From 32ff0056ef063480e880e37907b41705323e41ac Mon Sep 17 00:00:00 2001
From: Thorsten Renk <thorsten@science-and-fiction.org>
Date: Fri, 9 Jun 2017 12:07:51 +0300
Subject: [PATCH] Daily variation of road traffic with commuter rush hours
 based on actual traffic studies for ALS road shader

---
 Effects/road.eff                    |   9 +++
 Environment/local-weather-rules.xml | 101 ++++++++++++++++++++++++++++
 Shaders/road-ALS-ultra.frag         |   3 +-
 3 files changed, 112 insertions(+), 1 deletion(-)

diff --git a/Effects/road.eff b/Effects/road.eff
index 1ddf88dff..be53d4f11 100644
--- a/Effects/road.eff
+++ b/Effects/road.eff
@@ -23,6 +23,7 @@
 	<road-traffic-enabled><use>/sim/rendering/osm/road-traffic-enabled</use></road-traffic-enabled>
 	<road-traffic-density><use>/sim/rendering/osm/road-traffic-density</use></road-traffic-density>
 	<road-traffic-direction><use>/sim/rendering/osm/road-traffic-direction</use></road-traffic-direction>
+	<road-traffic-variation><use>/sim/rendering/osm/road-traffic-daily-variation</use></road-traffic-variation>
 	<road-light-factor><use>/environment/lightmap-factor</use></road-light-factor>
   </parameters>
 
@@ -488,6 +489,14 @@
 				   </value>
 			   </uniform>
 
+			   <uniform>
+				   <name>road_traffic_variation</name>
+				   <type>float</type>
+				   <value>
+					   <use>road-traffic-variation</use>
+				   </value>
+			   </uniform>
+
 			   <uniform>
 				   <name>road_traffic_direction</name>
 				   <type>int</type>
diff --git a/Environment/local-weather-rules.xml b/Environment/local-weather-rules.xml
index 4313bb746..1206cbca6 100644
--- a/Environment/local-weather-rules.xml
+++ b/Environment/local-weather-rules.xml
@@ -839,7 +839,108 @@
     <output>/environment/lightmap-factor</output>
   </filter>
 
+<!-- Daily variation of road traffic for the road shader -->
 
+	
+  <filter>
+    <name>EnvironmentInterpolator:OSM:LocalTime</name>
+    <input>
+	 <expression>
+	  <sum>
+        <property>/sim/time/utc/day-seconds</property>
+		<property>/sim/time/local-offset</property>
+	  </sum>
+	 </expression>
+    </input>
+    <output>/sim/time/local-day-seconds</output>
+    <type>gain</type>
+    <gain>1.0</gain> 
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:OSM:LocalTimeOverrun</name>
+	<enable>
+      <condition>
+	    <greater-than>
+	    <property>/sim/time/local-day-seconds</property>
+		<value>86400.0</value>
+		</greater-than>
+      </condition>
+    </enable>
+    <input>
+	 <expression>
+	  <difference>
+        <property>/sim/time/local-day-seconds</property>
+		<value>86400</value>
+	  </difference>
+	 </expression>
+    </input>
+    <output>/sim/time/local-day-seconds</output>
+    <type>gain</type>
+    <gain>1.0</gain> 
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:OSM:LocalTimeUnderrun</name>
+	<enable>
+      <condition>
+	    <less-than>
+	    <property>/sim/time/local-day-seconds</property>
+		<value>0.0</value>
+		</less-than>
+      </condition>
+    </enable>
+    <input>
+	 <expression>
+	  <sum>
+        <property>/sim/time/local-day-seconds</property>
+		<value>86400</value>
+	  </sum>
+	 </expression>
+    </input>
+    <output>/sim/time/local-day-seconds</output>
+    <type>gain</type>
+    <gain>1.0</gain> 
+  </filter>
+  
+  <filter>
+    <name>EnvironmentInterpolator:OSM:TrafficDensity</name>
+	<type>gain</type>
+    <input>
+	<expression>
+      <table>
+        <property>/sim/time/local-day-seconds</property>
+        <entry><ind>0.0</ind><dep>0.32</dep></entry>
+        <entry><ind>3600.0</ind><dep>0.21</dep></entry>
+		<entry><ind>7200.0</ind><dep>0.18</dep></entry>
+		<entry><ind>10800.0</ind><dep>0.16</dep></entry>
+		<entry><ind>14400.0</ind><dep>0.19</dep></entry>
+		<entry><ind>18000.0</ind><dep>0.21</dep></entry>
+		<entry><ind>21600.0</ind><dep>0.45</dep></entry>
+		<entry><ind>25200.0</ind><dep>0.77</dep></entry>
+		<entry><ind>28800.0</ind><dep>1.30</dep></entry>
+		<entry><ind>32400.0</ind><dep>1.44</dep></entry>
+		<entry><ind>36000.0</ind><dep>1.04</dep></entry>
+		<entry><ind>39600.0</ind><dep>0.95</dep></entry>
+		<entry><ind>43200.0</ind><dep>1.03</dep></entry>
+		<entry><ind>46800.0</ind><dep>1.04</dep></entry>
+		<entry><ind>50400.0</ind><dep>1.10</dep></entry>
+		<entry><ind>54000.0</ind><dep>1.30</dep></entry>
+		<entry><ind>57600.0</ind><dep>1.50</dep></entry>
+		<entry><ind>61200.0</ind><dep>1.26</dep></entry>
+		<entry><ind>64800.0</ind><dep>0.92</dep></entry>
+		<entry><ind>68400.0</ind><dep>0.72</dep></entry>
+		<entry><ind>72000.0</ind><dep>0.56</dep></entry>
+		<entry><ind>75600.0</ind><dep>0.52</dep></entry>
+		<entry><ind>79200.0</ind><dep>0.45</dep></entry>
+		<entry><ind>82800.0</ind><dep>0.36</dep></entry>
+      </table>	
+	</expression>
+    </input>
+    <output>/sim/rendering/osm/road-traffic-daily-variation</output>
+  </filter>
+
+<!-- illumination setting for precipitation particles -->
 
   <filter>
     <name>EnvironmentInterpolator:Precipitation:Illumination</name>
diff --git a/Shaders/road-ALS-ultra.frag b/Shaders/road-ALS-ultra.frag
index ab06a9fc6..02e82da5c 100644
--- a/Shaders/road-ALS-ultra.frag
+++ b/Shaders/road-ALS-ultra.frag
@@ -57,6 +57,7 @@ uniform float grain_magnification;
 uniform float wetness;
 uniform float rain_norm;
 uniform float road_traffic_density;
+uniform float road_traffic_variation;
 uniform float streetlight_factor;
 
 uniform float avisibility;
@@ -353,7 +354,7 @@ void main (void)
 
 		cSign *= road_traffic_direction;
 
-		float total_traffic_density = road_traffic_density * rtype_traffic_density;
+		float total_traffic_density = road_traffic_density * rtype_traffic_density * road_traffic_variation;
 
 		float cCoord = roadCoords.t + cOffset;
 		cCoord += 0.3 * osg_SimulationTime * cSign * rtype_traffic_speed * (1.0 - (0.9 * smoothstep(1.0, 2.5, total_traffic_density)));