Manuel M. Oliveira

Relief Texture Mapping

(Under the Supervision of Gary Bishop)

We present an extension to texture mapping that supports the representation of 3-D surface details and view motion parallax. The results are correct for viewpoints that are static or moving, far away or nearby. In this approach, a relief texture (texture extended with an orthogonal displacement per texel) is mapped onto a polygon using a two-step process. First, it is converted into an ordinary texture using a surprisingly simple 1-D forward transform. The resulting texture is then mapped onto the polygon using standard texture mapping. The 1-D warping functions work in texture coordinates to handle the parallax and visibility changes that result from the 3-D shape of the displacement surface. The subsequent texture-mapping operation handles the transformation from texture to screen coordinates.

The pre-warping equations have a very simple 1-D structure that enables the pre- warp to be implemented using only 1-D image operations along rows and columns and requires interpolation between only two adjacent texels at a time. This allows efficient implementation in software and should allow a simple and efficient hardware implementation. The texture-mapping hardware already very common in graphics systems efficiently implements the final texture mapping stage of the warp.

We demonstrate a software implementation of the method and show that it significantly increases the expressive power of conventional texture mapping. It also dramatically reduces the polygonal count required to model a scene, while preserving its realistic look. This new approach supports the representation and rendering of three- dimensional objects and immersive environments, and naturally integrates itself with popular graphics APIs. An important aspect of this research is to provide a framework for combining the photo-realistic promise of image- based modeling and rendering techniques with the advantages of polygonal rendering.