Graphics Programming: Special Effects - Lens Flare
Abstract: This article introduces a novel way in which to generate texture information from pixels already rendered to the frame buffer. The technique can be used in several different ways, but is presented here as a solution to the common problem of occluded lens flare. Many games attempt to read back pixels generated in the frame buffer in order to determine exactly what was visible in the final scene. We will present a technique that works without CPU assistance, and does not require reading data from the graphics card. We will also outline the reasons why reading back information from the graphics card can be a costly operation and should be avoided if possible.
Abstract: This article shows how to implement an attractive lens flare effect using only a small amount of code and artwork, without needing to know anything about physical optics.
Texture Masking for Faster Lens Flare