Issue: Volume: 24 Issue: 3 (March 2001)

Morality Play




In the game black & White, graphics reflect a player's choices about good and evil

By Barbara Robertson

I've asked a lot of people who are crazy about computers just why it is they are so crazy about computers. They will hem and they will haw, but eventually it gets down to this: A computer makes you God."

. . . . .

Steven Levy, now Senior Editor at Newsweek and author of Crypto (Viking), wrote that in 1984 as editor for the games domain in Point Foundation's Whole Earth Software Catalog. A scant three years later, a game developer turned computer users into virtual deities by giving them dominion over a fantasy world.

That developer was Peter Molyneaux, who created the game Populous for his company, Bullfrog. Populous, released in 1987, was arguably the first in what was to become a new genre called god-sims. Maxis' SimCity followed two years later. God-sims tend to tickle the intellect rather than twitch the thumbs, and many of these games have become best sellers. Populous, for example, reportedly has sold 4 million copies and SimCity, 2 million.

This month, if all goes as planned, Electronic Arts will release Lionhead Studios' Black and White, a new god-sim three years in the making that could, if it works as promised, lead the genre into new territory. As before, this game is the brainchild of Peter Molyneaux, who, after selling Bullfrog to Electronic Arts, founded Lionhead and funded the game's development.
Black & White's AI engine can pick from 200 animations to help the simple 3D villagers enact their lives. -- All images courtesy Lionhead Studios.




In a god-sim game, a player manipulates elements in a world, thereby changing the game as it's played. A player might create and populate a city (as in SimCity), direct followers from afar to destroy an enemy (as in the early Populous games), or work through a shaman who interacts with people to give the player-god power and help him or her fight an enemy (as in the later versions of Populous.) Like other god-sims, a player in the new Black and White game enlists the help of people-villagers in this case-to defeat his or her enemies by using magical spells and miracles. But here's the twist: The gameplay in this complex god-sim strategy is based on emotion, not logic.

Black and White takes place in a world dotted with islands; the islands are dotted with villages. Even though the game was designed to run on 200mhz PCs with 4mb graphics cards, the 3D world has moving water, a detailed landscape, and 3D animated characters.

To play the game, you begin by sailing to an island, where you find villagers who treat you as a god. Your job is to convince them to continue worshiping you. You need their prayers to acquire the power to perform miracles, which are the weapons you'll use to fight other gods as you work toward the end goal. The question is, will the villagers worship you because they love you or because they fear you? It's your choice. And those choices will be graded on a scale from good to evil using a system developed by Richard Evans, who came to Lionhead after earning an advanced degree in philosophy from Cambridge University.
A 3D hand controls the speed at which objects such as this rock are moved by virtue of a mouse-based gesture recognition system. A physics engine determines what happens when the rock lands.




For example, early in the game the villagers will ask you to help a woman find her sick brother. You can do that, or decide not to bother with this lesser being, or kill the brother and take the body back to the sister, or do something totally evil: Kill the sister and take her to her dying brother. If you're too benevolent, will the villagers treat you as a peer rather than a god and diminish your status?

In this game, the villagers are the pawns. The most important character is your personal creature-a pet you train using a system of rewards and punishments-that will carry out your wishes, perform miracles, and fight other gods' pets. Two spirits, reminiscent of an angel and devil that would sit on the shoulders of early film characters, try to sway your decisions; in doing so, they provide a narrative for the story. "This is an interactive morality play," says Molyneaux.

Lionhead points to a variety of technical achievements in this game-500 animated villagers, eight different tribes living in separate villages, weather effects, real time raytracing, lapping water, soft shadows, hundreds of little animals and objects with dynamic properties. Especially interesting, though, is the role computer graphics plays in providing feedback to the player by morphing both the landscape and the creatures to continuously but subtly change their appearance.

"Slowly, after many hours of play you'll realize that the world has changed," says Molyneaux. "You are a god. Your world changes to reflect what you are like." If a player primarily makes evil choices, the landscape will become darker and more sinister, and the creature will begin to look demonic. "Nothing ever appears as it was originally created," says Paul McLaughlin, art director.
A player starts with a neutral creature such as a cow. During the game, the creature changes to reflect the player's moral choices, from good (cow at left) to evil (cow at right).




Thus, as the game progresses, the appearance of the landscape and the creature describe the emotional state of the player and can influence the decisions that player makes. If a player's creature begins to breathe fire, the player might think about rewarding the creature for eating grass instead of villagers-or feed it more villagers and create something even nastier.

Nearly all the creatures resemble animals-there's a cow, a tiger, a turtle, and an ape, for example-although all the creatures are bipeds. Each creature morphs in three ways-its mesh (shape) changes, its texture maps change, and its animation changes. The player affects how good or evil the creature becomes, whether it grows fat or becomes thin, and whether it is strong or weak. In addition, the creature grows and ages as time passes. "There are 30 or so obvious differences," says McLaughlin. All of these possibilities combine in various ways to create a unique creature at any one point in time.

McLaughlin used Discreet's 3D Studio Max 2.5 to create several meshes for each creature, starting with a neutral version that he modified and stretched to create extremes for good and evil, fat and thin, young and old. Each mesh has an identical number of polygons and vertices, around 2000 polygons per mesh. Next, he loaded these creatures into Lionhead's in-house editor, which provided a means for combining all the versions to create one mesh. McLaughlin could check the combinations by using sliders to morph the creatures from one extreme to another and then fix problems in Max. "Often when I'd combine thin and weak, a creature's arms would get too thin," he says. So he'd adjust the meshes for the two extreme shapes to make each a little bigger.

Once the meshes were completed, McLaughlin began applying textures using 256- by 256-pixel texture maps for the morph from good to evil-the UV coordinates remain consistent as the mesh morphs from one extreme to another. Each character also has textures for bruising, scarring, bleeding...and tattoos. A player can choose from eight predefined tattoos or create a custom design in Adobe Systems' Photoshop and apply that to the pet.

In addition to the real-time mesh and texture morphing, each creature's animation also must morph to accommodate changes in the mesh. While creating and blending animations such as walks to runs is nothing new in games, Scawen Roberts, who wrote parts of the 3D graphics engine, was given the challenge of working with a character that would have an ever-changing physical shape. "The evil creatures are bent over," he says. "It was clear that the animation had to morph as well."
A trained creature can cast spells (top left) and fight other gods' creatures (top right). On its own, a hungry creature will search for food (bottom left). If trained to eat villagers rather than grass, it begins to look demonic, as does this turtle




Roberts created a skeletal system that is used to animate every character in the game, whether the animation is created with key frames or generated by the AI engine. This skeletal system is adaptable. All the characters adjust to environmental changes and personal changes-a hill causes a character to lean as it walks, an injury affects the way a body part moves. In addition, each creature's animation is altered to accommodate changes in physique caused by morphing. Roberts accomplished this with linear blends between keyframes using animation matrices for each bone in each version of the creature-neutral, evil, good, fat, thin, and so forth.

All during the game, Evans' AI engine tells the creature what it looks like and what to do. "His code is very complex; it's the brain," Roberts says. "My system is the body. It waits to be told what to do." For example, using Evans' AI system, the creature remembers if it's hungry. If it is, the system remembers which foods satisfy the hunger and tells the creature to find the nearest source. Roberts' code in the graphics engine then determines how the creature will get to the food. To make a creature turn around, the AI engine gives the graphics engine a point for the creature to look at; Roberts' engine moves the creature's head and calculates its route.

Moving the creature automatically to a food source can be a complex undertaking. "First, the system checks all the squares in the map between 'here and there,' puts circles around objects to avoid, chooses the shortest route, smoothes the curve, and then the creature runs off," explains Roberts.

The landscape is created with a conventional height field, according to McLaughlin, mapped with 256- by 256-pixel resolution textures. "It's like a checkered tablecloth placed over things on a table," he says. Each of the islands has a different geography and different earth-like features, ranging from grassy plains to swamps. During the game, the player might zoom in to a four inch-square area of the texture map, or zoom out far enough to see an area five miles across. Extra layers of detail are used for close-up views, and noise filters combined with bump maps help give the landscape a natural randomness. In addition, to give the landscape a more organic feel, programmer Jean-Claude Cottier created a system that blends textures so that, for example, when rocks meet water, the player doesn't see the texture tiles.

The changes to the landscape that reflect the player's moral choices are accomplished partly with textures-grass turns brown, for example, and the sky gets dark-and also by the addition of such elements as birds and rainbows to express goodness, and bats to suggest evil.

To move across the landscape-in fact, to go anywhere or do anything, the player works with a remarkably simple interface, an icon of a hand on the screen. "Our target was to make the game playable within 15 seconds," says Molyneaux. "It was so tempting to put icons on the screen, though."

Instead, they invented a gesture-recognition system that understands how fast the mouse is moving and uses that information to distinguish between actions such as tossing a rock gently or hurling it with the intention of inflicting damage. With the addition of a mouse that incorporates Immersion's TouchSense technology (such as Logitech's iFeel Mouse), the player can get tactile sensations as well. Along with other effects and sensations, a player using this technology can feel the creature's fur while stroking it or feel the effect of slapping the creature. Those two actions, in particular, are ones a player uses to reward or punish a creature and thus train it.

It is, finally, the creature that most vividly embodies the player's emotions and moral choices. "When you meet a creature and see its world, you know what that creature is like, " says Molyneaux. And, it could be easily argued, you know something about its creator, too.
After hours of play, a lush, green, neutral landscape (top left) becomes parched and brown (top right) and then sinister and fiery (bottom left), reflecting choices the system graded as "bad." The temple (bottom right) houses a creature's cave and suc




"The idea for this came from realizing that when someone comes into a room, you make an instant call," says Molyneaux. "That's what we're trying to get. The big payoff comes when you go online with your creature."

When a creature is a year old in game terms, it gets an overwhelming urge to create a Web site. There, in the Black and White online world, you can see other people's creatures and they can see yours. While online, the creatures can cooperate or compete... and change. Even so, your creature can still pop back into your offline story, according to Molyneaux.

"We wanted to give someone the ability to show off his nasty overweight cow with a tattoo and sunglasses to others," says McLaughlin. And if they don't like the creature they created? "It can take a lot to pull a creature back from an extreme," he says. Which makes this god-sim a little like real life. Whether an interactive morality play will hold the interest of gamers remains to be seen. But if early attention is any indication, then computer graphics will have helped move an already interesting game genre into a new dimension, and Molyneaux will have another hit on his hands.

Barbara Robertson is Senior Editor, West Coast for Computer Graphics World.
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