Adding Volumetric Fog
After adding variable rate shading in the previous chapter, we will implement another modern technique that will enhance the visuals of the Raptor Engine: Volumetric Fog. Volumetric rendering and fog are very old topics in rendering literature, but until a few years ago, they were considered impossible for real-time usage.
The possibility of making this technique feasible in real-time stems from the observation that fog is a low-frequency effect; thus the rendering can be at a much lower resolution than the screen, increasing the performance in real-time usage.
Also, the introduction of compute shaders, and thus generic GPU programming, paired with clever observations about approximations and optimizations of the volumetric aspect of the technique, paved the way to unlocking real-time Volumetric Fog.
The main idea comes from the seminal paper by Bart Wronski (https://bartwronski.files.wordpress.com/2014/08/bwronski_volumetric_fog_siggraph2014.pdf) at...
