Detect Empo from a game

The Ruby globals that tell a game script that Empo runs it, and which Empo version runs it.

Empo sets three Ruby globals before the first script of a game runs. A script can read them to find out that Empo runs the game.

Which games get them

Check that Empo runs the game

if $empo
  # Empo runs the game.
end

On a launcher that does not set $empo, the global is nil, so the check is false.

Check the Empo version

$userAgentVersion has three numbers with a period between each, for example "0.11.0". Compare the numbers, not the strings: as strings, "0.9.0" is greater than "0.11.0".

def empo_at_least?(*wanted)
  parts = $userAgentVersion.to_s.split('.').map { |part| part.to_i }
  (parts <=> wanted) >= 0
end

if empo_at_least?(0, 11, 0)
  # Empo 0.11.0 or later runs the game.
end

Versions of Empo before the global existed do not set it, so it is nil. The example above reads nil as a version lower than all others.

Do not read the version out of $userAgent. Other scripts use $userAgent as a name, so it stays the name only.

The engine version is a different value

In RPG Maker XP, VX, and VX Ace games, System::VERSION is the version of the game engine inside Empo, not the version of Empo. One Empo version can change its engine, and the engine version uses a different format. To check Empo, use $userAgentVersion.