Tentative fix for taxiway line z-fighting within ALS

Effects/lfeat.eff

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <PropertyList>
   <name>Effects/lfeat</name>
-  <inherits-from>Effects/terrain-default</inherits-from>
+  <inherits-from>Effects/runway</inherits-from>
   <parameters>
 	<material>
 	  <ambient type="vec4d">
@@ -19,8 +19,15 @@
 	  <shininess>1.2</shininess>
 	</material>
     <transparent>true</transparent>
+    <raise_vertex type="bool">true</raise_vertex>
   </parameters>
   <technique n="1">
+    <predicate>
+     <equal>
+       <property>/sim/rendering/shaders/skydome</property>
+       <value type="bool" >false</value>
+     </equal>
+    </predicate>
     <pass>
 		<lighting>true</lighting>
 		<depth>

Effects/runway.eff

@@ -84,6 +84,7 @@
     		<moonlight><use>/environment/moonlight</use></moonlight>
    		<quality_level><use>/sim/rendering/shaders/landmass</use></quality_level>
     		<tquality_level><use>/sim/rendering/shaders/transition</use></tquality_level>
+		<raise_vertex type="bool">false</raise_vertex>
 		<!-- 		END fog include -->
 	</parameters>
 	<generate>
@@ -526,6 +527,11 @@
         <type>int</type>
         <value><use>display_ysize</use></value>
       </uniform>
+      <uniform>
+	<name>raise_vertex</name>
+	<type>bool</type>
+	<value>	<use>raise_vertex</use></value>
+      </uniform>
       <uniform>
         <name>texture</name>
         <type>sampler-2d</type>
@@ -542,10 +548,14 @@
         <value>2</value>
         <!-- AMBIENT_AND_DIFFUSE -->
       </uniform>
-      <depth>
+      <!--<depth>
         <function>lequal</function>
-    <!--    <write-mask type="bool">false</write-mask> -->
+      <write-mask type="bool">false</write-mask> 
-      </depth>
+      </depth>-->
+      <alpha-test>
+        <comparison>greater</comparison>
+        <reference type="float">0.4</reference>
+      </alpha-test>
     </pass>
   </technique>
 

Effects/terrain-default.eff

@@ -93,6 +93,7 @@
     <dot_size>1.0</dot_size>
     <dust_resistance>1.0</dust_resistance>
     <rock_strata>0</rock_strata>
+    <raise_vertex type="bool">false</raise_vertex>
     <visibility><use>/environment/ground-visibility-m</use></visibility>
     <avisibility><use>/environment/visibility-m</use></avisibility>
     <lthickness><use>/environment/ground-haze-thickness-m</use></lthickness>
@@ -732,6 +733,11 @@
         <type>int</type>
         <value><use>rock_strata</use></value>
       </uniform>
+      <uniform>
+	<name>raise_vertex</name>
+	<type>bool</type>
+	<value>	<use>raise_vertex</use></value>
+      </uniform>
       <uniform>
         <name>texture</name>
         <type>sampler-2d</type>

Shaders/runway-ALS.frag

@@ -176,23 +176,23 @@ float noise_2000m = Noise2D(rawPos.xy, 2000.0);
 	}
 
 
-const vec4 dust_color  = vec4 (0.76, 0.71, 0.56, 1.0);
+const vec3 dust_color  = vec3 (0.76, 0.71, 0.56);
-const vec4 lichen_color = vec4 (0.17, 0.20, 0.06, 1.0);;
+const vec3 lichen_color = vec3 (0.17, 0.20, 0.06);
 //float snow_alpha;
 
 if (quality_level > 3)
 	{
 
 	// mix vegetation
-	texel = mix(texel, lichen_color, 0.4 * lichen_cover_factor + 0.8 * lichen_cover_factor * 0.5 * (noise_10m + (1.0 - noise_5m))  );
+	texel.rgb = mix(texel.rgb, lichen_color, 0.4 * lichen_cover_factor + 0.8 * lichen_cover_factor * 0.5 * (noise_10m + (1.0 - noise_5m))  );
 	// mix dust
-	texel = mix(texel, dust_color, clamp(0.5 * dust_cover_factor + 3.0 * dust_cover_factor * (((noise_1500m - 0.5) * 0.125)+0.125 ),0.0, 1.0) );
+	texel.rgb = mix(texel.rgb, dust_color, clamp(0.5 * dust_cover_factor + 3.0 * dust_cover_factor * (((noise_1500m - 0.5) * 0.125)+0.125 ),0.0, 1.0) );
 	
     	// mix snow
 	if (relPos.z + eye_alt +500.0 > snowlevel)
 		{
    		snow_alpha = smoothstep(0.75, 0.85, abs(steepness));
-		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));
+		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));
 		}
 	}
 

Shaders/terrain-haze-ultra.vert

@@ -29,9 +29,10 @@ varying vec2 grad_dir;
 varying float mie_angle;
 varying float steepness;
 
-
-
 uniform int colorMode;
+
+uniform bool raise_vertex;
+
 uniform float hazeLayerAltitude;
 uniform float terminator;
 uniform float terrain_alt; 
@@ -87,6 +88,8 @@ void main()
    steepness = dot(normalize(gl_Normal), vec3 (0.0, 0.0, 1.0));
    grad_dir = normalize(gl_Normal.xy);
 
+   if (raise_vertex) gl_Vertex.z+=0.1;
+
 // this code is copied from default.vert
 
     //vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex;
@@ -129,21 +132,6 @@ void main()
     scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, vertex_alt); 
 
 
-// early culling of vertices which can't be seen due to ground haze despite being in aloft visibility range
-
-//float delta_z = hazeLayerAltitude - eye_alt;
-//if (((dist * (relPos.z - delta_z)/relPos.z >  visibility ) && (relPos.z < 0.0) && (delta_z < 0.0) && (dist > 30000.0)))
-if (0==1)
-	{
-	gl_Position = vec4(0.0, 0.0, -1000.0, 1.0); // move outside of view frustrum, gets culled before reaching fragment shader
-   	earthShade = 1.0;
-    	mie_angle = 1.0;
-	yprime_alt = 0.0;
-	}
-else
-	{
-
-
     // branch dependent on daytime
 
 if (terminator < 1000000.0) // the full, sunrise and sunset computation
@@ -284,7 +272,7 @@ float shade_depth =  1.0 * smoothstep (0.6,0.95,ground_scattering) * (1.0-smooth
     gl_BackColor.rgb = constant_term.rgb; //gl_BackColor.a = 0.0;
     gl_FrontColor.a = mie_angle;
     gl_BackColor.a = mie_angle;
-}
+
 	
 }