[Flightgear-devel] Unexpected behaviour of FlightGear's "material" animation

[Greg H. <gr...@on...>]

Hi all,

I have created some FlightGear scenery models that light up at night.  I 
have followed the directions contained on the "Howto: Illuminate faces" 
page on the FlightGear wiki. My model's XML file contains the following:

<animation>
<type>material</type>
<object-name>Walls</object-name>
<condition>
<greater-than>
<property>/sim/time/sun-angle-rad</property>
<value>1.70170</value>
</greater-than>
</condition>
<emission>
<red>1</red>
<green>1</green>
<blue>1</blue>
</emission>
</animation>

Using FlightGear 1.9.1 on Ubuntu 10.04, this works -- except the lights 
don't turn off.  The wiki says that the lights will turn off 
automatically when the condition is no longer true, but this did not 
work for me. To turn the lights off I needed to include the following:

<animation>
<type>material</type>
<object-name>Walls</object-name>
<condition>
<not>
<greater-than>
<property>/sim/time/sun-angle-rad</property>
<value>1.70170</value>
</greater-than>
</not>
</condition>
<emission>
<red>0</red>
<green>0</green>
<blue>0</blue>
</emission>
</animation>

Can anyone confirm whether the behaviour works as described in the wiki? 
Should the lights automatically turn off, or is the wiki wrong and the 
second condition is required?

Also, using FlightGear v2.0.0 on Ubuntu 10.04 (compiled on 1-Nov-2010 
using the "Download and Install" script), the behaviour is different 
again: the lights are lit at all times.  Has the behaviour changed for 
this version, is it still under development, or have I missed a change 
in the animation properties?

Many thanks,
Greg Hawkes