From 823510f0b4fd6c79a747c895b074e6ffd6f1b9ed Mon Sep 17 00:00:00 2001
From: Stuart Buchanan <stuart_d_buchanan@yahoo.co.uk>
Date: Tue, 16 Apr 2013 22:09:44 +0100
Subject: [PATCH] Basic Weather integration with Atmospheric Shader.

---
 Environment/local-weather-rules.xml | 708 +++++++++++++++++++++++++++-
 1 file changed, 707 insertions(+), 1 deletion(-)

diff --git a/Environment/local-weather-rules.xml b/Environment/local-weather-rules.xml
index 457a730e0..2e9b07e77 100644
--- a/Environment/local-weather-rules.xml
+++ b/Environment/local-weather-rules.xml
@@ -16,7 +16,7 @@
  General Public License for more details.
 -->
 <!--
-  Compute local weather related properties
+  Compute Atmospheric Light Shading related properties
 -->
 <PropertyList>
 
@@ -45,4 +45,710 @@
     <type>gain</type>
     <gain>0.30480</gain> 
   </filter>
+ 
+  <!-- Properties used by the atmospheric scattering shader, when not being set directly 
+       by Advanced Weather -->
+       
+  <filter>
+    <!--  Ground visibility.  Same as lowest boundary layer.  -->
+    <name>EnvironmentInterpolator:AtmosphericShader:ground-visibility-m</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <not>
+          <property>/nasal/local_weather/enabled</property>
+          <value>true</value>
+        </not>
+      </condition>
+    </enable>
+    <input>/environment/config/boundary/entry[0]/visibility-m</input>
+    <output>/environment/ground-visibility-m</output>
+  </filter>
+
+  <filter>
+    <!--  Ground haze level - assumed to be up to the lowest cloud layer.  -->
+    <name>EnvironmentInterpolator:AtmosphericShader:GroundHazeThickness</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <not>
+          <property>/nasal/local_weather/enabled</property>
+          <value>true</value>
+        </not>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <sum>
+          <property>/environment/clouds/layer[0]/elevation-ft</property>
+          <property>/environment/clouds/layer[0]/thickness-ft</property>
+        </sum>
+      </expression>
+    </input>
+    <gain>
+      <!-- feet to meters -->
+      <value>0.3048</value>
+    </gain>
+    <u_min>
+      <value>0</value>
+    </u_min>
+    <u_max>
+      <!-- haze maxes out at 6000ft.  Could probably do something using lapse rates instead -->
+      <value>2000</value>
+    </u_max> 
+    <output>/environment/ground-haze-thickness-m</output>
+  </filter>
+  
+  <!--  Build up the ground level scattering from 1 for clear skies to 0.6 for overcast -->
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:GroundScattering:0:Clear</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <equals>
+            <property>/environment/clouds/layer[0]/coverage</property>
+            <value>clear</value>
+          </equals>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <value>1</value>
+    </input>
+    <output>/environment/surface/ground-scattering</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:GroundScattering:0:Few</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <equals>
+            <property>/environment/clouds/layer[0]/coverage</property>
+            <value>few</value>
+          </equals>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <value>0.9</value>
+    </input>
+    <output>/environment/surface/ground-scattering</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:GroundScattering:0:Scattered</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <equals>
+            <property>/environment/clouds/layer[0]/coverage</property>
+            <value>scattered</value>
+          </equals>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <value>0.8</value>
+    </input>
+    <output>/environment/surface/ground-scattering</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:GroundScattering:0:Broken</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <equals>
+            <property>/environment/clouds/layer[0]/coverage</property>
+            <value>broken</value>
+          </equals>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <value>0.7</value>
+    </input>
+    <output>/environment/surface/ground-scattering</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:GroundScattering:0:Overcast</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <equals>
+            <property>/environment/clouds/layer[0]/coverage</property>
+            <value>overcast</value>
+          </equals>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <value>0.6</value>
+    </input>
+    <output>/environment/surface/ground-scattering</output>
+  </filter>
+  
+  <!-- TODO: Handle layers beyond the first -->
+  
+  <!-- Set the scattering at the aircraft level -->
+
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Scattering:AircraftAboveLayer</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <greater-than>
+            <property>/position/altitude-ft</property>
+            <expression>
+              <sum>
+                <property>/environment/clouds/layer[0]/elevation-ft</property>
+                <property>/environment/clouds/layer[0]/thickness-ft</property>
+              </sum>
+            </expression>
+          </greater-than>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <value>1</value>
+    </input>
+    <output>/rendering/scene/scattering</output>
+  </filter>
+
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Scattering:AircraftBelowLayer</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <less-than-equals>
+            <property>/position/altitude-ft</property>
+            <expression>
+              <sum>
+                <property>/environment/clouds/layer[0]/elevation-ft</property>
+                <property>/environment/clouds/layer[0]/thickness-ft</property>
+              </sum>
+            </expression>
+          </less-than-equals>
+        </and>
+      </condition>
+    </enable>
+    <input>/environment/surface/ground-scattering</input>
+    <output>/rendering/scene/scattering</output>
+  </filter>
+  
+  <!-- Clouds self-shading -->
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:CloudSelfShading</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <not>
+          <property>/nasal/local_weather/enabled</property>
+          <value>true</value>
+        </not>
+      </condition>
+    </enable>
+    <input>
+      <!-- TODO : Make this sun-angle dependent -->
+      <value>1.0</value>    
+    </input>
+    <output>/environment/cloud-self-shading</output>
+  </filter>
+  
+  <!-- Skydome parameters - /sim/rendering/[mie|rayleigh|dome-density] -->
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:VisFactor</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <not>
+          <property>/nasal/local_weather/enabled</property>
+          <value>true</value>
+        </not>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <product>    
+          <difference> 
+            <property>/environment/visibility-m</property>
+            <value>30000</value>
+          </difference>
+          <value>0.000011111</value>
+        </product>
+      </expression>
+    </input>
+    <u_min>0.0</u_min>
+    <u_max>1.0</u_max>
+    <output>/sim/rendering/skydome-vis-factor</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Rayleigh:Low</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <less-than>
+            <property>/position/altitude-ft</property>
+            <value>36000</value>
+          </less-than>          
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+         <difference>
+           <value>0.0003</value>
+           <product>
+             <property>/sim/rendering/skydome-vis-factor</property>
+             <value>0.0001</value>
+           </product>
+         </difference>
+      </expression>
+    </input>
+    <output>/sim/rendering/rayleigh-no-polution</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Rayleigh:Medium</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <greater-than>
+            <property>/position/altitude-ft</property>
+            <value>36000</value>
+          </greater-than>          
+          <less-than>
+            <property>/position/altitude-ft</property>
+            <value>85000</value>
+          </less-than>          
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <difference>
+          <difference>
+            <value>0.0003</value>
+            <product>
+              <property>/sim/rendering/skydome-vis-factor</property>
+              <value>0.0001</value>
+            </product>
+          </difference>
+          <product>
+            <difference>
+              <property>/position/altitude-ft</property>
+              <value>36000</value>
+            </difference>
+            <value>0.000000002</value>
+          </product>
+        </difference>
+      </expression>
+    </input>
+    <output>/sim/rendering/rayleigh-no-polution</output>
+  </filter>
+
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Rayleigh:High</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <greater-than>
+            <property>/position/altitude-ft</property>
+            <value>85000</value>
+          </greater-than>          
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+         <difference>
+           <value>0.0002</value>
+           <product>
+             <property>/sim/rendering/skydome-vis-factor</property>
+             <value>0.0001</value>
+           </product>
+         </difference>
+      </expression>
+    </input>
+    <output>/sim/rendering/rayleigh-no-polution</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Rayleight:Polution:Low</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <less-than-equals>
+            <property>/position/altitude-ft</property>
+            <expression>
+              <sum>
+                <property>/environment/clouds/layer[0]/elevation-ft</property>
+                <property>/environment/clouds/layer[0]/thickness-ft</property>
+              </sum>
+            </expression>
+          </less-than-equals>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <sum>
+          <property>/sim/rendering/rayleigh-no-polution</property>
+          <product>
+            <property>/environment/air-pollution-norm</property>
+            <value>0.0003</value>
+          </product>
+          <product>
+            <property>/environment/air-pollution-norm</property>
+            <value>0.0004</value>
+            <difference>
+              <value>1.0</value>
+              <product>
+                <div>
+                  <property>/position/altitude-ft</property>
+                  <sum>
+                    <property>/environment/clouds/layer[0]/elevation-ft</property>
+                    <property>/environment/clouds/layer[0]/thickness-ft</property>
+                    <value>1.0</value><!-- to avoid divide by 0 exceptions -->
+                  </sum>
+                </div>
+                <div>
+                  <property>/position/altitude-ft</property>
+                  <sum>
+                    <property>/environment/clouds/layer[0]/elevation-ft</property>
+                    <property>/environment/clouds/layer[0]/thickness-ft</property>
+                    <value>1.0</value><!-- to avoid divide by 0 exceptions -->
+                  </sum>
+                </div>
+              </product>
+            </difference>
+          </product>
+        </sum>
+      </expression>
+    </input>
+    <output>/sim/rendering/rayleigh</output>
+  </filter>
+
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Rayleight:Polution:High</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <greater-than>
+            <property>/position/altitude-ft</property>
+            <expression>
+              <sum>
+                <property>/environment/clouds/layer[0]/elevation-ft</property>
+                <property>/environment/clouds/layer[0]/thickness-ft</property>
+              </sum>
+            </expression>
+          </greater-than>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <sum>
+          <property>/sim/rendering/rayleigh-no-polution</property>
+          <product>
+            <property>/environment/air-pollution-norm</property>
+            <value>0.0003</value>
+          </product>
+        </sum>
+      </expression>
+    </input>
+    <output>/sim/rendering/rayleigh</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Mie:Low</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <less-than>
+            <property>/position/altitude-ft</property>
+            <value>36000</value>
+          </less-than>          
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+         <difference>
+           <value>0.005</value>
+           <product>
+             <property>/sim/rendering/skydome-vis-factor</property>
+             <value>0.002</value>
+          </product>
+        </difference>
+      </expression>
+    </input>
+    <output>/sim/rendering/mie</output>
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Mie:Medium</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <greater-than>
+            <property>/position/altitude-ft</property>
+            <value>36000</value>
+          </greater-than>          
+          <less-than>
+            <property>/position/altitude-ft</property>
+            <value>85000</value>
+          </less-than>          
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <difference>
+           <difference>
+             <value>0.005</value>
+             <product>
+               <property>/sim/rendering/skydome-vis-factor</property>
+               <value>0.002</value>
+            </product>
+          </difference>
+          <product>
+            <difference>
+              <property>/position/altitude-ft</property>
+              <value>36000</value>
+            </difference>
+            <value>0.00000004</value>
+          </product>
+        </difference>
+      </expression>
+    </input>
+    <output>/sim/rendering/mie</output>
+  </filter>         
+
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Mie:High</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <greater-than>
+            <property>/position/altitude-ft</property>
+            <value>85000</value>
+          </greater-than>          
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+         <difference>
+           <value>0.003</value>
+           <product>
+             <property>/sim/rendering/skydome-vis-factor</property>
+             <value>0.002</value>
+          </product>
+        </difference>
+      </expression>
+    </input>
+    <output>/sim/rendering/mie</output>
+  </filter>
+  
+  <!-- Density -->
+
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Density:Low</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <less-than-equals>
+            <property>/position/altitude-ft</property>
+            <expression>
+              <sum>
+                <property>/environment/clouds/layer[0]/elevation-ft</property>
+                <property>/environment/clouds/layer[0]/thickness-ft</property>
+              </sum>
+            </expression>
+          </less-than-equals>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <sum>
+          <value>0.3</value>
+          <product>
+            <property>/environment/air-pollution-norm</property>
+            <value>0.05</value>
+          </product>
+          <product>
+            <property>/environment/air-pollution-norm</property>
+            <value>0.05</value>
+            <difference>
+              <value>1.0</value>
+              <product>
+                <div>
+                  <property>/position/altitude-ft</property>
+                  <sum>
+                    <property>/environment/clouds/layer[0]/elevation-ft</property>
+                    <property>/environment/clouds/layer[0]/thickness-ft</property>
+                    <value>1.0</value><!-- to avoid divide by 0 exceptions -->
+                  </sum>
+                </div>
+                <div>
+                  <property>/position/altitude-ft</property>
+                  <sum>
+                    <property>/environment/clouds/layer[0]/elevation-ft</property>
+                    <property>/environment/clouds/layer[0]/thickness-ft</property>
+                    <value>1.0</value><!-- to avoid divide by 0 exceptions -->
+                  </sum>
+                </div>
+              </product>
+            </difference>
+          </product>
+        </sum>
+      </expression>
+    </input>
+    <output>/sim/rendering/dome-density</output>
+  </filter>
+
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:Density:High</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <and>
+          <not>
+            <property>/nasal/local_weather/enabled</property>
+            <value>true</value>
+          </not>
+          <greater-than>
+            <property>/position/altitude-ft</property>
+            <expression>
+              <sum>
+                <property>/environment/clouds/layer[0]/elevation-ft</property>
+                <property>/environment/clouds/layer[0]/thickness-ft</property>
+              </sum>
+            </expression>
+          </greater-than>
+        </and>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <sum>
+          <value>0.3</value>
+          <product>
+            <property>/environment/air-pollution-norm</property>
+            <value>0.05</value>
+          </product>
+        </sum>
+      </expression>
+    </input>
+    <output>/sim/rendering/dome-density</output>
+  </filter>
+  
+  <!-- Mean elevation. No easy way to do this, so we'll just use the altitude of the nearest METAR station -->
+  <filter>
+    <name>EnvironmentInterpolator:AtmosphericShader:Skydome:MeanElevation</name>
+    <type>gain</type>
+    <enable>
+      <condition>
+        <not>
+          <property>/nasal/local_weather/enabled</property>
+          <value>true</value>
+        </not>
+      </condition>
+    </enable>
+    <input>
+      <expression>
+        <product>
+          <property>/environment/metar[0]/station-elevation-ft</property>
+          <value>0.3048</value>
+        </product>
+      </expression>
+    </input>
+    <output>/environment/mean-terrain-elevation-m</output>
+  </filter>
+  
 </PropertyList>