The “Sky” panel controls light and color intensity influencing the entire scene (terrain, 3D models, sky, and fog). Additionally, Fog can be enabled and configured.
If the “Time of day” functionality is not activated (checkbox in the right part), the entire scene is illuminated with a white light. If active, there is a large number of lighting conditions that can be simulated.
This panel consists of three sections:
The first section, “Sky” defines the following parameters:
Background color: The sky is drawn with a single color. This is sometimes desirable in scenes without a terrain.
Sky: The sky is drawn with a complex color gradient.
The second section, “Fog” controls the fog in the scene. Fog is a subordinate to the time of day functionality, insofar as the lighting intensity also influences the fog’s color.
Type: There are various models for fog to choose from. “Linear”, “Exponential” and “Exponential squared” are simple fog models, “Advanced” is a pixel shader powered fog model that generates much better images. However, “Advanced” is only available if the graphics hardware supports pixel shader 1.4.
Fog start distance: For “Linear” fog, defines the distance at which the fog starts.
View distance: Defines the distance from the camera at which the visibility is at most 10%.
Fog color: The color of the fog.
In the third section, “Time of day” defines realistic illumination conditions. Given a date and a time, the illumination conditions will be calculated using the exact sun position:
Date: The time and date for which the lighting conditions should be calculated. The time is local standard time.
Daylight saving time: The time is interpreted as daylight saving time (“summer time”).
Acceleration: How much faster the virtual time passes than real time. A value of 2 means, that it will take 12 hours until a 24hour day is over. Note how the illumination changes over time.
Time: Sets the time of day. The play, stop and backward buttons control how the time passes.