Fast shadows and lighting effects using texture mapping

Generating images of texture mapped geometry requires projecting surfaces onto a two-dimensional screen. If this projection involves perspective, then a division must be performed at each pixel of the projected surface in order to correctly calculate texture map coordinates. We show how a simple extension to perspective-correct texture mapping can be used to create various lighting effects. These include arbitrary projection of two-dimensional images onto geometry, realistic spotlights, and generation of shadows using shadow maps[10]. These effects are obtained in real time using hardware that performs correct texture mapping.