OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Shadow Mapping

Recent advances in computer graphics have produced a plethora of techniques for rendering realistic lighting and shadows. OpenGL can be used to implement almost any of them. In this section, we will cover one technique known as shadow mapping, which uses a depth texture to determine whether a point is lit or not.

Shadow mapping is a multipass technique that uses depth textures to provide a solution to rendering shadows. A key pass is to view the scene from the shadow-casting light source rather than from the final viewpoint. By moving the viewpoint to the position of the light source, you will notice that everything seen from that location is lit—there are no shadows from the perspective of the light. By rendering the scene’s ...