Creative use of assets in videogames

Models and textures are two of the most basic assets in a 3D game. From vast environments to collectable items, everything in a 3D game have to be carefully modeled and textured.

Shadow of the Colossus for the PS2 is a good example of how models and textures can be used to create new effects while working with hardware limitations.

Shadow of the Colossus is generally referred to as one of the games that pushed the boundaries of the PS2 in terms of graphics, and one of the reasons for that was the way it could render fur in real time, an effect almost impossible to achieve with the PS2 hardware. The fur of the colossi play an important role in the game, since it indicates the areas the player can climb. This also means that these areas had to be very detailed, since the player would see them from a close distance.

The most basic technique to simulate fur and hair in games consists in using textured planes with opacity maps in a perpendicular position to the model.

In Shadow of the Colossus the effect was achieved with a combination of perpendicular and parallel textured planes. This technique was used to keep the effect visible in every angle.

A normal mapping of the hair texture was added to the planes to add highlights and reflections to the fur of the colossi. The finishing touch was the vector unit lighting system that creates the illusion of an anisotropic effect.

Example of hair shader with anisotropic reflections

While this technique was very economic in terms of polygon count, the resulting effect was very impressive.