From 40e871a9113c389944c0aeebf376399d10340ab8 Mon Sep 17 00:00:00 2001
From: Erik Hofman <erik@ehofman.com>
Date: Tue, 19 Jan 2021 11:10:44 +0100
Subject: [PATCH] Implement a simple snow shader for the low quality levels

---
 Materials/regions/global-summer.xml  | 33 ++++++++++-
 Shaders/airfield-ALS.frag            |  6 ++
 Shaders/drunway-ALS.frag             |  6 ++
 Shaders/runway-ALS.frag              |  6 ++
 Shaders/terrain-ALS-detailed.frag    |  6 ++
 gui/dialogs/environment-settings.xml | 84 +++++-----------------------
 6 files changed, 68 insertions(+), 73 deletions(-)

diff --git a/Materials/regions/global-summer.xml b/Materials/regions/global-summer.xml
index 4b8a1f688..6854b0fa9 100644
--- a/Materials/regions/global-summer.xml
+++ b/Materials/regions/global-summer.xml
@@ -391,13 +391,42 @@
     <texture>Terrain/water.png</texture>
   </material>
 
+  <material>
+    <effect>Effects/water-inland</effect>
+    <name>Stream</name>
+    <name>Canal</name>
+    <texture>Terrain/water-lake.png</texture>
+    <xsize>400</xsize>
+    <ysize>400</ysize>
+    <ambient>
+      <r>0.0</r>
+      <g>0.0</g>
+      <b>0.0</b>
+      <a>1.0</a>
+    </ambient>
+    <diffuse>
+      <r>0.5</r>
+      <g>0.5</g>
+      <b>0.5</b>
+      <a>1.0</a>
+    </diffuse>
+    <specular>
+      <r>0.3</r>
+      <g>0.3</g>
+      <b>0.3</b>
+      <a>1.0</a>
+    </specular>
+    <shininess>1.2</shininess>
+    <solid>0</solid>
+    <rolling-friction>1.5</rolling-friction>
+    <bumpiness>0.6</bumpiness>
+  </material>
+
   <material>
     <effect>Effects/water-inland</effect>
     <name>Lake</name>
     <name>Pond</name>
     <name>Reservoir</name>
-    <name>Stream</name>
-    <name>Canal</name>
     <name>Lagoon</name>
     <name>Estuary</name>
     <name>Watercourse</name>
diff --git a/Shaders/airfield-ALS.frag b/Shaders/airfield-ALS.frag
index c33cc17fe..e039ddcfc 100644
--- a/Shaders/airfield-ALS.frag
+++ b/Shaders/airfield-ALS.frag
@@ -193,6 +193,12 @@ float noise_2000m = Noise3D(worldPos.xyz, 2000.0);
 	if (dist < 1000.0){ noise_term = noise_term + 0.3 * (noise_1m -0.5) * (1.0 - smoothstep(500.0 , 1000.0 , dist)  );}
 	snow_texel.a = snow_texel.a * 0.2+0.8* smoothstep(0.2,0.8, 0.3 +noise_term + snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
 	}
+    else if (relPos.z + eye_alt +500.0 > snowlevel && tquality_level > 2)
+        {
+            float snow_alpha = 0.5+0.5* smoothstep(0.2,0.8, 0.3 + snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
+//          texel = vec4(dot(vec3(0.2989, 0.5870, 0.1140), texel.rgb));
+            texel = mix(texel, vec4(1.0), snow_alpha* smoothstep(snowlevel, snowlevel+200.0,  (relPos.z + eye_alt)));
+        }
 
 if (use_overlay == 1)
 	{
diff --git a/Shaders/drunway-ALS.frag b/Shaders/drunway-ALS.frag
index b40913b24..85056dee4 100644
--- a/Shaders/drunway-ALS.frag
+++ b/Shaders/drunway-ALS.frag
@@ -245,6 +245,12 @@ if (quality_level > 3)
 		texel = mix(texel, snow_texel, snow_texel.a* smoothstep(snowlevel, snowlevel+200.0,  snow_alpha * (relPos.z + eye_alt)+ (noise_2000m + 0.1 * noise_10m -0.55) *400.0));
 		}
 	}
+else if (relPos.z + eye_alt +500.0 > snowlevel)
+        {
+            float snow_alpha = 0.5+0.5* smoothstep(0.2,0.8, 0.3 + snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
+//          texel = vec4(dot(vec3(0.2989, 0.5870, 0.1140), texel.rgb));
+            texel = mix(texel, vec4(1.0), snow_alpha* smoothstep(snowlevel, snowlevel+200.0,  (relPos.z + eye_alt)));
+        }
 
 
 
diff --git a/Shaders/runway-ALS.frag b/Shaders/runway-ALS.frag
index 56129de64..7bbb6d49f 100644
--- a/Shaders/runway-ALS.frag
+++ b/Shaders/runway-ALS.frag
@@ -248,6 +248,12 @@ if (quality_level > 3)
 		texel.rgb = mix(texel.rgb, snow_texel.rgb, snow_texel.a* smoothstep(snowlevel, snowlevel+200.0,  snow_alpha * (relPos.z + eye_alt)+ (noise_2000m + 0.1 * noise_10m -0.55) *400.0));
 		}
 	}
+else if (relPos.z + eye_alt +500.0 > snowlevel)
+        {
+            float snow_alpha = 0.1+0.4* smoothstep(0.2,0.8, 0.3 + snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
+//          texel = vec4(dot(vec3(0.2989, 0.5870, 0.1140), texel.rgb));
+            texel = mix(texel, vec4(1.0), snow_alpha* smoothstep(snowlevel, snowlevel+200.0,  (relPos.z + eye_alt)));
+        }
 
 
 
diff --git a/Shaders/terrain-ALS-detailed.frag b/Shaders/terrain-ALS-detailed.frag
index f59040dbd..8bb9922eb 100644
--- a/Shaders/terrain-ALS-detailed.frag
+++ b/Shaders/terrain-ALS-detailed.frag
@@ -279,6 +279,12 @@ if (quality_level > 3)
 		texel = mix(texel, snow_texel, snow_texel.a* smoothstep(snowlevel, snowlevel+200.0,  snow_alpha * (relPos.z + eye_alt)+ (noise_2000m + 0.1 * noise_10m -0.55) *400.0));
 		}
 	}
+else if (relPos.z + eye_alt +500.0 > snowlevel)
+        {
+            float snow_alpha = 0.5+0.5* smoothstep(0.2,0.8, 0.3 + snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
+//          texel = vec4(dot(vec3(0.2989, 0.5870, 0.1140), texel.rgb));
+            texel = mix(texel, vec4(1.0), snow_alpha* smoothstep(snowlevel, snowlevel+200.0,  (relPos.z + eye_alt)));
+        }
 
 
 
diff --git a/gui/dialogs/environment-settings.xml b/gui/dialogs/environment-settings.xml
index e4d41a913..ea6a4b63e 100644
--- a/gui/dialogs/environment-settings.xml
+++ b/gui/dialogs/environment-settings.xml
@@ -38,47 +38,6 @@
 
   <hrule/>
 
-  <group>
-    <layout>table</layout>
-    <default-padding>5</default-padding>
-
-    <text>
-      <row>0</row>
-      <col>0</col>
-      <label>  Ground Textures:</label>
-      <halign>left</halign>
-    </text>
-    <combo>
-      <row>0</row>
-      <col>1</col>
-      <pref-width>90</pref-width>
-      <name>season</name>
-      <halign>left</halign>
-      <live>true</live>
-      <property>/sim/startup/season</property>
-      <value>summer</value>
-      <value>winter</value>
-      <binding>
-        <command>dialog-apply</command>
-        <object-name>season</object-name>
-      </binding>
-    </combo>
-
-    <button>
-      <row>0</row>
-      <col>2</col>
-      <legend>Reload Scenery</legend>
-      <binding>
-        <command>reinit</command>
-        <subsystem>scenery</subsystem>
-      </binding>
-    </button>
-    
-  </group>
-    
-  <hrule/>
-  
-    
   <group>
     <layout>vbox</layout>
     <halign>left</halign>
@@ -88,42 +47,25 @@
     </text>
     
     <group>
-      <layout>vbox</layout>
+      <layout>hbox</layout>
       <halign>left</halign>
       <text>
         <label> </label>
         <halign>left</halign>
       </text>
 
-      <group>
-        <layout>hbox</layout>
-
-        <checkbox>
-          <label> Climate updates weather</label>
-          <name>climate-update</name>
-          <property>/environment/climate/weather-update</property>
-          <live>true</live>
-          <binding>
-            <command>dialog-apply</command>
-          </binding>
-          <binding>
-            <command>property-toggle</command>
-          </binding>
-        </checkbox>
-
-        <checkbox>
-          <label> Climate updates environment</label>
-          <name>climate-update</name>
-          <property>/environment/climate/environment-update</property>
-          <live>true</live>
-          <binding>
-            <command>dialog-apply</command>
-          </binding>
-          <binding>
-            <command>property-toggle</command>
-          </binding>
-        </checkbox>
-      </group>
+      <checkbox>
+        <label> Climate updates environment</label>
+        <name>climate-update</name>
+        <property>/environment/climate/environment-update</property>
+        <live>true</live>
+        <binding>
+          <command>dialog-apply</command>
+        </binding>
+        <binding>
+          <command>property-toggle</command>
+      </binding>
+      </checkbox>
 
       <checkbox>
         <label> Set maximum snow level from weather</label>