How to create multiple consecutive commands with ECSx?

Hi Miguel! When using ClientEvents, try to make each event line up with a single input from the user. So, let’s say you have a button which can be clicked by the user to move north, and one button click always equals 10 “positions” on the map. The ClientEvent in this case would just be :move_north - and the distance moved is only a concern for the ClientEventHandler:

def Ship.Systems.ClientEventHandler do
  ...
  @move_distance 10

  defp process_one({player, :move_north}) do
    y = YPosition.get(player)
    YPosition.update(player, y + @move_distance)
  end
end

Now, if you have a button where sometimes a press moves 10 positions, and other times a press moves 5 positions, the question is: what determines this value? If the value comes from the frontend, such as a slider in the UI where the user adjusts the speed, then we’ll attach that value as metadata with the event:

ClientEvents.add(player_entity, {:move_north, 10})
ClientEvents.add(player_entity, {:move_north, 5})

and the handler:

defp process_one({player, {:move_north, value}}) do
  y = YPosition.get(player)
  YPosition.update(player, y + value)
end

But if the value is based in the backend (stored as a component somewhere) then metadata should not be used. For example, if one button press equals s positions, where s is the SailingSpeed of the player’s ship, simply add :move_north and fetch the value in the handler:

defp process_one({player, :move_north}) do
  y = YPosition.get(player)
  value = SailingSpeed.get(player)
  YPosition.update(player, y + value)
end

Hope this helps, happy to answer any other questions you might have!

Hi Andy, I appreciate the quick response, you surprised me!
I understood the concept perfectly. However, I don’t see a way to change the dynamic, I want to implement multiple actions concatenated from a simple user event, for example with a text input.
I think the problem is in the update cycle between the frontend and backend.
Any ideas you can give me will be welcome!
Thank you in advance..

Remember, you want one ClientEvent for each user event. In this case we have:

• 1 simple user event on the frontend

def handle_event("liveview_event", params, socket) do
  ...
  ECSx.ClientEvents.add(player_entity, {:simple_user_event, maybe_metadata})
  ...
end

• multiple actions on the backend

def Ship.Systems.ClientEventHandler do
  ...

  defp process_one({player, :simple_user_action, metadata}) do
    do_action_1()
    do_action_2()
    do_action_3()
    ...
  end
end

Great Andy, this works! Now, to up level, any idea to aggregate sound?
I hope your comments! Thank you from yet!

Playing audio is mostly a job for the client - so it depends on what type of frontend you are using. If it’s a web game in the browser, maybe start with looking into Using the Web Audio API - Web APIs | MDN

Ok, let’s go for this! Thank you very much!