Bloom is another postprocessing effect commonly used with HDR which reproduces a video camera artifact. You can think of bloom as light leakage from very bright pixels to dimmer neighbouring pixels. The following images show the same scene without bloom on the left and with bloom on the right:
Bloom is tightly connected to HDR rendering as it requires the average luminance to determine which pixels are bright enough to leak into their neighbors. In addition, blooming in LDR values is very likely to saturate values which will result in an output image which looks burned.
First we need to add three new textures with a size of 1/16 ...