depthcue option = value [, option = value, ...]
An option for depth cueing. See table below.
A value associated with the matching option . See table below.
Depth cueing fades objects into the background more if they are farther from the viewer. This enables objects closer to the viewer to be seen with more clarity, to hide distractions of objects farther away, and to give an impression of depth.
Depth cueing is disabled by default, but you can enable it by passing fast or nice as the type. fast looks good enough for most purposes, but nice is recommended for speed when using the software renderer on very complex datasets.
You can control both the style and degree of depth cueing by the equation and its parameters. The following equations determine the clarity of the object based on its distance from the viewer (z):
In the following diagram, the vertical axis represents the clarity of the drawn objects, and the horizontal axis represents distance from the viewer (0=closer). The dashed line represents the linear function, the solid line represents the exp function, and the dotted line shows the exp2 function:
Using the linear equation and its start and end parameters, the depth cueing can be finely controlled. For a smoother look and simpler control, use either of the exponential equations, controlling the amount of cueing by the fade parameter. The exp2 equation gives a steeper, sigmoid-like slope and is the default equation.
depthcue type=fast # enable depth cueing
depthcue equation=linear start=0.5 end=0.501
# sharply cut off everything halfway
depthcue equation=exp fade=1.5