Domain tiling effect for ALS tree shader

Effects/tree.eff

@@ -36,6 +36,7 @@
 		<quality_level><use>/sim/rendering/shaders/landmass</use></quality_level>
 		<tquality_level><use>/sim/rendering/shaders/transition</use></tquality_level>
 		<wind_effects><use>/sim/rendering/shaders/wind-effects</use></wind_effects>
+		<forest_effects><use>/sim/rendering/shaders/forest</use></forest_effects>
 		<windE><use>/environment/sea/surface/wind-from-east-fps</use></windE>
 		<windN><use>/environment/sea/surface/wind-from-north-fps</use></windN>
 		<cloudpos1_x><use>/local-weather/cloud-shadows/cloudpos-x[0]</use></cloudpos1_x>
@@ -119,6 +120,7 @@
 			<alpha-to-coverage>true</alpha-to-coverage>
       <program>
         <vertex-shader>Shaders/tree-haze.vert</vertex-shader>
+        <vertex-shader>Shaders/noise.frag</vertex-shader>
 	<vertex-shader>Shaders/cloud-shadowfunc.frag</vertex-shader>
         <fragment-shader>Shaders/tree-haze.frag</fragment-shader>
       </program>
@@ -427,6 +429,11 @@
       <type>int</type>
       <value><use>wind_effects</use></value>
      </uniform>
+     <uniform>
+      <name>forest_effects</name>
+      <type>int</type>
+      <value><use>forest_effects</use></value>
+     </uniform>
     </pass>
   </technique>
 	
@@ -472,6 +479,7 @@
 			</alpha-test>
       <program>
         <vertex-shader>Shaders/tree-haze.vert</vertex-shader>
+        <vertex-shader>Shaders/noise.frag</vertex-shader>
 	<vertex-shader>Shaders/cloud-shadowfunc.frag</vertex-shader>
         <fragment-shader>Shaders/tree-haze.frag</fragment-shader>
       </program>
@@ -780,6 +788,11 @@
       <type>int</type>
       <value><use>wind_effects</use></value>
      </uniform>
+     <uniform>
+      <name>forest_effects</name>
+      <type>int</type>
+      <value><use>forest_effects</use></value>
+     </uniform>
     </pass>
   </technique>
   	

Shaders/noise.frag

@@ -0,0 +1,192 @@
+// -*-C++-*-
+
+// This is a library of noise functions, taking a coordinate vector and a wavelength
+// as input and returning a number [0:1] as output.
+
+// * Noise2D(in vec2 coord, in float wavelength) is 2d Perlin noise
+// * Noise3D(in vec3 coord, in float wavelength) is 3d Perlin noise
+// * DotNoise2D(in vec2 coord, in float wavelength, in float fractionalMaxDotSize, in float dDensity)
+//   is sparse dot noise and takes a dot density parameter
+// * VoronoiNoise2D(in vec2 coord, in float wavelength, in float xrand, in float yrand)
+//   is a function mapping the terrain into random domains, based on Voronoi tiling of a regular grid
+//   distorted with xrand and yrand
+
+// Thorsten Renk 2014
+
+#version 120
+
+
+float rand2D(in vec2 co){
+    return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
+}
+
+float rand3D(in vec3 co){
+    return fract(sin(dot(co.xyz ,vec3(12.9898,78.233,144.7272))) * 43758.5453);
+}
+
+float cosine_interpolate(in float a, in float b, in float x)
+{
+	float ft = x * 3.1415927;
+	float f = (1.0 - cos(ft)) * .5;
+
+	return  a*(1.0-f) + b*f;
+}
+
+float simple_interpolate(in float a, in float b, in float x)
+{
+return a + smoothstep(0.0,1.0,x) * (b-a);
+}
+
+float interpolatedNoise2D(in float x, in float y)
+{
+      float integer_x    = x - fract(x);
+      float fractional_x = x - integer_x;
+
+      float integer_y    = y - fract(y);
+      float fractional_y = y - integer_y;
+
+      float v1 = rand2D(vec2(integer_x, integer_y));
+      float v2 = rand2D(vec2(integer_x+1.0, integer_y));
+      float v3 = rand2D(vec2(integer_x, integer_y+1.0));
+      float v4 = rand2D(vec2(integer_x+1.0, integer_y +1.0));
+
+      float i1 = simple_interpolate(v1 , v2 , fractional_x);
+      float i2 = simple_interpolate(v3 , v4 , fractional_x);
+
+      return simple_interpolate(i1 , i2 , fractional_y);
+}
+
+float interpolatedNoise3D(in float x, in float y, in float z)
+{
+      float integer_x    = x - fract(x);
+      float fractional_x = x - integer_x;
+
+      float integer_y    = y - fract(y);
+      float fractional_y = y - integer_y;
+
+      float integer_z    = z - fract(z);
+      float fractional_z = z - integer_z;
+
+      float v1 = rand3D(vec3(integer_x, integer_y, integer_z));
+      float v2 = rand3D(vec3(integer_x+1.0, integer_y, integer_z));
+      float v3 = rand3D(vec3(integer_x, integer_y+1.0, integer_z));
+      float v4 = rand3D(vec3(integer_x+1.0, integer_y +1.0, integer_z));
+
+      float v5 = rand3D(vec3(integer_x, integer_y, integer_z+1.0));
+      float v6 = rand3D(vec3(integer_x+1.0, integer_y, integer_z+1.0));
+      float v7 = rand3D(vec3(integer_x, integer_y+1.0, integer_z+1.0));
+      float v8 = rand3D(vec3(integer_x+1.0, integer_y +1.0, integer_z+1.0));
+
+
+      float i1 = simple_interpolate(v1,v5, fractional_z);
+      float i2 = simple_interpolate(v2,v6, fractional_z);
+      float i3 = simple_interpolate(v3,v7, fractional_z);
+      float i4 = simple_interpolate(v4,v8, fractional_z);
+
+      float ii1 = simple_interpolate(i1,i2,fractional_x);
+      float ii2 = simple_interpolate(i3,i4,fractional_x);
+ 
+
+      return simple_interpolate(ii1 , ii2 , fractional_y);
+}
+
+
+float Noise2D(in vec2 coord, in float wavelength)
+{
+return interpolatedNoise2D(coord.x/wavelength, coord.y/wavelength);
+
+}
+
+float Noise3D(in vec3 coord, in float wavelength)
+{
+return interpolatedNoise3D(coord.x/wavelength, coord.y/wavelength, coord.z/wavelength);
+}
+
+float dotNoise2D(in float x, in float y, in float fractionalMaxDotSize, in float dDensity)
+{
+	float integer_x    = x - fract(x);
+    float fractional_x = x - integer_x;
+
+    float integer_y    = y - fract(y);
+    float fractional_y = y - integer_y;
+
+	if (rand2D(vec2(integer_x+1.0, integer_y +1.0)) > dDensity)
+		{return 0.0;}
+
+    float xoffset = (rand2D(vec2(integer_x, integer_y)) -0.5);
+    float yoffset = (rand2D(vec2(integer_x+1.0, integer_y)) - 0.5);
+    float dotSize = 0.5 * fractionalMaxDotSize * max(0.25,rand2D(vec2(integer_x, integer_y+1.0)));
+
+	
+	vec2 truePos = vec2 (0.5 + xoffset * (1.0 - 2.0 * dotSize) , 0.5 + yoffset * (1.0 -2.0 * dotSize));
+
+	float distance = length(truePos - vec2(fractional_x, fractional_y));
+	
+	return 1.0 - smoothstep (0.3 * dotSize, 1.0* dotSize, distance);
+}
+
+float DotNoise2D(in vec2 coord, in float wavelength, in float fractionalMaxDotSize, in float dDensity)
+{
+return dotNoise2D(coord.x/wavelength, coord.y/wavelength, fractionalMaxDotSize, dDensity);
+}
+
+
+float voronoiNoise2D(in float x, in float y, in float xrand, in float yrand)
+{
+	float integer_x    = x - fract(x);
+    float fractional_x = x - integer_x;
+
+    float integer_y    = y - fract(y);
+    float fractional_y = y - integer_y;
+
+	float val[4];
+	
+	val[0] = rand2D(vec2(integer_x, integer_y));
+	val[1] = rand2D(vec2(integer_x+1.0, integer_y));
+	val[2] = rand2D(vec2(integer_x, integer_y+1.0));
+	val[3] = rand2D(vec2(integer_x+1.0, integer_y+1.0));
+
+	float xshift[4];
+	
+	xshift[0] = xrand * (rand2D(vec2(integer_x+0.5, integer_y)) - 0.5);
+	xshift[1] = xrand * (rand2D(vec2(integer_x+1.5, integer_y)) -0.5);
+	xshift[2] = xrand * (rand2D(vec2(integer_x+0.5, integer_y+1.0))-0.5);
+	xshift[3] = xrand * (rand2D(vec2(integer_x+1.5, integer_y+1.0))-0.5);
+
+	float yshift[4];
+	
+	yshift[0] = yrand * (rand2D(vec2(integer_x, integer_y +0.5)) - 0.5);
+	yshift[1] = yrand * (rand2D(vec2(integer_x+1.0, integer_y+0.5)) -0.5);
+	yshift[2] = yrand * (rand2D(vec2(integer_x, integer_y+1.5))-0.5);
+	yshift[3] = yrand * (rand2D(vec2(integer_x+1.5, integer_y+1.5))-0.5);
+	
+	
+	float dist[4];
+	
+	dist[0] = sqrt((fractional_x + xshift[0]) * (fractional_x + xshift[0]) + (fractional_y + yshift[0]) * (fractional_y + yshift[0]));
+	dist[1] = sqrt((1.0 -fractional_x + xshift[1]) * (1.0-fractional_x+xshift[1]) + (fractional_y +yshift[1]) * (fractional_y+yshift[1]));
+	dist[2] = sqrt((fractional_x + xshift[2]) * (fractional_x + xshift[2]) + (1.0-fractional_y +yshift[2]) * (1.0-fractional_y + yshift[2]));
+	dist[3] = sqrt((1.0-fractional_x + xshift[3]) * (1.0-fractional_x + xshift[3]) + (1.0-fractional_y +yshift[3]) * (1.0-fractional_y + yshift[3]));
+	
+
+
+	int i, i_min;
+	float dist_min = 100.0;
+	for (i=0; i<4;i++)
+		{
+		if (dist[i] < dist_min)
+			{
+			dist_min = dist[i];
+			i_min = i;
+			}
+		}
+	
+	return val[i_min];
+	//return val[0];
+	
+}
+
+float VoronoiNoise2D(in vec2 coord, in float wavelength, in float xrand, in float yrand)	
+{
+return voronoiNoise2D(coord.x/wavelength, coord.y/wavelength, xrand, yrand);
+}

Shaders/tree-haze.vert

@@ -25,6 +25,7 @@ varying float yprime_alt;
 
 uniform int colorMode;
 uniform int wind_effects;
+uniform int forest_effects;
 uniform float hazeLayerAltitude;
 uniform float terminator;
 uniform float terrain_alt; 
@@ -45,6 +46,7 @@ float earthShade;
 float mie_angle;
 
 float shadow_func (in float x, in float y, in float noise, in float dist);
+float VoronoiNoise2D(in vec2 coord, in float wavelength, in float xrand, in float yrand);	
 
 // This is the value used in the skydome scattering shader - use the same here for consistency?
 const float EarthRadius = 5800000.0;
@@ -105,6 +107,13 @@ void main()
   	position.y = position.y + position.z * (sin(osg_SimulationTime * 1.8 + (gl_Color.x + gl_Color.y + gl_Color.z) * 0.01) + 1.0) * 0.0025 * WindE;
 	}
 	
+  // Scale by random domains	
+  if (forest_effects > 0)
+	{
+	float voronoi = 0.5 + 1.0 * VoronoiNoise2D(gl_Color.xy, 200.0, 1.5, 1.5);	
+	position.xyz = position.xyz * voronoi;  
+ 	}
+ 
   // Move to correct location (stored in gl_Color)
   position = position + gl_Color.xyz;
   gl_Position   = gl_ModelViewProjectionMatrix * vec4(position,1.0);

gui/dialogs/shaders-lightfield.xml

@@ -173,6 +173,30 @@
 		</empty>
 	</group>
 
+	<group>
+		<layout>hbox</layout>
+		<halign>right</halign>
+		<text>
+			<label>Forest</label>
+		</text>
+		<slider>
+			<name>forest</name>
+			<min>0.0</min>
+			<max>1.0</max>
+			<step>1.0</step>
+			<fraction>0.17</fraction>
+			<live>true</live>
+			<property>/sim/rendering/shaders/forest</property>
+			<binding>
+				<command>dialog-apply</command>
+				<object-name>forest</object-name>
+			</binding>
+		</slider>
+		<empty>
+			<pref-width>55</pref-width>
+		</empty>
+	</group>
+
 	<group>
 		<layout>hbox</layout>
 		<halign>right</halign>
@@ -196,7 +220,7 @@
 			<pref-width>55</pref-width>
 		</empty>
 	</group>
-	
+	<!--
 	<group>
 		<layout>hbox</layout>
 		<visible>
@@ -302,7 +326,7 @@
 			<live>true</live>
 			<property>/sim/rendering/dome-density</property>
 		</text>
-	</group>
+	</group>-->
 
 	<group>
 		<layout>hbox</layout>

preferences.xml

@@ -146,6 +146,7 @@ Started September 2000 by David Megginson, david@megginson.com
 				<urban type="float" userarchive="y">1.0</urban>
 				<water type="float" userarchive="y">1.0</water>
 				<wind-effects type="float" userarchive="y">0.0</wind-effects>
+				<forest type="float" userarchive="y">0.0</forest>
 				<lights type="float" userarchive="y">1.0</lights>
 				<quality-level-internal type="float" userarchive="y">1.0</quality-level-internal>
 			</shaders>