50d7127c51
This is a number ranging between 0 and 1 based on the log of the illuminance of
the moon outside the atmosphere. It is calculated as
factor = (log(I) - max_loglux) / (max_loglux - min_loglux) + 1.0,
where I is the illuminance of the moon outside the atmosphere and min_loglux and
max_loglux are hardcoded to -0.504030345621 and -4.39964634562 respectively.
Although the value should never be outside of [0, 1], for safety it is clipped
to be between these values. For more background, see
http://forum.flightgear.org/viewtopic.php?f=47&t=28201&start=60#p270516 .
SimGear - Simulator Construction Tools ====================================== http://www.flightgear.org SimGear is a set of open-source libraries designed to be used as building blocks for quickly assembling 3d simulations, games, and visualization applications. SimGear is developed by the FlightGear project and also provides the base for the FlightGear Flight Simulator. Source code for SimGear is released under the GNU Library General Public License (LGPL) - see COPYING for license details. See INSTALL file for help on building SimGear.