Persuasive Games: Texture
May 7, 2008 Page 2 of 4
Texture in Video Games
In the era of 3D computer graphics, texture is a term frequently used in technical talk about video games. Textures are the graphical skins laid atop 3D models so they appear to have surface detail.
Texturing techniques like bump mapping and normal mapping use two-dimensional image data to perturb the lighting patterns applied to objects by 3D rendering algorithms to make them appear to have a surface texture that is not actually present in the 3D model itself.
These simulate the appearance, but not the behavior or sensation of texture. This is nothing new; the fine arts have often done similar.
Surrealist Réne Magritte was particularly adept at creating the appearance of texture in his subjects with color and tone rather than paint thickness.
In Magritte's "Le modèle rouge," the texture of the wood slats and the dirt ground jump out as familiar textures, despite the flatness of the artist's brush technique.
Epic Games' Gears of War -- it's all about the texture(s)
But unlike paintings and plats principaux, games are not static scenes or objects -- they are interactive models of experiences. To simulate the behavior, rather than just the appearance of texture, games have to use more than visual effects.
Sound design is one answer: footfalls or bullet casings can produce different noises when falling on grass, dirt, concrete, wood.
A character wading through tall grasses causes the blades to swoosh around him. When steered off the road, a car's tires grind against gravel.
Simulated properties of the physical world can also contribute to texture. A game might slow a character's movement through brush or swamp, as do both realistic first-person shooters like Far Cry and abstract strategy games like Advance Wars.
Likewise, driving games from Pole Position to Burnout alter a vehicle's speed and handling when it moves across different surfaces, simulating the differences in traction. Friction is another frequently simulated texture: platformer games like Ice Climber simulate the reduced friction of ice-covered surfaces.
In all these cases, video games simulate the texture of the real world in two ways: through visual appearance or effects.
A stone cavern wall or a splintered wood floor communicates texture by appearance. Contemporary graphics processing units make the surface textures of objects in games appear lifelike, just like the wood slats in Magritte's painting.
When the player moves around in these worlds, the renderer's real-time updates reinforce the sense of texture in the scene by offering different views of the same surfaces.
The driver's shoulder or the soldier's swamp communicates texture by effect. When the player operates machines or moves creatures, their behaviors are constrained by the physical consequences certain textures represent.
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