From 8bf55eec3c41d3c83c386249d1f239bedbeeb2c6 Mon Sep 17 00:00:00 2001
From: Thorsten Renk <thorsten@science-and-fiction.org>
Date: Thu, 17 Mar 2016 14:40:37 +0200
Subject: [PATCH] More work on ALS filter code - noise and vignette for night
 vision, IR vision work

---
 Effects/building.eff           | 10 ++++---
 Effects/cloud.eff              | 25 ++++++++++++++++
 Effects/model-combined.eff     | 52 +++++++++++++++++++++++++++-------
 Effects/model-default.eff      | 37 ++++++++++++++++++++++++
 Effects/skydome.eff            | 12 ++++++++
 Effects/terrain-default.eff    | 12 ++++++++
 Effects/water-inland.eff       | 12 ++++++++
 Effects/water.eff              | 12 ++++++++
 Environment/environment.xml    |  6 +++-
 Shaders/building-ALS.vert      |  6 ++++
 Shaders/filters-ALS.frag       | 36 ++++++++++++++++++++++-
 Shaders/model-ALS-ultra.frag   | 14 +++++++--
 Shaders/terrain-ALS-ultra.vert |  8 +++++-
 preferences.xml                |  1 +
 14 files changed, 224 insertions(+), 19 deletions(-)

diff --git a/Effects/building.eff b/Effects/building.eff
index 70e429dba..58d3e0346 100644
--- a/Effects/building.eff
+++ b/Effects/building.eff
@@ -104,6 +104,7 @@
 		<dust_cover_factor><use>/environment/surface/dust-cover-factor</use></dust_cover_factor>
 		<fogtype><use>/sim/rendering/shaders/skydome</use></fogtype>
 		<fogstructure><use>/environment/fog-structure</use></fogstructure>
+    		<delta_T><use>/environment/surface/delta-T-structure</use></delta_T>
 		<!-- 	END fog include -->
   </parameters>
   <!-- Atmospheric scattering technique with model shader-->
@@ -190,10 +191,11 @@
 	  </texture-unit>
       <program>
         <vertex-shader n="0">Shaders/building-model-ALS-ultra.vert</vertex-shader>
-        <fragment-shader n="1">Shaders/model-ALS-ultra.frag</fragment-shader>
-		<fragment-shader n="2">Shaders/cloud-shadowfunc.frag</fragment-shader>
-		<fragment-shader n="3">Shaders/hazes.frag</fragment-shader>
-		<fragment-shader n="4">Shaders/secondary_lights.frag</fragment-shader>
+        <!--<fragment-shader n="0">Shaders/model-ALS-ultra.frag</fragment-shader>
+		<fragment-shader n="1">Shaders/cloud-shadowfunc.frag</fragment-shader>
+		<fragment-shader n="2">Shaders/hazes.frag</fragment-shader>
+		<fragment-shader n="3">Shaders/secondary_lights.frag</fragment-shader>
+		<fragment-shader n="4">Shaders/filters-ALS.frag</fragment-shader>-->
       </program>
 	</pass>
   </technique>
diff --git a/Effects/cloud.eff b/Effects/cloud.eff
index b133b799f..647d8773b 100644
--- a/Effects/cloud.eff
+++ b/Effects/cloud.eff
@@ -20,7 +20,11 @@
     <use_filtering><use>/sim/rendering/als-filters/use-filtering</use></use_filtering>
     <gamma><use>/sim/rendering/als-filters/gamma</use></gamma>
     <brightness><use>/sim/rendering/als-filters/brightness</use></brightness>
+    <delta_T><use>/environment/surface/delta-T-cloud</use></delta_T>
     <use_night_vision><use>/sim/rendering/als-filters/use-night-vision</use></use_night_vision>
+    <use_IR_vision><use>/sim/rendering/als-filters/use-IR-vision</use></use_IR_vision>
+    <display_xsize><use>/sim/startup/xsize</use></display_xsize>
+    <display_ysize><use>/sim/startup/ysize</use></display_ysize>
   </parameters>
   
   <technique n="9">
@@ -68,6 +72,7 @@
         <vertex-shader>Shaders/3dcloud-ALS.vert</vertex-shader>
         <fragment-shader>Shaders/3dcloud-ALS.frag</fragment-shader>
         <fragment-shader>Shaders/filters-ALS.frag</fragment-shader>
+	<fragment-shader>Shaders/noise.frag</fragment-shader>
         <attribute>
           <name>usrAttr1</name>
           <index>10</index>
@@ -167,6 +172,26 @@
         <type>bool</type>
         <value><use>use_night_vision</use></value>
       </uniform>
+      <uniform>
+        <name>use_IR_vision</name>
+        <type>bool</type>
+        <value><use>use_IR_vision</use></value>
+      </uniform>
+      <uniform>
+        <name>delta_T</name>
+        <type>float</type>
+        <value><use>delta_T</use></value>
+      </uniform>
+      <uniform>
+        <name>display_xsize</name>
+        <type>int</type>
+        <value><use>display_xsize</use></value>
+      </uniform>
+      <uniform>
+        <name>display_ysize</name>
+        <type>int</type>
+        <value><use>display_ysize</use></value>
+      </uniform>  
       <!--<vertex-program-two-side>true</vertex-program-two-side>-->
     </pass>
   </technique>
diff --git a/Effects/model-combined.eff b/Effects/model-combined.eff
index e24078462..662e53ae6 100644
--- a/Effects/model-combined.eff
+++ b/Effects/model-combined.eff
@@ -145,6 +145,7 @@ please see Docs/README.model-combined.eff for documentation
 		<fogtype><use>/sim/rendering/shaders/skydome</use></fogtype>
 		<wetness><use>/environment/surface/wetness</use></wetness>
 		<rnorm><use>/environment/rain-norm</use></rnorm>
+    		<use_IR_vision><use>/sim/rendering/als-filters/use-IR-vision</use></use_IR_vision>
 		<cloudpos1_x><use>/local-weather/cloud-shadows/cloudpos-x[0]</use></cloudpos1_x>
 		<cloudpos1_y><use>/local-weather/cloud-shadows/cloudpos-y[0]</use></cloudpos1_y>
 		<cloudpos2_x><use>/local-weather/cloud-shadows/cloudpos-x[1]</use></cloudpos2_x>
@@ -435,11 +436,12 @@ please see Docs/README.model-combined.eff for documentation
 			   
 			   <program>
 				<vertex-shader n="0">Shaders/model-ALS-ultra.vert</vertex-shader>
-			 	<fragment-shader n="1">Shaders/model-ALS-ultra.frag</fragment-shader>
-				<fragment-shader n="2">Shaders/cloud-shadowfunc.frag</fragment-shader>
-				<fragment-shader n="3">Shaders/hazes.frag</fragment-shader>
-				<fragment-shader n="4">Shaders/secondary_lights.frag</fragment-shader>
-				<fragment-shader n="5">Shaders/noise.frag</fragment-shader>
+			 	<fragment-shader n="0">Shaders/model-ALS-ultra.frag</fragment-shader>
+				<fragment-shader n="1">Shaders/cloud-shadowfunc.frag</fragment-shader>
+				<fragment-shader n="2">Shaders/hazes.frag</fragment-shader>
+				<fragment-shader n="3">Shaders/secondary_lights.frag</fragment-shader>
+				<fragment-shader n="4">Shaders/noise.frag</fragment-shader>
+				<fragment-shader n="5">Shaders/filters-ALS.frag</fragment-shader>
 			   </program>
 			   
 			   <uniform>
@@ -914,11 +916,41 @@ please see Docs/README.model-combined.eff for documentation
     				   <type>float</type>
      				   <value><use>landing_light2_offset</use></value>
      			   </uniform>
-                   <uniform>
-                       <name>landing_light3_offset</name>
-                       <type>float</type>
-                       <value><use>landing_light3_offset</use></value>
-                   </uniform>
+                   	   <uniform>
+                       		   <name>landing_light3_offset</name>
+                       	           <type>float</type>
+                       		   <value><use>landing_light3_offset</use></value>
+                   	   </uniform>
+ 			<uniform>
+        			<name>gamma</name>
+        			<type>float</type>
+       			 <value><use>gamma</use></value>
+      			</uniform>
+      			<uniform>
+        			<name>brightness</name>
+        			<type>float</type>
+       			 <value><use>brightness</use></value>
+      			</uniform>
+      			<uniform>
+        			<name>use_filtering</name>
+        			<type>bool</type>
+        			<value><use>use_filtering</use></value>
+      			</uniform>
+      			<uniform>
+       				 <name>use_night_vision</name>
+        			  <type>bool</type>
+       			 	   <value><use>use_night_vision</use></value>
+      			  </uniform>
+      			  <uniform>
+       			 	<name>use_IR_vision</name>
+        			<type>bool</type>
+       			 	<value><use>use_IR_vision</use></value>
+      			   </uniform>
+     			   <uniform>
+        			<name>delta_T</name>
+        			<type>float</type>
+        			<value><use>delta_T</use></value>
+      			   </uniform>
  			   <uniform>
        				  <name>cloudpos1_x</name>
         			  <type>float</type>
diff --git a/Effects/model-default.eff b/Effects/model-default.eff
index d9e6e8066..fbca771f1 100644
--- a/Effects/model-default.eff
+++ b/Effects/model-default.eff
@@ -26,6 +26,12 @@
 		<moonlight><use>/environment/moonlight</use></moonlight>
 		<fogtype><use>/sim/rendering/shaders/skydome</use></fogtype>
 		<air_pollution><use>/environment/air-pollution-norm</use></air_pollution>
+		<use_filtering><use>/sim/rendering/als-filters/use-filtering</use></use_filtering>
+    		<gamma><use>/sim/rendering/als-filters/gamma</use></gamma>
+    		<brightness><use>/sim/rendering/als-filters/brightness</use></brightness>
+    		<delta_T><use>/environment/surface/delta-T-structure</use></delta_T>
+    		<use_night_vision><use>/sim/rendering/als-filters/use-night-vision</use></use_night_vision>
+    		<use_IR_vision><use>/sim/rendering/als-filters/use-IR-vision</use></use_IR_vision>
 		<display_xsize><use>/sim/startup/xsize</use></display_xsize>
 		<display_ysize><use>/sim/startup/ysize</use></display_ysize>
 		<view_pitch_offset><use>/sim/current-view/pitch-offset-deg</use></view_pitch_offset>
@@ -108,6 +114,7 @@
         <fragment-shader>Shaders/model-ALS-base.frag</fragment-shader>
         <fragment-shader>Shaders/hazes.frag</fragment-shader>
         <fragment-shader>Shaders/secondary_lights.frag</fragment-shader>
+        <fragment-shader>Shaders/filters-ALS.frag</fragment-shader>
       </program>
       <uniform>
         <name>visibility</name>
@@ -174,6 +181,36 @@
         <type>float</type>
         <value><use>air_pollution</use></value>
       </uniform>
+      <uniform>
+        <name>gamma</name>
+        <type>float</type>
+        <value><use>gamma</use></value>
+      </uniform>
+      <uniform>
+        <name>brightness</name>
+        <type>float</type>
+        <value><use>brightness</use></value>
+      </uniform>
+      <uniform>
+        <name>use_filtering</name>
+        <type>bool</type>
+        <value><use>use_filtering</use></value>
+      </uniform>
+      <uniform>
+        <name>use_night_vision</name>
+        <type>bool</type>
+        <value><use>use_night_vision</use></value>
+      </uniform>
+      <uniform>
+        <name>use_IR_vision</name>
+        <type>bool</type>
+        <value><use>use_IR_vision</use></value>
+      </uniform>
+      <uniform>
+        <name>delta_T</name>
+        <type>float</type>
+        <value><use>delta_T</use></value>
+      </uniform>
       <uniform>
         <name>view_pitch_offset</name>
         <type>float</type>
diff --git a/Effects/skydome.eff b/Effects/skydome.eff
index 1d612a6e7..90859d566 100644
--- a/Effects/skydome.eff
+++ b/Effects/skydome.eff
@@ -37,6 +37,8 @@
     <gamma><use>/sim/rendering/als-filters/gamma</use></gamma>
     <brightness><use>/sim/rendering/als-filters/brightness</use></brightness>
     <use_night_vision><use>/sim/rendering/als-filters/use-night-vision</use></use_night_vision>
+    <use_IR_vision><use>/sim/rendering/als-filters/use-IR-vision</use></use_IR_vision>
+    <delta_T>-50.0</delta_T>
     <air_pollution><use>/environment/air-pollution-norm</use></air_pollution>
   </parameters>
   <technique n="8">
@@ -184,6 +186,11 @@
         <type>float</type>
         <value><use>brightness</use></value>
       </uniform>
+      <uniform>
+        <name>delta_T</name>
+        <type>float</type>
+        <value><use>delta_T</use></value>
+      </uniform>
       <uniform>
         <name>use_filtering</name>
         <type>bool</type>
@@ -194,6 +201,11 @@
         <type>bool</type>
         <value><use>use_night_vision</use></value>
       </uniform>
+      <uniform>
+        <name>use_IR_vision</name>
+        <type>bool</type>
+        <value><use>use_IR_vision</use></value>
+      </uniform>
      <uniform>
         <name>view_pitch_offset</name>
         <type>float</type>
diff --git a/Effects/terrain-default.eff b/Effects/terrain-default.eff
index c42c22ba5..492f64537 100644
--- a/Effects/terrain-default.eff
+++ b/Effects/terrain-default.eff
@@ -114,6 +114,7 @@
     <moonlight><use>/environment/moonlight</use></moonlight>
     <season><use>/environment/season</use></season>
     <air_pollution><use>/environment/air-pollution-norm</use></air_pollution>
+    <delta_T><use>/environment/surface/delta-T-soil</use></delta_T>
     <wind_effects><use>/sim/rendering/shaders/wind-effects</use></wind_effects>
     <windE><use>/environment/sea/surface/wind-from-east-fps</use></windE>
     <windN><use>/environment/sea/surface/wind-from-north-fps</use></windN>
@@ -134,6 +135,7 @@
     <gamma><use>/sim/rendering/als-filters/gamma</use></gamma>
     <brightness><use>/sim/rendering/als-filters/brightness</use></brightness>
     <use_night_vision><use>/sim/rendering/als-filters/use-night-vision</use></use_night_vision>
+    <use_IR_vision><use>/sim/rendering/als-filters/use-IR-vision</use></use_IR_vision>
     <cloudpos1_x><use>/local-weather/cloud-shadows/cloudpos-x[0]</use></cloudpos1_x>
     <cloudpos1_y><use>/local-weather/cloud-shadows/cloudpos-y[0]</use></cloudpos1_y>
     <cloudpos2_x><use>/local-weather/cloud-shadows/cloudpos-x[1]</use></cloudpos2_x>
@@ -499,11 +501,21 @@
         <type>bool</type>
         <value><use>use_night_vision</use></value>
       </uniform>
+      <uniform>
+        <name>use_IR_vision</name>
+        <type>bool</type>
+        <value><use>use_IR_vision</use></value>
+      </uniform>
       <uniform>
         <name>use_filtering</name>
         <type>bool</type>
         <value><use>use_filtering</use></value>
       </uniform>
+      <uniform>
+        <name>delta_T</name>
+        <type>float</type>
+        <value><use>delta_T</use></value>
+      </uniform>
       <uniform>
         <name>cloudpos1_x</name>
         <type>float</type>
diff --git a/Effects/water-inland.eff b/Effects/water-inland.eff
index 379577156..a590509c9 100644
--- a/Effects/water-inland.eff
+++ b/Effects/water-inland.eff
@@ -151,6 +151,8 @@
     		<gamma><use>/sim/rendering/als-filters/gamma</use></gamma>
    		<brightness><use>/sim/rendering/als-filters/brightness</use></brightness>
     		<use_night_vision><use>/sim/rendering/als-filters/use-night-vision</use></use_night_vision>
+    		<use_IR_vision><use>/sim/rendering/als-filters/use-IR-vision</use></use_IR_vision>
+    		<delta_T><use>/environment/surface/delta-T-water</use></delta_T>
 		<!-- cloud shadows -->
 		<cloudpos1_x><use>/local-weather/cloud-shadows/cloudpos-x[0]</use></cloudpos1_x>
 		<cloudpos1_y><use>/local-weather/cloud-shadows/cloudpos-y[0]</use></cloudpos1_y>
@@ -635,6 +637,16 @@
         			<type>bool</type>
         			<value><use>use_night_vision</use></value>
       			</uniform>
+      			<uniform>
+        			<name>use_IR_vision</name>
+        			<type>bool</type>
+        			<value><use>use_IR_vision</use></value>
+      			</uniform>
+      			<uniform>
+        			<name>delta_T</name>
+        			<type>float</type>
+        			<value><use>delta_T</use></value>
+      			</uniform>
 			<uniform>
        				<name>cloudpos1_x</name>
         			<type>float</type>
diff --git a/Effects/water.eff b/Effects/water.eff
index 0e3f7ae21..9387c1c68 100644
--- a/Effects/water.eff
+++ b/Effects/water.eff
@@ -143,6 +143,8 @@
     		<gamma><use>/sim/rendering/als-filters/gamma</use></gamma>
    		<brightness><use>/sim/rendering/als-filters/brightness</use></brightness>
     		<use_night_vision><use>/sim/rendering/als-filters/use-night-vision</use></use_night_vision>
+    		<use_IR_vision><use>/sim/rendering/als-filters/use-IR-vision</use></use_IR_vision>
+    		<delta_T><use>/environment/surface/delta-T-water</use></delta_T>
 		<!-- cloud shadows -->
 		<cloudpos1_x><use>/local-weather/cloud-shadows/cloudpos-x[0]</use></cloudpos1_x>
 		<cloudpos1_y><use>/local-weather/cloud-shadows/cloudpos-y[0]</use></cloudpos1_y>
@@ -628,6 +630,16 @@
         			<type>bool</type>
         			<value><use>use_night_vision</use></value>
       			</uniform>
+      			<uniform>
+        			<name>use_IR_vision</name>
+        			<type>bool</type>
+        			<value><use>use_IR_vision</use></value>
+      			</uniform>
+      			<uniform>
+        			<name>delta_T</name>
+        			<type>float</type>
+        			<value><use>delta_T</use></value>
+      			</uniform>
 			<uniform>
        				<name>cloudpos1_x</name>
         			<type>float</type>
diff --git a/Environment/environment.xml b/Environment/environment.xml
index da70f8448..161544e63 100644
--- a/Environment/environment.xml
+++ b/Environment/environment.xml
@@ -460,7 +460,11 @@
     <wetness-set type="double" userarchive="y">0.0</wetness-set>
     <wetness type="double" userarchive="n">0.0</wetness>
     <snow-thickness-factor type="double" userarchive="y">1.0</snow-thickness-factor>
-
+    <delta-T-soil type="double" userarchive="n">0.0</delta-T-soil>
+    <delta-T-rock type="double" userarchive="n">0.0</delta-T-rock>
+    <delta-T-water type="double" userarchive="n">0.0</delta-T-water>
+    <delta-T-cloud type="double" userarchive="n">0.0</delta-T-cloud>
+    <delta-T-structure type="double" userarchive="n">0.0</delta-T-structure>
   </surface>
 
  <!-- definitions for lightning functionality -->
diff --git a/Shaders/building-ALS.vert b/Shaders/building-ALS.vert
index e677feff5..1a53f6593 100644
--- a/Shaders/building-ALS.vert
+++ b/Shaders/building-ALS.vert
@@ -38,6 +38,7 @@ uniform float overcast;
 //uniform float scattering;
 uniform float ground_scattering;
 
+uniform bool use_IR_vision;
 
 // This is the value used in the skydome scattering shader - use the same here for consistency?
 const float EarthRadius = 5800000.0;
@@ -229,6 +230,11 @@ else // the faster, full-day version without lightfields
     yprime_alt = -sqrt(2.0 * EarthRadius * hazeLayerAltitude);
 }
  
+if (use_IR_vision)
+	{
+	light_ambient.rgb = max(light_ambient.rgb, vec3 (0.5, 0.5, 0.5));
+	}
+
 
 // default lighting based on texture and material using the light we have just computed
 
diff --git a/Shaders/filters-ALS.frag b/Shaders/filters-ALS.frag
index 9f7fd4cf9..46d4914c8 100644
--- a/Shaders/filters-ALS.frag
+++ b/Shaders/filters-ALS.frag
@@ -8,10 +8,17 @@
 
 uniform float gamma;
 uniform float brightness;
+uniform float delta_T;
+uniform float osg_SimulationTime;
 
 uniform bool use_filtering;
 uniform bool use_night_vision;
+uniform bool use_IR_vision;
 
+uniform int display_xsize;
+uniform int display_ysize;
+
+float Noise2D(in vec2 coord, in float wavelength);
 
 vec3 gamma_correction (in vec3 color) {
 
@@ -31,7 +38,29 @@ vec3 night_vision (in vec3 color) {
 
 float value = length(color)/1.732;
 
-return vec3 (0.0, 1.0, 0.0) * value;
+vec2 center = vec2 (float(display_xsize) * 0.5, float(display_ysize) * 0.5);
+float noise = Noise2D( vec2 (gl_FragCoord.x + 100.0 * osg_SimulationTime, gl_FragCoord.y + 300.0 * osg_SimulationTime), 4.0);
+
+float fade = 1.0 - smoothstep( 0.3 * display_ysize, 0.55 * display_ysize, length(gl_FragCoord.xy -center));
+
+return vec3 (0.0, 1.0, 0.0) * value * (0.5 + 0.5 * noise) * fade;
+
+}
+
+
+vec3 IR_vision (in vec3 color) {
+
+float value = length(color)/1.732;
+value = 1.0 - value;
+
+float T_mapped = smoothstep(-10.0, 10.0, delta_T);
+
+float gain = mix(T_mapped, value, 0.7);
+//float gain = 0.2 * T_mapped + 0.8 * value * T_mapped;
+if (delta_T < -10.0) {gain = 0.0;}
+
+
+return vec3 (0.7, 0.7, 0.7) * gain;
 
 }
 
@@ -50,6 +79,11 @@ if (use_night_vision)
 	color = night_vision(color);
 	}
 
+else if (use_IR_vision)
+	{
+	color = IR_vision(color);
+	}
+
 return gamma_correction (color);
 
 }
diff --git a/Shaders/model-ALS-ultra.frag b/Shaders/model-ALS-ultra.frag
index 3156d1ed1..65278c758 100644
--- a/Shaders/model-ALS-ultra.frag
+++ b/Shaders/model-ALS-ultra.frag
@@ -77,6 +77,8 @@ uniform float landing_light1_offset;
 uniform float landing_light2_offset;
 uniform float landing_light3_offset;
 
+uniform bool use_IR_vision;
+
 // constants needed by the light and fog computations ###################################################
 
 const float EarthRadius = 5800000.0;
@@ -103,7 +105,7 @@ vec3 rayleigh_out_shift(in vec3 color, in float outscatter);
 vec3 get_hazeColor(in float lightArg);
 vec3 searchlight();
 vec3 landing_light(in float offset, in float offsetv);
-
+vec3 filter_combined (in vec3 color) ;
 
 
 float light_func (in float x, in float a, in float b, in float c, in float d, in float e)
@@ -213,6 +215,7 @@ void main (void)
         }
 
 
+
     /// END light
 
     /// BEGIN grain overlay
@@ -297,7 +300,11 @@ void main (void)
 
 
     vec4 Diffuse  = light_diffuse * nDotVP;
-    Diffuse.rgb += secondary_light * light_distance_fading(dist);
+    Diffuse.rgb += secondary_light * light_distance_fading(dist);	
+    if (use_IR_vision)
+	{
+	Diffuse.rgb = max(Diffuse.rgb, vec3 (0.5, 0.5, 0.5));
+	}
     vec4 Specular = gl_FrontMaterial.specular * light_diffuse * pf + gl_FrontMaterial.specular * light_ambient * pf1;
     Specular+=  gl_FrontMaterial.specular * pow(max(0.0,-dot(N,normalize(vertVec))),gl_FrontMaterial.shininess) * vec4(secondary_light,1.0);
 
@@ -558,5 +565,8 @@ void main (void)
 
 
       fragColor.rgb = mix(hazeColor +secondary_light * fog_backscatter(mvisibility), fragColor.rgb,transmission);
+
+
+      fragColor.rgb = filter_combined(fragColor.rgb);
     gl_FragColor = fragColor;
     }
diff --git a/Shaders/terrain-ALS-ultra.vert b/Shaders/terrain-ALS-ultra.vert
index 4ce7efa65..9792d59c3 100644
--- a/Shaders/terrain-ALS-ultra.vert
+++ b/Shaders/terrain-ALS-ultra.vert
@@ -43,6 +43,8 @@ uniform float ground_scattering;
 uniform float eye_alt;
 uniform float moonlight;
 
+uniform bool use_IR_vision;
+
 uniform mat4 osg_ViewMatrixInverse;
 
 float earthShade;
@@ -72,7 +74,7 @@ void main()
   vec4 light_diffuse;
   vec4 light_ambient;
   vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
-  vec3 moonLightColor = vec3 (0.095, 0.095, 0.15) * moonlight;
+  vec3 moonLightColor = vec3 (0.095, 0.095, 0.15) * moonlight + vec3 (0.005, 0.005, 0.005);
 
   //float yprime_alt;
   float yprime;
@@ -266,6 +268,10 @@ float shade_depth =  1.0 * smoothstep (0.6,0.95,ground_scattering) * (1.0-smooth
    light_ambient.rgb = light_ambient.rgb * (1.0 - shade_depth);
    light_diffuse.rgb = light_diffuse.rgb * (1.0 + 1.2 * shade_depth);
 
+if (use_IR_vision)
+	{
+	light_ambient.rgb = max(light_ambient.rgb, vec3 (0.5, 0.5, 0.5));
+	}
 
 
 // default lighting based on texture and material using the light we have just computed
diff --git a/preferences.xml b/preferences.xml
index bb540aeee..1dbbfaa34 100644
--- a/preferences.xml
+++ b/preferences.xml
@@ -297,6 +297,7 @@ Started September 2000 by David Megginson, david@megginson.com
  	 <gamma type="float">0.0</gamma>
  	 <brightness type="float">1.0</brightness>
 	 <use-night-vision type="bool">false</use-night-vision>
+	 <use-IR-vision type="bool">false</use-IR-vision>
       </als-filters>
     </rendering>
     <model-hz type="int">120</model-hz>