Bump maps are a commonly used technique to map more detail (ie bumps) onto simple geometry. Bump maps do not actually change the underlying geometry, only the lighting is changed as if the geometry was more complex. Interactive techniques usually use the Blinn-Phong model for the lighting of the bumps [Bli77](local illumination only), but without shadows. Although techniques for shadowing bump maps have been developed [Max88], they are not commonly used. In particular they cannot be used for hardware rendering. We propose a novel technique which adds shadows to bump maps, but acts only as an extension to bump mapping. One can use any traditional bump mapping technique and then simply add shadows on top of that. We have implemented two slightly different methods: hard shadows and shadows with antialiased shadow boundaries 1. The antialiased shadow method could be even seen as a fake soft shadow algorithm. As we assume parallel light, it is obvious that it does not correspond to real soft shadows. We use texture mapping and frame buffer arithmetic to perform the shadow test and to write the result as a shadow mask into the stencil buffer. Then we render the bump map in a traditional way (dot product bump mapping in our case) just with the stencil test turned on so that the shadowed parts remain dark. The antialiased shadow algorithm on the other hand uses the alpha channel to modulate the intensities of the bump mapped surface. In order to be able to do all this with graphics hardware, we have developed a new way to represent shadows for all possible light directions, such that the shadow test is so simple that current graphics hardware can be used to do this test at interactive rates (assuming a directional light source).