More work on rendering lighting in ALS, public domain NOAA image resources are gratefully acknowledged

Effects/lightning.eff

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- lightning -->
+<PropertyList>
+  <name>Effects/lightning</name>
+  <inherits-from>Effects/rain-layer</inherits-from>
+  <parameters> 
+    <is-lightning type="bool">1</is-lightning>
+  </parameters>
+</PropertyList>

Effects/rain-layer.eff

@@ -11,6 +11,7 @@
     <lightning-pos-x><use>/environment/lightning/lightning-pos-x</use></lightning-pos-x>
     <lightning-pos-y><use>/environment/lightning/lightning-pos-y</use></lightning-pos-y>
     <lightning-range><use>/environment/lightning/lightning-range</use></lightning-range>
+    <is-lightning type="bool">0</is-lightning>
   </parameters>
 <technique n="9">
     <predicate>
@@ -101,6 +102,11 @@
         <type>float</type>
         <value><use>lightning-range</use></value>
       </uniform>
+      <uniform>
+        <name>is_lightning</name>
+        <type>bool</type>
+        <value><use>is-lightning</use></value>
+      </uniform>
       <!--<vertex-program-two-side>true</vertex-program-two-side>-->
     </pass>
   </technique>

Environment/local-weather-defaults.xml

@@ -108,6 +108,10 @@
     <cloud-shadow-flag type="bool" userarchive="y">0</cloud-shadow-flag>
     <cloud-shadow-fov-flag type="bool" userarchive="y">0</cloud-shadow-fov-flag>
 </cloud-shadows>
+
+ <lightning>
+    <model-index type="int" userarchive="n">0</model-index>
+ </lightning>
 </PropertyList>
 
 

Models/Weather/lightning.xml

@@ -0,0 +1,61 @@
+<?xml version="1.0"?>
+
+<PropertyList>
+
+ <path>lightning.ac</path>
+  <offsets>
+      	 <x-m> 0.0 </x-m>
+       	 <y-m> 0.0</y-m>
+       	 <z-m>-1.2 </z-m>
+   </offsets>
+
+ 
+  <effect>
+		<object-name>rect</object-name>
+		<inherits-from>Effects/lightning</inherits-from>
+  </effect>
+
+
+  <animation>
+  		<type>scale</type>
+  		<x-offset>700.0</x-offset>
+  		<y-offset>700.0</y-offset>
+ 		<z-offset>1000.0</z-offset>
+  </animation>
+
+  <animation>
+    	<type>material</type>
+   	<emission>
+      		<red>   0.9 </red>
+      		<green> 0.9 </green>
+		<blue>  1.0 </blue>
+    	</emission>
+  </animation>
+
+ <animation>
+  <type>select</type>
+  <condition>
+   <and>
+   <greater-than>
+    <property>/environment/lightning/flash</property>
+    <value>0.0</value>
+   </greater-than>
+   <equals>
+     <property>/local-weather/lightning/model-index</property>
+     <value>0</value>
+   </equals>
+  </and>
+  </condition>
+ </animation>
+
+<animation>
+  <type>billboard</type>
+  <spherical>false</spherical>
+</animation>
+ 
+<animation>
+  <enable-hot type="bool">false</enable-hot>
+</animation>
+
+
+</PropertyList>

Models/Weather/lightning1.ac

@@ -0,0 +1,22 @@
+AC3Db
+MATERIAL "ac3dmat1" rgb 1 1 1  amb 0.2 0.2 0.2  emis 0 0 0  spec 0.502 0.502 0.502  shi 10  trans 0.008
+OBJECT world
+kids 1
+OBJECT poly
+name "rect"
+loc 0.015 0.165 0
+texture "lightning01.rgb"
+numvert 4
+-0.68 1.21 0
+0.68 1.21 0
+0.68 -1.21 0
+-0.68 -1.21 0
+numsurf 1
+SURF 0x0
+mat 0
+refs 4
+3 0 0
+2 1 0
+1 1 1
+0 0 1
+kids 0

Models/Weather/lightning1.xml

@@ -1,19 +1,19 @@
 <?xml version="1.0"?>
 
 <PropertyList>
- <path>lightning.ac</path>
+ <path>lightning1.ac</path>
+  	<offsets>
+      	 	<x-m> 0.00 </x-m>
+       		<y-m> 0.01</y-m>
+       		<z-m>-1.20 </z-m>
+    	</offsets>
+
  
 	<effect>
 		<object-name>rect</object-name>
-		<inherits-from>Effects/rain-layer</inherits-from>
+		<inherits-from>Effects/lightning</inherits-from>
 	</effect>
 
-  	<offsets>
-      	 	<x-m> 0.0 </x-m>
-       		<y-m> 0.0</y-m>
-       		<z-m>-1.2 </z-m>
-    	</offsets>
-
 
   <animation>
   		<type>scale</type>
@@ -34,10 +34,16 @@
  <animation>
   <type>select</type>
   <condition>
+   <and>
    <greater-than>
     <property>/environment/lightning/flash</property>
     <value>0.0</value>
    </greater-than>
+   <equals>
+     <property>/local-weather/lightning/model-index</property>
+     <value>1</value>
+   </equals>
+  </and>
   </condition>
  </animation>
 

Models/Weather/lightning2.ac

@@ -0,0 +1,22 @@
+AC3Db
+MATERIAL "ac3dmat1" rgb 1 1 1  amb 0.2 0.2 0.2  emis 0 0 0  spec 0.502 0.502 0.502  shi 10  trans 0.008
+OBJECT world
+kids 1
+OBJECT poly
+name "rect"
+loc 0.015 0.165 0
+texture "lightning02.rgb"
+numvert 4
+-0.68 1.21 0
+0.68 1.21 0
+0.68 -1.21 0
+-0.68 -1.21 0
+numsurf 1
+SURF 0x0
+mat 0
+refs 4
+3 0 0
+2 1 0
+1 1 1
+0 0 1
+kids 0

Models/Weather/lightning2.xml

@@ -0,0 +1,60 @@
+<?xml version="1.0"?>
+
+<PropertyList>
+ <path>lightning2.ac</path>
+  	<offsets>
+      	 	<x-m> 0.00 </x-m>
+       		<y-m> 0.02 </y-m>
+       		<z-m>-1.20 </z-m>
+    	</offsets>
+
+ 
+	<effect>
+		<object-name>rect</object-name>
+		<inherits-from>Effects/lightning</inherits-from>
+	</effect>
+
+
+  <animation>
+  		<type>scale</type>
+  		<x-offset>700.0</x-offset>
+  		<y-offset>700.0</y-offset>
+ 		<z-offset>1000.0</z-offset>
+  </animation>
+
+  <animation>
+    	<type>material</type>
+   	<emission>
+      		<red>   0.9 </red>
+      		<green> 0.9 </green>
+		<blue>  1.0 </blue>
+    	</emission>
+  </animation>
+
+ <animation>
+  <type>select</type>
+  <condition>
+   <and>
+   <greater-than>
+    <property>/environment/lightning/flash</property>
+    <value>0.0</value>
+   </greater-than>
+   <equals>
+     <property>/local-weather/lightning/model-index</property>
+     <value>2</value>
+   </equals>
+  </and>
+  </condition>
+ </animation>
+
+<animation>
+  <type>billboard</type>
+  <spherical>false</spherical>
+</animation>
+ 
+<animation>
+  <enable-hot type="bool">false</enable-hot>
+</animation>
+
+
+</PropertyList>

Models/Weather/lightning_combined.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+
+<PropertyList>
+
+<model>
+ <path>lightning.xml</path>
+</model>
+
+<model>
+ <path>lightning1.xml</path>
+</model>
+
+<model>
+ <path>lightning2.xml</path>
+</model>
+
+</PropertyList>

Nasal/local_weather/local_weather.nas

@@ -4058,7 +4058,7 @@ if (local_weather.cloud_shadow_flag == 1)
 
 setprop(lw~"thunderstorm-loop-flag",1);
 
-local_weather.place_model_controlled("lightning", "Models/Weather/lightning1.xml", lat, lon, 0.0, 0.0, 0.0, 0.0);
+local_weather.place_model_controlled("lightning", "Models/Weather/lightning_combined.xml", lat, lon, 0.0, 0.0, 0.0, 0.0);
 
 local_weather.thunderstorm_management_loop();
 

Nasal/local_weather/weather_tile_management.nas

@@ -1303,6 +1303,13 @@ for (var i = 0; i < n; i=i+1)
 		setprop("/local-weather/lightning/latitude-deg", tstorm.lat - offset_x * local_weather.m_to_lat);
 		setprop("/local-weather/lightning/longitude-deg", tstorm.lon + offset_y * local_weather.m_to_lon);
 		setprop("/local-weather/lightning/altitude-ft", tstorm.alt);
+
+		var rn = rand();
+		var type = 0;
+		if (rn > 0.7) {type = 1;}
+		else if (rn > 0.3) {type = 2;}
+		setprop("/local-weather/lightning/model-index", type);	
+
 		lightning_strike();
 
 		if (dist > 50000.0)

Shaders/rain-layer-ALS.frag

@@ -1,12 +1,16 @@
 uniform sampler2D baseTexture;
 varying float fogFactor;
-
 varying vec3 hazeColor;
 
+uniform bool is_lightning;
+
 void main(void)
 {
       vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);
       vec4 finalColor = base * gl_Color;
-      gl_FragColor.rgb = mix(hazeColor, finalColor.rgb, fogFactor );
+      if (is_lightning==0)
+      	{gl_FragColor.rgb = mix(hazeColor, finalColor.rgb, fogFactor );}
+      else 
+	{gl_FragColor.rgb = finalColor;}
       gl_FragColor.a = mix(0.0, finalColor.a, fogFactor);
 }

Shaders/rain-layer-ALS.vert

@@ -101,7 +101,9 @@ void main(void)
   vec2 lightningRelVector = relVector.xy - vec2(lightning_pos_x, lightning_pos_y);
   float rCoord = length(lightningRelVector);
 
-    gl_FrontColor.rgb += 2.0 * flash * vec3 (0.43, 0.57, 1.0) * (1.0 - smoothstep(lightning_range, 5.0 * lightning_range, rCoord));
+  vec3 flashColor = 2.0 * flash * vec3 (0.43, 0.57, 1.0) * (1.0 - smoothstep(lightning_range, 5.0 * lightning_range, rCoord));
+
+    gl_FrontColor.rgb += flashColor;
     gl_FrontColor.rgb = clamp(gl_FrontColor.rgb,0.0,1.0);
 
   // As we get within 100m of the sprite, it is faded out. Equally at large distances it also fades out.