Bloom

The Bloom effect makes bright areas in your image glow. To do this, it creates fringes of light that extend from bright areas in your image. This simulates the effect a real-world camera gives when light overwhelms the lens.

The Bloom effect also has a Dirtiness feature, which you can use to apply a full-screen layer of smudges or dust to diffract the Bloom effect.

Properties

Bloom settings:

Property	Function
Intensity	Set the strength of the Bloom filter.
Threshold	Set the level of brightness to filter out pixels under this level. This value is expressed in gamma-space.
Soft Knee	Set the gradual threshold for transitions between under/over-threshold (0 = hard threshold, 1 = soft threshold).
Clamp	Set the value for clamping pixels to control the Bloom amount. This value is expressed in gamma-space.
Diffusion	Set the extent of veiling effects in a screen resolution-independent fashion.
Anamorphic Ratio	Set the ratio to scale the Bloom vertically (in range [-1,0]) or horizontally (in range [0,1]). This emulates the effect of an anamorphic lens.
Color	Select the color of the tint of the Bloom filter.
Fast Mode	Enable this checkbox to boost performance by lowering the Bloom effect quality.

Dirtiness settings:

Property	Function
Texture	Select a Dirtiness texture to add smudges or dust to the lens.
Intensity	Set the amount of lens dirtiness.

Details

With properly exposed HDR scenes, the Threshold should be set to ~1 so that only pixels with values above 1 leak into surrounding objects. Lower this value when working in LDR or the Bloom effect won’t be visible.

Performance

Lowering the Diffusion parameter will make the effect faster. The further away Anamorphic Ratio is from 0, the slower it will be. Enable Fast Mode if you are developing for mobile or low-end platforms to get a significant boost in performance.

Lower resolution lens dirt textures result in faster lookup and blending across volumes.

Requirements

• Shader model 3