Saturday, September 1, 2007

Celestial Music

Yesterday morning I woke up from one of those startlingly lucid dreams where I was playing a completed game design. I tell my wife that odd ideas are like exotic fruit and if you fail to jot them down, they will rot away, never to be tasted again. So here are my quickly captured notes of what is, literally, a dream game of mine. :-)

Imagine, if you will, a space strategy game. You start out with a single planet surrounded by hostile enemy planets. Your goal is to clear the map of enemies and create a galaxy spanning civilization. All pretty standard stuff.

The difference is that you fight and grow using music that you compose by building your empire. This is where it gets trippy.

Planets as sequencers
Watch this movie clip of a multi-touch music creation tool. It is wonderfully bizarre.

The basic gist, multi-touch madness aside, is that smart objects positioned on a flat screen can be used to create music. Link them together using a directed graph and you have a pretty competent music sequencer and sound effects generator.

The game design leap is that these objects can also be planets in a strategy game. Each planet has a different effect.

  • Forest planets are sources for sound effects
  • Water planets are filters for distorting a sound.
  • Cities planets are sequencers for taking a sound stream and playing it out over time.
Throughout the design, you’ll see that every element can be seen in two ways. One is as an element of a song. Two is as part of a game.

Linking planets
Each planet has a space port. You can drag a space lane from a space port to another nearby planet.

In the process, you connect a sound source to a sound processor. In very short order, just by linking up space lanes, you can create a giant sequenced sound machine. At the same time, you are directing trade and setting up your space empire.

Setting properties on planets

Each planet is a fanciful user interface that lets you adjust the properties of the filter.
  • Planets have a sun. You can adjust the time it takes for the sun to go around the planet in order to adjust the timing of how long a sound plays. In the game this is described as planetary engineering
  • Distance from the other planets effect the volume of the source sound effect.
  • City planets allow you to adjust the height of the cities, thus allowing you to adjust how you sequence a sound source.

Music = culture = resource
Each planet produces a sound. Some generate sounds. Others take in sounds and modify them. The stream of sounds produced by your planets is what most folks would call music. It also represents ‘culture’ in the game. Culture is the resource that makes everything in the game work.

Culture pools in planets that are the final destination of sound streams. They collect it in real time. Culture can be spent on upgrading your planets and creating war ships, defending against attacks.

The enemy does not sleep
You are not alone in the universe. There are other planets on the fringes of your empire. They send ships to destroy your civilized worlds and knock them back into desolate husks. They’ll disturb your carefully calculated rhythms, disrupt trade routes and generally cause your empire to devolve into chaos, then silence.

If a planet is attacked enough, it will be turned into a dead world, devoid of music.

Spending culture
Luckily, you can use your culture to both defend, fight back and ultimately conquer the enemy planets.

Some planets have industrial complexes. An activated industrial complex sucks in culture and converts it into ones of three main types of ships
  • Defenses: The planet builds a shield for fending off enemy attacks. It can take X damage per second. Defenses tend to beat equally matched ships.
  • Attack ships: The planet can send out a stream of attack ships. If the planet is poorly defended, the planet is slowly bombed into the stone age and reduced to a simple forest planet.
  • Ambassadors: Ambassadors convert dead planets into player planets.
At first you defend against attacks. Then you fight back. Eventually you conquer the enemies and make their worlds yours.

The benefits of conquest
Conquest is great. Capturing new worlds allow you to build more complex sequences of sound. This means more interesting songs. It also means that culture accumulates faster and allows you to expand your empire further.

Some planets have tidbits of plot, mysteries, single use powerups, treasures and other rewards. Conquest advances the player in the game.

Culture is multiplied by audience appreciation
An empire is a song. As a song it can be shared with your friends outside of the game. At any point, you can send a link to your empire to a friend. They can check it out and simply by the act of listening to your song, your empire gains marvelous bonuses.

If they like, your friends can rate the song. This gives you even more bonus culture. If they like the style of your songs, they can subscribe to your various empires. This gives you even more bonus. By sharing your creations with the outside world, you gain resources that let you advance your single player game.

A game that encourages the creation of great songs
The game is balanced to encourage this. During the early stages of creating your empire, there is enough culture in random combinations of planets to conquer a fair portion of the map. Eventually, you start running out of culture. You’ll come across powerful enemies that you cannot defeat unless you start sharing your songs with others.

Good songs, as judged by an audience of your peers, will gain you greater rewards than random garbled messes of sound. Judging music is hard for a computer. However, it is easyier for people. The design harnesses your friends as our AI judgment algorithm to encourage and reward the user to become a great composer.

Some maps can be explored and beaten if the player creates songs that are enjoyed by one or two people. Other maps require that the player create songs that are loved by hundreds.

The enemy as a tutorial
The map creation for the game is tricky since it serves two purposes. The first is to provide a challenge to the player. This is pretty straight forward level design and deals with choke points, resources, power ups etc.

The second, more devious goal, is to teach the player compositional structures. The enemy worlds are a nodal graph of a song just like the player’s worlds are a graph of a song. The level designer composes the enemy empire as a song.

All the various tricks of making a song are there for the player to see. The way that you distort a basic sound into something intensely cool. The way that you use a sequencer plus a snare sample to create the beat. All of it is visually laid out as a working model for the player.

When the player conquers the enemy worlds, they are essentially deconstructing the level designer’s song filter node by filter node. The player is then asked to put their newly acquired node to use. The easiest thing would be to replicate what was already done.

What we have is an experiential lesson in music composition masquerading as a game.
  • The player observes a functional model.
  • They dissect the model to understand its parts
  • They are required to reassemble the model and make it work again.
  • They are rewarded for making something better than the original.
I finally got around to reading Rules of Play by Katie Salen and Eric Zimmerman. The tome repeatedly emphasizes that you can analyze a single game through multiple perspectives. Celestial Music is a game that is two things simultaneously. It is a strategy and it is a music creation tool. It is also, by the fact that is both of these things, a system for exploring and learning music in a user friendly manner.

Games lubricate experiential learning about a system. Plunk an inexperienced person down in front of a piano and some sheet music and they will become frustrated. Sit that same person down in front of a game like Celestial Music and they will slowly learn. The result may not be Mozart, but it will certainly be music.

As I awoke groggily from my dream yesterday, I was left with the amazing memory of playing this quirky game. Sound and visuals flowed throughout the screen like some clockwork instrument pulse with life. There was no real distinction between building something beautiful and playing an enthralling game. Delightful.

Take care


Human computation
Humans are far better at some activities than computers. Luis von Ahn is a computer scientist at Carnegie Mellon that studies how to tap into the abilities of people to solve hard problems like image recognition or human identification. He uses games as his medium. The fact that people are better than computers at determining what is meaningful music is leveraged in the Celestial Music design.

The Rules of Play
I rather enjoyed this book's emphasis on the Magic Circle and how it interacts with culture at large.