How to do good bloom for HDR rendering

One thing that makes HDR rendering impressive is the bloom effect. In fact even if bloom is in a sense decoupled from HDR rendering, it is often confused with HDR. There are 3d engines out there that advertise bloom for HDR rendering, which is nonsense. You can have HDR rendering without bloom, and you can have bloom without HDR rendering. What makes the sweet, sweeter is the combination of the two. Actually if you present the average gamer HDR rendering without bloom, it will be hard for her to understand the difference between LDR and HDR rendering…

This means that you are going to need good blooming in your engine to really have that “WOW” thing coming out of peoples mouths. Before writing the Sylphis3D HDR rendering implementation I had read some articles about blooming but the results were never satisfactory. I’m going to present you here the method I used and that really makes a perfect bloom that is also faster to perform and uses less memory. Continue reading