Carnival#

This environment is part of the Atari environments. Please read that page first for general information.


Action Space	Discrete(18)
Observation Space	(214, 160, 3)
Observation High	255
Observation Low	0
Import	`gymnasium.make("ALE/Carnival-v5")`

Description#

This is a “shoot ‘em up” game. Targets move horizontally across the screen and you must shoot them. You are in control of a gun that can be moved horizontally. The supply of ammunition is limited and chickens may steal some bullets from you if you don’t hit them in time. Detailed documentation can be found on the AtariAge page.

Actions#

By default, all actions that can be performed on an Atari 2600 are available in this environment. However, if you use v0 or v4 or specify full_action_space=False during initialization, only a reduced number of actions (those that are meaningful in this game) are available. The reduced action space may depend on the flavor of the environment (the combination of mode and difficulty). The reduced action space for the default flavor looks like this:

Num	Action
0	NOOP
1	FIRE
2	RIGHT
3	LEFT
4	RIGHTFIRE
5	LEFTFIRE

Observations#

By default, the environment returns the RGB image that is displayed to human players as an observation. However, it is possible to observe

The 128 Bytes of RAM of the console
A grayscale image

instead. The respective observation spaces are

Box([0 ... 0], [255 ... 255], (128,), uint8)
Box([[0 ... 0] ... [0 ... 0]], [[255 ... 255] ... [255 ... 255]], (250, 160), uint8)

respectively. The general article on Atari environments outlines different ways to instantiate corresponding environments via gymnasium.make.

Rewards#

You score points by destroying targets. Points (or bullets) may be subtracted if you hit the target when it shows a minus sign. You will score extra points if it shows a plus sign! For a more detailed documentation, see the AtariAge page.

Arguments#

env = gymnasium.make("ALE/Carnival-v5")

The various ways to configure the environment are described in detail in the article on Atari environments. It is possible to specify various flavors of the environment via the keyword arguments difficulty and mode. A flavor is a combination of a game mode and a difficulty setting.

Environment	Valid Modes	Valid Difficulties	Default Mode
Carnival	`[0]`	`[0]`	`0`

You may use the suffix “-ram” to switch to the RAM observation space. In v0 and v4, the suffixes “Deterministic” and “NoFrameskip” are available. These are no longer supported in v5. In order to obtain equivalent behavior, pass keyword arguments to gymnasium.make as outlined in the general article on Atari environments. The versions v0 and v4 are not contained in the “ALE” namespace. I.e. they are instantiated via gymnasium.make("Carnival-v0").

Version History#

A thorough discussion of the intricate differences between the versions and configurations can be found in the general article on Atari environments.

v5: Stickiness was added back and stochastic frameskipping was removed. The entire action space is used by default. The environments are now in the “ALE” namespace.
v4: Stickiness of actions was removed
v0: Initial versions release (1.0.0)