A computer player: a process that joins a world as {:robot, n} and plays by its view, deciding every few frames through a brain module the game supplies.

defmodule MyGame.Brain do
  @behaviour Cauldron2D.Robot

  def init(opts), do: %{}
  def decide(view, memory, %{tick: tick, skill: skill}), do: {%{held: MapSet.new([:thrust]), aim: nil}, memory}
  def gone?(view), do: view.me == nil
end

Cauldron2D.Robot.start_link(brain: MyGame.Brain, world: world, number: 1)

decide/3 is given the latest view, the brain's memory and %{tick: n, skill: s}, and returns the input to hold — a Cauldron2D.Input.state/0, or nil to leave the input as it is — with the memory to keep. The input is sent to the world only when it differs from what was last sent. gone?/1 says the robot has no place in the world any more; it then leaves and stops. init/1 is optional; without it the memory starts as nil, and gone?/1 without it is never true.

Every robot has a skill, drawn by skill/0 between 0.3 and 1.0 unless given: it sets how often the robot decides (cadence/2) and is passed to the brain for whatever else the game makes of it.

Options

• :brain — the module. Required
• :world — the world to join. Required
• :number — the robot's number; its id is {:robot, number}. Required
• :brain_opts — given to the brain's init/1. Default []
• :props — merged over %{username: "Robot n", robot?: true} for the join. Default %{}
• :skill — 0.3 to 1.0. Default skill/0
• :cadence — {fastest, slowest}, frames between decisions at full and least skill. Default {3, 9}