Bloom

From GMod Wiki

Post Processing Effect

Back

Type:	Post processing effect
Notes:	Makes bright lights look brighter.

Brief

Screen-space bloom filters are the most recognizable part of what's known as HDR rendering[1], but bloom by itself is NOT HDR.

However, bloom shaders can, as in Garry's Mod, be used independently to provide a visually appealing—though technically incorrect—approximation of the "blown out" highlights that result from extremely bright light sources.

More specifically, the method of operation for an average bloom shader is as follows:

1. Isolate all portions of the scene that are above a certain brightness. This corresponds to the "darken amount" variable in GMod.
2. Blur them by a certain size. This corresponds to the "blur horizontal" and "blur vertical" variables in GMod.
3. Increase the brightness of the resulting highlights. This corresponds to the "multiply amount" variable in GMod.
4. Combine this image back into the original scene.

This can be done multiple times ("number of passes" variable in GMod) to exaggerate the effect in a smoother fashion than simply turning up the sliders, but there is a corresponding performance hit: more passes will slow your framerate.

Variables

See above. Additionally, there is a variable called "color multiplier." This increases the color saturation in the bloomed highlights.

Useful hints

• Check out the predefined presets.

Bloom Depth of Field Motion Blur Material Overlay Color Modification Morph Sharpen Sun Beams Super DoF