Relief Textures

We have developed a new method for transforming images with per-pixel displacements into textures that have correct parallax when texture-mapped, in the usual way, onto polygons. Our new method results from factoring the 3-D image-warping equations of McMillan and Bishop into a prewarp followed by standard texture mapping. The pre-warp handles only the parallax effects resulting from the direction of view and the displacement of texture elements; the subsequent texture-mapping operation handles scaling, rotation, and the remaining perspective transformation. The pre-warp equations have a very simple 1-D structure that enables the pre-warp to be implemented using only 1-D image operations along scan lines and columns and requires interpolation between only two adjacent pixels 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 how our relief textures can be used both to add realistic surface detail and to render complex scenes and objects.