Adding Fog

Motivation

Fog increases realism:

• Add fog outside to create hazy worlds
• Add fog inside to create dark dungeons
• Use fog to set a mood

The further the viewer can see, the more you have to model and draw. To reduce development time and drawing time, limit the viewer’s sight by using fog.

Using fog visibility controls

The fog type selects linear or exponential visibility reduction with distance:

• Linear is easier to control
• Exponential is more realistic and »thicker«

The visibility range selects the distance where the fog reaches maximum thickness:

• Fog is »clear« at the viewer, and gradually reduces visibility

Selecting a fog color

• Fog has a fog color
  • White is typical, but black, red, etc. also possible
• Shapes are faded to the fog color with distance
• The background is unaffected
  • For the best effect, make the background the fog color

Syntax: Fog

A Fog node creates colored fog

• color - fog color
• fogType - LINEAR or EXPONENTIAL
• visibilityRange - maximum visibility limit

XML Encoding

<Fog
    color='1.0 1.0 1.0'
    fogType='LINEAR'
    visibilityRange='10.0'/>

Classic Encoding

Fog {
  color 1.0 1.0 1.0
  fogType "LINEAR"
  visibilityRange 10.0
}

Summary

• Fog has a color, a type, and a visibility range
• Fog can be used to set a mood, even indoors

Fog limits the viewer’s sight:

• Reduces the amount of the world you have to build
• Reduces the amount of the world that must be drawn