Note 1/10/2012: If one uses an IDE such as Code::Blocks (www.codeblocks.org), SHAPEFS should be mostly platform independent, much like GIMP itself. Sincere apologies to any users attempting to use this plug-in. Life intervened between the time I created this and today. I'll take your advise and insure that any future versions come with the correct configure scripts as with other Linux source packages. In retrospect, I developed this at Colorado State University years ago, at a time when Windows was the only thing available.
Significantly out of date, this plug-in has been the back burner. Image examples are available at http://happycattech.com/book/graphics-applications-0 and http://alreaud.net/content/petaled-crater-mars-terra-sirenum
Shape from shading algorithms have been around for a while. Dr. Mark J. Carlotto describes a simplified version using basic trigonometry (Sculptor's Photoclinometry page in the Pacific-Sierra Research Image Shape from Shading section). In that section, Dr. Carlotto describes the Berthold Klaus Paul Horn algorithm for generating shape from shading, first described by Horn in 1989.
This plug-in generates a 3D image or movie from a gray scale source image based on the shading of the image, the sun azimuth, the camera angle (called phase angle), and the pixel size. Originally designed to be used with Mars Orbiter Camera (MOC) images, the user should be familiar with Mars Orbiter Camera ancillary parameters. The plug-in should work with any planetary data system or terrestrial image provided that the above parameters are available.
The results of this plug-in have been somewhat ground-truthed using an ISS image of the Giza pyramids. However, due to the inability to ascertain or enter albedo values for the surface in question, the results should be accepted with CAUTION.
The plug-in is very resource intensive, and requires maximal memory to function effectively on large (1000x1000) images. The author recommends a minimum of 512MB of system memory.