The physical basis of bloom is that, in the real world, lenses can never focus perfectly. Under normal circumstances, these imperfections are not noticeable, but an intensely bright light source will cause the imperfections to become visible. As a result, the image of the bright light appears to bleed beyond its natural borders. Bloom Lighting is a commonly used post-processing effect. It gives shiny halos of light to particularly bright parts of objects, as is seen with most camera lenses.
Bloom effect in Vanda Engine 1
The same scene without Bloom effect
