ANGELINA - Coevolution in Automated Game Design
Michael Cook and Simon Colton
Computational Creativity Group, Imperial College, London (ccg.doc.ic.ac.uk)
Figure 1: Screenshot from a game about a murdered aid
worker from Scotland. The background image is of the Scottish
landscape, and a red ribbon image has been selected to
represent the aid charity.
ANGELINA
ANGELINA is a co-operative co-evolutionary system for
automatically creating simple videogames. It has previously
been used to design both simple arcade-style games and twodimensional
platformers. In the past, ANGELINA’s efforts
have been focused on mechanical aspects of design, such as
level creation, rule selection and enemy design. We are now
in the process of expanding ANGELINA’s remit to cover
other aspects of videogame design, including aesthetic problems
such as art direction and the selection and use of external
media to evoke emotion or communicate meaning.
ANGELINA has produced several new games for this
demonstration, exemplifying the new abilities the system
now has. Its co-operative co-evolutionary system for platform
games is composed of four modules: (i) a level designer
that places solid blocks and locked doors to shape the
progress of the player (ii) a layout designer that places and
designs the enemies the player faces, as well as the start and
end of the level (iii) a powerup designer that defines what
bonus items the player can acquire during gameplay and (iv)
a creative direction module that arranges a set of media resources
in the level for the player to discover during gameplay.
This latter module is the newest addition to the system,
and takes advantage of many new capabilities built into ANGELINA
for retrieving content from the web dynamically
for use in themed videogames.
Design Task
Inspired by the collage-creation problem described in (Cook
and Colton 2011) ANGELINA obtains current affairs articles
by accessing the website of the British newspaper The
Guardian. It selects a news story, and attempts to design a
short platform game whose theme is inspired by the news article
selected. Currently, this allows ANGELINA to demonstrate
simple abilities such as the appropriate selection of
media from a wide variety of sources, and arrangement in a
potentially nonlinear level space.
Figure 2: Media retrieved for a game inspired by an inquiry
into a newspaper. Left: an image retrieved using the
phrase ’newspapers and magazines’. On the right is Rebekah
Brooks, one of the journalists in the investigation.
ANGELINA uses online knowledge sources such as
Wikipedia to extract additional information about data retrieved
from the news articles - it can, for instance, identify
when a country is the subject of a news article, allowing
the system to search photography websites such as Flickr
for photographs of that country to use as a backdrop to the
game. Keyword-based searches can also be augmented with
emotional keywords to alter the results they return, based on
techniques described in (Cook and Colton 2011). By reading
live Twitter search results about a named person in the
news article, ANGELINA can use search augmentation appropriate
to the opinions it finds to retrieve media that reflect
perceived public opinion of a particular topic. Although a
simple technique, it is a first step towards the system dealing
with opinion and bias through the work it produces.
Games
The games produced are simple platform games, loosely following
the design tenets of the Metroidvania subgenre. The
player must navigate the level space to reach the exit, but in
order to gain access to later level sections, it is necessary to
seek out and obtain items that add to the player’s capabilities
(for example: unlocking doors or changing the player’s
jumping abilities). As the player explores further they will
encounter enemies, as well as images and sound content that
is appropriate to the game’s theme.
ANGELINA is implemented in Java, but the games the
system produces are Flash-based. When ANGELINA has
evolved a game design, it modifies an existing ActionScript
game template to include the generated design content, as
well as incorporating the media downloaded and selected
from the internet. All of the games available in the demonstration,
as well as others developed by the system, are available
on the project website: www.gamesbyangelina.org
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References
Cook, M., and Colton, S. 2011. Automated collage generation
- with more intent. In Proceedings of the Second
International Conference on Computational Creativity.
International Conference on Computational Creativity 2012 228