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

Stencil Buffer

Finally, the stencil buffer is used to restrict drawing to certain portions of the screen. Think of it like a cardboard stencil that can be used with a can of spray paint to make fairly precise painted images. For example, a classic use is to simulate the view of a rear-view mirror in a car. You render the shape of the mirror to the stencil buffer, and then draw the entire scene. The stencil buffer prevents anything that wouldn’t be visible in the mirror from being drawn. We discuss the stencil buffer in “Stencil Buffer” on Page 146.