amethyst/apps/example_game/lib/example/game.ex

defmodule Example.Game do
  require Logger
  @behaviour Amethyst.Game

  @moduledoc """
  Example game used for testing Amethyst.
  """
require Amethyst.NBT.Write
alias Amethyst.NBT

  @impl true
  def instantiate(supervisor) do
    Logger.info("The supervisor for this game is at #{inspect(supervisor)}")
    {:ok, %{}}
  end

  @impl true
  def login(from, cfg, refs) do
    Logger.info("Player logged in from #{inspect(from)}: #{inspect(cfg)}")
    Logger.info("The refs for this game are #{inspect(refs)}")
    {:accept, {0.0, 270.0, 0.0}, {0.0, 0.0}}
  end

  @impl true
  @spec player_position(any(), {any(), any(), any()}, any()) :: :ok
  def player_position(from, {x, y, z}, _refs) do
    # Logger.info("Player at #{inspect(from)} moved to #{x}, #{y}, #{z}")
    send(from, {:set_position, {x, y, z}})
    :ok
  end

  @impl true
  def player_rotation(_from, {_yaw, _pitch}, _refs) do
    # Logger.info("Player at #{inspect(from)} rotated to #{yaw}, #{pitch}")
    :ok
  end

  @impl true
  def accept_teleport(from, id, _state_refs) do
    Logger.info("Player at #{inspect(from)} accepted teleport #{inspect(id)}")
    :ok
  end

  @impl true
  def chat(from, message, _state_refs) do
    Logger.info("Player at #{inspect(from)} said: #{inspect(message)}")
    send(from, {:send_packet, %{
      packet_type: :system_chat_message,
      content: NBT.Write.compound(%{"text" => NBT.Write.string("You said: #{message}")}),
      overlay: false
    }})
    :ok
  end

  @impl true
  def joinable?(_refs) do
    true
  end


  @impl true
  def chunk(_from, {cx, cz}, _state_refs) do
    # Logger.info("Player at #{inspect(from)} wants to know chunk #{cx}, #{cz}")
    (0..255) |> Enum.map(fn y ->
      (0..15) |> Enum.map(fn z ->
        (0..15) |> Enum.map(fn x ->
          gx = cx * 16 + x
          gz = cz * 16 + z
          gy = y
          if rem(gx, 4) == 0 && rem(gy, 4) == 0 && rem(gz, 4) == 0 do
            {abs(rem(div(gx + gy + gz, 4), 300)), 7, 7}
          else
            {0, 7, 7}
          end
        end)
      end)
    end)
  end
end