Bloom (sometimes called glow), is a technique for simulating the effect of light bleeding around the edges of objects due to optical imperfections along the light path. A similar looking effect occurs when a bright light source illuminates nearby particles in the air, such as a street light on a foggy night.

We created a bloom effect that, while not physically accurate, provides a lot of artistic control to achieve a desired result.

Parameters

Screen Texture - this should always be a Screen Texture object

Bloom Texture - the image you want to glow. This should be either a Screen Texture or a separate render target (see Guide below). NOTE: Mipmaps MUST be on for this texture input or else Bloom won’t work correctly!

Blur Size - the radius of the blur

Brightness - the strength of the bloom

Saturation - for increasing or decreasing the saturation of the bloom

Color - a color multiplier for the bloom

Bloom Only - only output the bloom result, useful for dialing in bloom parameters or for custom user setups

Luma Mask - apply bloom based on the luminance of the Bloom Texture, creating a more realistic and responsive effect

Mask Brightness - the brightness of the luminance mask

Mask Contrast - the contrast of the luminance mask

Color Mask - apply bloom only to a given color, can be used in combination with Luma Mask

Color - the target color for the color mask

Range - the range of values to be allowed around the target color

Threshold - the sensitivity of the color mask

Guide

A powerful option for Bloom is to use your own custom render target for the Bloom Texture. This lets you completely isolate bloom to specific objects, textures, or whatever you want. In this example, I’ve rendered different objects into a separate layer and used that for the Bloom Texture. 

To start adding bloom effects to your object, make sure Bloom [PLACE_BELOW_ALL_OBJECTS_IN_HIERARCHY] object is at the bottom of your scene hierarchy in the Objects panel.

Then, duplicate the object that you want to bloom and set it as a child of the object that you duplicated from. 

Now set the layer of the new object to Bloom layer in the Inspector panel.

You can select the Bloom [EDIT_ME] material in the Resources panel to customize the bloom looks.

For more information about custom materials please visit the Material Editor guide page.