: true
      },
      attack: {
        frame_count: 6,
        dir: "sprites/player/attack",
        next_action: :idle
      },
    }

    @action_lookup.each do |k, v|
      v.hold_for ||= 6
      v.default_index ||= 0
      v.duration = v.frame_count * v.hold_for
    end

    @action_lookup
  end

  def action_finished?
    @action_at.elapsed_time > @action_lookup[@action].duration
  end

  def current_action
    @action_lookup[@action]
  end

  def tick
    @next_action = nil

    if args.inputs.keyboard.key_down.space
      @next_action = :attack
    elsif ...
      ...
    end

    if action_finished?
      @next_action = current_action.next_action
    end

    ...

    if @next_action && @next_action != @action
      @action = @next_action
      @action_at = Kernel.tick_count
    end
  end

  def prefab
    frame_index = Numeric.frame_index(start_at: @action_at, **current_action) || current_action.default_index
    path = "#{current_action.dir}/#{frame_index.png}"
    { x: ..., y: ..., path: path }
  end
end