HDRR is really cool. Basically all of the textures in your scene are floating point, with the lighting and environment added on top. As I recall, you also have a fragment shader that applies a function to each pixel to adjust the brightness (don't remember, going off of memory which is a little fuzzy lately). When all is said and done you effectively end up with a "sliding scale" glow that very effectively and realistically imitates image exposure.
The exact same results can be achieved with the bloom glow effect and older hardware, but in order to make it realistic the lighting environment can never change and you need special equipment to analyze real-world lighting conditions that look like what you want, and you need to fiddle around with the saturation of all of your textures. Basically it's more effort than it's usually worth, so games like Far Cry and Fable just take a stab in the dark.
The exact same results can be achieved with the bloom glow effect and older hardware, but in order to make it realistic the lighting environment can never change and you need special equipment to analyze real-world lighting conditions that look like what you want, and you need to fiddle around with the saturation of all of your textures. Basically it's more effort than it's usually worth, so games like Far Cry and Fable just take a stab in the dark.
Originally Posted by FastGamerr