aDuDv

An aDuDv map, short for animated DuDv map, is a texture used in real-time rendering to distort texture coordinates and produce animated water effects such as ripples, refraction, and reflections. The DuDv component refers to the displacement of texture coordinates in the U and V directions; in an aDuDv map these displacements are stored in the red and green channels, respectively. The blue channel is usually unused or used for a secondary purpose in some pipelines.

In practice, a shader samples the aDuDv map using the current UV coordinates, then adds the sampled offsets (often scaled by a time-based factor) to the UVs before sampling other textures such as a reflection cube map, a refraction texture, or the water surface's normal map. The result is a moving distortion effect that simulates light bending and wind-driven surface movement.

Creation and usage: aDuDv maps are typically tileable textures authored in image editors or generated procedurally; they are designed to tile across the surface and be animated by time input. It is common to pair an aDuDv map with a normal map to control lighting and with a reflection/refraction texture to simulate water.

Limitations: the effect depends on the quality of the distortion vector and can introduce artifacts at scene boundaries; care must be taken with UV wrapping, sampling order, and performance on constrained devices.

See also: normal maps, reflection and refraction in shaders, DuDv maps.