ALS road shader: add procedural snow, make lighting switchable

Effects/road.eff

@@ -17,8 +17,11 @@
 	<grain-texture-enabled type="int">0</grain-texture-enabled>
 	<grain-magnification type="float">50</grain-magnification>
 	<lightmap-color type="vec3d" n="0"> 0.8 0.8 1.0 </lightmap-color>
+    	<snow_level><use>/environment/snow-level-m</use></snow_level>
+    	<snow_thickness_factor><use>/environment/surface/snow-thickness-factor</use></snow_thickness_factor>
 	<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-light-factor><use>/environment/lightmap-factor</use></road-light-factor>
   </parameters>
 
    <technique n="3">
@@ -493,6 +496,14 @@
 				   </value>
 			   </uniform>
 
+			   <uniform>
+				   <name>streetlight_factor</name>
+				   <type>float</type>
+				   <value>
+					   <use>road-light-factor</use>
+				   </value>
+			   </uniform>
+			   
 
 			   <!-- use a grain texture map-->
 		  	   <uniform>
@@ -511,7 +522,7 @@
 				   </value>
 		  	   </uniform>
 
-			   <!-- simulate wetness and rain-->
+			   <!-- simulate wetness, snow and rain-->
 		  	   <uniform>
 				   <name>rain_enabled</name>
 				   <type>int</type>
@@ -520,6 +531,18 @@
 				   </value>
 		  	   </uniform>
 
+			   <uniform>
+        			   <name>snowlevel</name>
+        			   <type>float</type>
+        			   <value><use>snow_level</use></value>
+      			   </uniform>
+
+			   <uniform>
+				   <name>snow_thickness_factor</name>
+				   <type>float</type>
+				   <value><use>snow_thickness_factor</use></value>
+			   </uniform>
+
 			   <!-- set the amount of ambient light correction 0.0 - 1.0  -->
 			   <uniform>
 				   <name>amb_correction</name>

Shaders/road-ALS-ultra.frag

@@ -56,6 +56,7 @@ uniform float grain_magnification;
 uniform float wetness;
 uniform float rain_norm;
 uniform float road_traffic_density;
+uniform float streetlight_factor;
 
 uniform float avisibility;
 uniform float cloud_self_shading;
@@ -69,6 +70,8 @@ uniform float terminator;
 uniform float terrain_alt;
 uniform float visibility;
 uniform float air_pollution;
+uniform float snowlevel;
+uniform float snow_thickness_factor;
 
 uniform float osg_SimulationTime;
 
@@ -98,6 +101,7 @@ float alt_factor(in float eye_alt, in float vertex_alt);
 float light_distance_fading(in float dist);
 float fog_backscatter(in float avisibility);
 float rand2D(in vec2 co);
+float Noise2D(in vec2 coord, in float wavelength);
 
 vec3 rayleigh_out_shift(in vec3 color, in float outscatter);
 vec3 get_hazeColor(in float lightArg);
@@ -183,6 +187,11 @@ void main (void)
     vec3 mixedcolor;
     vec3 N = vec3(0.0,0.0,1.0);
  
+    // noise
+
+    float noise_1m = Noise2D(rawpos.xy, 1.0); 
+    float noise_5m = Noise2D(rawpos.xy, 5.0);
+
     // road type characteristics
 
     float rtype_traffic_density = 0.0;
@@ -242,6 +251,8 @@ void main (void)
 
     float ct = dot(normalize(up), normalize(vertVec));
 
+    vec3 relPos = (gl_ModelViewMatrixInverse * vec4 (vertVec,0.0)).xyz;		
+
     /// END geometry for light
 
 
@@ -292,15 +303,32 @@ void main (void)
     /// END grain overlay
 
 
-    /// BEGIN procedural cars
+    /// BEGIN procedural textures - cars and snow
-
-	float cTag = 0.0;
-	float cPresent = 0.0;
 
 	vec2 roadCoords = gl_TexCoord[0].st;
 	roadCoords.s *=8.0;
 	roadCoords.s = fract(roadCoords.s);
 
+	
+
+	vec4 snow_texel = vec4 (0.95, 0.95, 0.95, 1.0);
+	float noise_term = 0.5 * (noise_5m - 0.5);
+	noise_term +=  0.5 * (noise_1m - 0.5);
+	snow_texel.a = snow_texel.a * 0.2+0.8* smoothstep(0.2,0.8, 0.3 +noise_term + 0.5*snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
+
+	float noise_2000m = 0.0; 
+	float noise_10m = 0.0;
+		
+	float snowLaneShape =  smoothstep(0.20, 0.28, roadCoords.s) * (1.0-smoothstep(0.42, 0.5, roadCoords.s));
+	snowLaneShape += smoothstep(0.6, 0.68, roadCoords.s) * (1.0-smoothstep(0.82, 0.9, roadCoords.s));
+	snow_texel.a *= (1.0 - 0.3* snowLaneShape * rtype_traffic_density);
+
+	texel.rgb = mix(texel.rgb, snow_texel.rgb, snow_texel.a* smoothstep(snowlevel, snowlevel+200.0,  1.0 * (relPos.z + eye_alt)+ (noise_2000m + 0.1 * noise_10m -0.55) *400.0));
+
+	float cTag = 0.0;
+	float cPresent = 0.0;
+
+
 	if (road_traffic_enabled == 1)
 		{
 		float cSign = 1.0;
@@ -329,9 +357,9 @@ void main (void)
 		float cPos = cTag;
 		if (cSign > 0.0) {cPos = 1.0 - cPos;}
 		float cShape = smoothstep(0.0, 0.05, cPos) * (1.0-smoothstep(0.35, 0.4, cPos));
+		
 		float laneShape =  smoothstep(0.25, 0.28, roadCoords.s) * (1.0-smoothstep(0.42, 0.45, roadCoords.s));
 		laneShape += smoothstep(0.65, 0.68, roadCoords.s) * (1.0-smoothstep(0.82, 0.85, roadCoords.s));
-
 		cShape *= laneShape;
 
 		texel.rgb = mix(texel.rgb, cColor, cPresent * cShape); 
@@ -395,7 +423,7 @@ void main (void)
         {pf1 = pow(nDotHV1, 0.5*gl_FrontMaterial.shininess);}
   
 
-    vec3 relPos = (gl_ModelViewMatrixInverse * vec4 (vertVec,0.0)).xyz;		
+
     if (cloud_shadow_flag == 1) 
 	{
 	light_diffuse = light_diffuse * shadow_func(relPos.x, relPos.y, 1.0, dist);
@@ -427,7 +455,7 @@ void main (void)
     Specular+=  gl_FrontMaterial.specular * pow(max(0.0,-dot(N,normalize(vertVec))),gl_FrontMaterial.shininess) * vec4(secondary_light,1.0);
 
     //vec4 color = gl_Color + Diffuse * gl_FrontMaterial.diffuse;
-	vec4 color = Diffuse * gl_FrontMaterial.diffuse;
+    vec4 color = Diffuse * gl_FrontMaterial.diffuse;
     color = clamp( color, 0.0, 1.0 );
 
 
@@ -531,7 +559,6 @@ void main (void)
 
     // set ambient adjustment to remove bluiness with user input
     float ambient_offset = clamp(amb_correction, -1.0, 1.0);
-    //vec4 ambient = gl_LightModel.ambient + gl_LightSource[0].ambient;
     vec4 ambient = gl_LightModel.ambient + light_ambient;
     vec4 ambient_Correction = vec4(ambient.rg, ambient.b * 0.6, 1.0)
         * ambient_offset ;
@@ -558,7 +585,7 @@ void main (void)
 	vec3 pLMColor = streetlight_color;//vec3 (0.941, 0.682, 0.086);
 
 	float pLMIntensity = smoothstep(0.0, 0.4, roadCoords.s) * (1.0 - smoothstep(0.6, 1.0, roadCoords.s));
-	pLMIntensity = 0.5 * rtype_base_illumination + 0.1 * max(0.0,sin(4.0 * roadCoords.t));
+	pLMIntensity = 0.5 * rtype_base_illumination + 0.1 * max(0.0,sin(4.0 * roadCoords.t)) * streetlight_factor;
 
 	pLMColor *= pLMIntensity;