diff --git a/Effects/tree.eff b/Effects/tree.eff
index 3eed93b11..d6650e8ad 100644
--- a/Effects/tree.eff
+++ b/Effects/tree.eff
@@ -17,26 +17,164 @@
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ /sim/rendering/shaders/skydome
+ /sim/rendering/random-vegetation
+
+
+ 2.0
+
+
+
+ GL_ARB_shader_objects
+ GL_ARB_shading_language_100
+ GL_ARB_vertex_shader
+ GL_ARB_fragment_shader
+
+
+
+
+
+ true
+
+ 1.0 1.0 1.0 1.0
+ 1.0 1.0 1.0 1.0
+ off
+
+
+ -1
+ RenderBin
+
+
+ src-alpha
+ one-minus-src-alpha
+
+
+ 0
+ 2d
+
+
+
+ clamp
+ clamp
+
+
+
+
+ Shaders/tree.vert
+ Shaders/include_fog.frag
+ Shaders/tree.frag
+
+
+ texture
+ sampler-2d
+ 0
+
+ 0 0 0 0
+
+
+ true
+
+ 1.0 1.0 1.0 1.0
+ 1.0 1.0 1.0 1.0
+ off
+
+
+ 0
+ 2d
+
+
+
+ clamp
+ clamp
+
+
+ Shaders/tree-haze.vert
+ Shaders/tree-haze.frag
+
+
+ visibility
+ float
+
+
+
+ avisibility
+ float
+
+
+
+ hazeLayerAltitude
+ float
+
+
+
+ scattering
+ float
+
+
+
+ ground_scattering
+ float
+
+
+
+ terminator
+ float
+
+
+
+ terrain_alt
+ float
+
+
+
+ overcast
+ float
+
+
+
+ eye_alt
+ float
+
+
+
+ texture
+ sampler-2d
+ 0
+
+
+ colorMode
+ int
+ 2
+
+
+ lequal
+ false
+
+
+
+
diff --git a/Shaders/tree-haze.frag b/Shaders/tree-haze.frag
new file mode 100644
index 000000000..92c6850b5
--- /dev/null
+++ b/Shaders/tree-haze.frag
@@ -0,0 +1,288 @@
+// -*-C++-*-
+
+// written by Thorsten Renk, Oct 2011, based on default.frag
+// Ambient term comes in gl_Color.rgb.
+varying vec4 diffuse_term;
+varying vec3 normal;
+varying vec3 relPos;
+
+//varying vec3 hazeColor;
+//varying float fogCoord;
+
+uniform sampler2D texture;
+
+//varying float ct;
+//varying float delta_z;
+//varying float alt;
+
+varying float earthShade;
+//varying float yprime;
+//varying float vertex_alt;
+varying float yprime_alt;
+varying float mie_angle;
+
+
+uniform float visibility;
+uniform float avisibility;
+uniform float scattering;
+//uniform float ground_scattering;
+uniform float terminator;
+uniform float terrain_alt;
+uniform float hazeLayerAltitude;
+uniform float overcast;
+//uniform float altitude;
+uniform float eye_alt;
+
+const float EarthRadius = 5800000.0;
+const float terminator_width = 200000.0;
+
+float alt;
+
+float luminance(vec3 color)
+{
+ return dot(vec3(0.212671, 0.715160, 0.072169), color);
+}
+
+
+float light_func (in float x, in float a, in float b, in float c, in float d, in float e)
+{
+x = x - 0.5;
+
+// use the asymptotics to shorten computations
+if (x > 30.0) {return e;}
+if (x < -15.0) {return 0.0;}
+
+return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d));
+}
+
+// this determines how light is attenuated in the distance
+// physically this should be exp(-arg) but for technical reasons we use a sharper cutoff
+// for distance > visibility
+
+float fog_func (in float targ)
+{
+
+
+float fade_mix;
+
+// for large altitude > 30 km, we switch to some component of quadratic distance fading to
+// create the illusion of improved visibility range
+
+targ = 1.25 * targ; // need to sync with the distance to which terrain is drawn
+
+
+if (alt < 30000.0)
+ {return exp(-targ - targ * targ * targ * targ);}
+else if (alt < 50000.0)
+ {
+ fade_mix = (alt - 30000.0)/20000.0;
+ return fade_mix * exp(-targ*targ - pow(targ,4.0)) + (1.0 - fade_mix) * exp(-targ - pow(targ,4.0));
+ }
+else
+ {
+ return exp(- targ * targ - pow(targ,4.0));
+ }
+
+}
+
+void main()
+{
+
+// this is taken from default.frag
+ vec3 n;
+ float NdotL, NdotHV, fogFactor;
+ vec4 color = gl_Color;
+ vec3 lightDir = gl_LightSource[0].position.xyz;
+ vec3 halfVector = gl_LightSource[0].halfVector.xyz;
+ vec4 texel;
+ vec4 fragColor;
+ vec4 specular = vec4(0.0);
+ float intensity;
+
+
+
+ vec4 light_specular = gl_LightSource[0].specular;
+
+ // If gl_Color.a == 0, this is a back-facing polygon and the
+ // normal should be reversed.
+ n = (2.0 * gl_Color.a - 1.0) * normal;
+ n = normalize(n);
+
+ NdotL = dot(n, lightDir);
+ if (NdotL > 0.0) {
+ color += diffuse_term * NdotL;
+ NdotHV = max(dot(n, halfVector), 0.0);
+ if (gl_FrontMaterial.shininess > 0.0)
+ specular.rgb = (gl_FrontMaterial.specular.rgb
+ * light_specular.rgb
+ * pow(NdotHV, gl_FrontMaterial.shininess));
+ }
+ color.a = diffuse_term.a;
+ // This shouldn't be necessary, but our lighting becomes very
+ // saturated. Clamping the color before modulating by the texture
+ // is closer to what the OpenGL fixed function pipeline does.
+ color = clamp(color, 0.0, 1.0);
+ texel = texture2D(texture, gl_TexCoord[0].st);
+
+ fragColor = color * texel + specular;
+
+
+
+// here comes the terrain haze model
+
+
+float delta_z = hazeLayerAltitude - eye_alt;
+float dist = length(relPos);
+
+
+if (dist > 40.0)
+{
+
+alt = eye_alt;
+
+
+float transmission;
+float vAltitude;
+float delta_zv;
+float H;
+float distance_in_layer;
+float transmission_arg;
+
+// angle with horizon
+float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
+
+
+// we solve the geometry what part of the light path is attenuated normally and what is through the haze layer
+
+if (delta_z > 0.0) // we're inside the layer
+ {
+ if (ct < 0.0) // we look down
+ {
+ distance_in_layer = dist;
+ vAltitude = min(distance_in_layer,min(visibility, avisibility)) * ct;
+ delta_zv = delta_z - vAltitude;
+ }
+ else // we may look through upper layer edge
+ {
+ H = dist * ct;
+ if (H > delta_z) {distance_in_layer = dist/H * delta_z;}
+ else {distance_in_layer = dist;}
+ vAltitude = min(distance_in_layer,visibility) * ct;
+ delta_zv = delta_z - vAltitude;
+ }
+ }
+ else // we see the layer from above, delta_z < 0.0
+ {
+ H = dist * -ct;
+ if (H < (-delta_z)) // we don't see into the layer at all, aloft visibility is the only fading
+ {
+ distance_in_layer = 0.0;
+ delta_zv = 0.0;
+ }
+ else
+ {
+ vAltitude = H + delta_z;
+ distance_in_layer = vAltitude/H * dist;
+ vAltitude = min(distance_in_layer,visibility) * (-ct);
+ delta_zv = vAltitude;
+ }
+ }
+
+
+// ground haze cannot be thinner than aloft visibility in the model,
+// so we need to use aloft visibility otherwise
+
+
+transmission_arg = (dist-distance_in_layer)/avisibility;
+
+
+float eqColorFactor;
+
+//float scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, relPos.z + eye_alt);
+
+if (visibility < avisibility)
+ {
+ transmission_arg = transmission_arg + (distance_in_layer/visibility);
+ // this combines the Weber-Fechner intensity
+ eqColorFactor = 1.0 - 0.1 * delta_zv/visibility - (1.0 -scattering);
+
+ }
+else
+ {
+ transmission_arg = transmission_arg + (distance_in_layer/avisibility);
+ // this combines the Weber-Fechner intensity
+ eqColorFactor = 1.0 - 0.1 * delta_zv/avisibility - (1.0 -scattering);
+ }
+
+
+
+transmission = fog_func(transmission_arg);
+
+// there's always residual intensity, we should never be driven to zero
+if (eqColorFactor < 0.2) eqColorFactor = 0.2;
+
+
+float lightArg = (terminator-yprime_alt)/100000.0;
+
+vec3 hazeColor;
+
+hazeColor.b = light_func(lightArg, 1.330e-05, 0.264, 2.527, 1.08e-05, 1.0);
+hazeColor.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
+hazeColor.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
+
+
+// now dim the light for haze
+float eShade = earthShade;
+eShade = 0.9 * smoothstep(terminator_width+ terminator, -terminator_width + terminator, yprime_alt) + 0.1;
+
+// Mie-like factor
+
+if (lightArg < 10.0)
+ {intensity = length(hazeColor);
+ float mie_magnitude = 0.5 * smoothstep(350000.0, 150000.0, terminator-sqrt(2.0 * EarthRadius * terrain_alt));
+ hazeColor = intensity * ((1.0 - mie_magnitude) + mie_magnitude * mie_angle) * normalize(mix(hazeColor, vec3 (0.5, 0.58, 0.65), mie_magnitude * (0.5 - 0.5 * mie_angle)) );
+ }
+
+// high altitude desaturation of the haze color
+
+intensity = length(hazeColor);
+hazeColor = intensity * normalize (mix(hazeColor, intensity * vec3 (1.0,1.0,1.0), 0.7* smoothstep(5000.0, 50000.0, alt)));
+
+// blue hue of haze
+
+hazeColor.x = hazeColor.x * 0.83;
+hazeColor.y = hazeColor.y * 0.9;
+
+
+// additional blue in indirect light
+float fade_out = max(0.65 - 0.3 *overcast, 0.45);
+intensity = length(hazeColor);
+hazeColor = intensity * normalize(mix(hazeColor, 1.5* vec3 (0.45, 0.6, 0.8), 1.0 -smoothstep(0.25, fade_out,eShade) ));
+
+// change haze color to blue hue for strong fogging
+//intensity = length(hazeColor);
+hazeColor = intensity * normalize(mix(hazeColor, 2.0 * vec3 (0.55, 0.6, 0.8), (1.0-smoothstep(0.3,0.8,eqColorFactor))));
+
+
+// reduce haze intensity when looking at shaded surfaces, only in terminator region
+
+float shadow = mix( min(1.0 + dot(normal,lightDir),1.0), 1.0, 1.0-smoothstep(0.1, 0.4, transmission));
+hazeColor = mix(shadow * hazeColor, hazeColor, 0.3 + 0.7* smoothstep(250000.0, 400000.0, terminator));
+
+
+// determine the right mix of transmission and haze
+
+//fragColor.xyz = transmission * fragColor.xyz + (1.0-transmission) * eqColorFactor * hazeColor * earthShade;
+
+fragColor.xyz = mix(eqColorFactor * hazeColor * eShade, fragColor.xyz,transmission);
+
+gl_FragColor = fragColor;
+
+}
+else // if dist < 40.0 no fogging at all
+{
+gl_FragColor = fragColor;
+}
+
+}
+
diff --git a/Shaders/tree-haze.vert b/Shaders/tree-haze.vert
new file mode 100644
index 000000000..222e3828e
--- /dev/null
+++ b/Shaders/tree-haze.vert
@@ -0,0 +1,245 @@
+// -*-C++-*-
+
+// Shader that uses OpenGL state values to do per-pixel lighting
+//
+// The only light used is gl_LightSource[0], which is assumed to be
+// directional.
+//
+// Diffuse colors come from the gl_Color, ambient from the material. This is
+// equivalent to osg::Material::DIFFUSE.
+// Haze part added by Thorsten Renk, Oct. 2011
+
+
+#define MODE_OFF 0
+#define MODE_DIFFUSE 1
+#define MODE_AMBIENT_AND_DIFFUSE 2
+
+// The constant term of the lighting equation that doesn't depend on
+// the surface normal is passed in gl_{Front,Back}Color. The alpha
+// component is set to 1 for front, 0 for back in order to work around
+// bugs with gl_FrontFacing in the fragment shader.
+varying vec4 diffuse_term;
+varying vec3 normal;
+varying vec3 relPos;
+
+varying float earthShade;
+//varying float yprime;
+//varying float vertex_alt;
+varying float yprime_alt;
+varying float mie_angle;
+
+
+
+
+uniform int colorMode;
+uniform float hazeLayerAltitude;
+uniform float terminator;
+uniform float terrain_alt;
+uniform float avisibility;
+uniform float visibility;
+uniform float overcast;
+//uniform float scattering;
+uniform float ground_scattering;
+
+
+// This is the value used in the skydome scattering shader - use the same here for consistency?
+const float EarthRadius = 5800000.0;
+const float terminator_width = 200000.0;
+
+float light_func (in float x, in float a, in float b, in float c, in float d, in float e)
+{
+//x = x - 0.5;
+
+// use the asymptotics to shorten computations
+if (x < -15.0) {return 0.0;}
+
+return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d));
+}
+
+
+void main()
+{
+
+ vec4 light_diffuse;
+ vec4 light_ambient;
+
+ //float yprime_alt;
+ float yprime;
+ float lightArg;
+ float intensity;
+ float vertex_alt;
+ float scattering;
+
+// this code is copied from tree.vert
+
+ float numVarieties = gl_Normal.z;
+ float texFract = floor(fract(gl_MultiTexCoord0.x) * numVarieties) / numVarieties;
+ texFract += floor(gl_MultiTexCoord0.x) / numVarieties;
+ float sr = sin(gl_FogCoord);
+ float cr = cos(gl_FogCoord);
+ gl_TexCoord[0] = vec4(texFract, gl_MultiTexCoord0.y, 0.0, 0.0);
+
+ // scaling
+ vec3 position = gl_Vertex.xyz * gl_Normal.xxy;
+
+ // Rotation of the generic quad to specific one for the tree.
+ position.xy = vec2(dot(position.xy, vec2(cr, sr)), dot(position.xy, vec2(-sr, cr)));
+ position = position + gl_Color.xyz;
+ gl_Position = gl_ModelViewProjectionMatrix * vec4(position,1.0);
+
+ vec3 ecPosition = vec3(gl_ModelViewMatrix * vec4(position, 1.0));
+ normal = normalize(-ecPosition);
+
+ float n = dot(normalize(gl_LightSource[0].position.xyz), normalize(-ecPosition));
+
+
+ vec4 diffuse_color = gl_FrontMaterial.diffuse * max(0.1, n);
+ //diffuse_color.a = 1.0;
+ vec4 ambient_color = gl_FrontLightModelProduct.sceneColor + gl_LightSource[0].ambient * gl_FrontMaterial.ambient;
+
+ // here start computations for the haze layer
+ // we need several geometrical quantities
+
+ // first current altitude of eye position in model space
+ vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);
+
+ // and relative position to vector
+ relPos = position - ep.xyz;
+
+ // unfortunately, we need the distance in the vertex shader, although the more accurate version
+ // is later computed in the fragment shader again
+ float dist = length(relPos);
+
+ // altitude of the vertex in question, somehow zero leads to artefacts, so ensure it is at least 100m
+ vertex_alt = max(position.z,100.0);
+ scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, vertex_alt);
+
+ // branch dependent on daytime
+
+if (terminator < 1000000.0) // the full, sunrise and sunset computation
+{
+
+
+ // establish coordinates relative to sun position
+
+ vec3 lightFull = (gl_ModelViewMatrixInverse * gl_LightSource[0].position).xyz;
+ vec3 lightHorizon = normalize(vec3(lightFull.x,lightFull.y, 0.0));
+
+
+
+ // yprime is the distance of the vertex into sun direction
+ yprime = -dot(relPos, lightHorizon);
+
+ // this gets an altitude correction, higher terrain gets to see the sun earlier
+ yprime_alt = yprime - sqrt(2.0 * EarthRadius * vertex_alt);
+
+ // two times terminator width governs how quickly light fades into shadow
+ // now the light-dimming factor
+ earthShade = 0.6 * (1.0 - smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt)) + 0.4;
+
+ // parametrized version of the Flightgear ground lighting function
+ lightArg = (terminator-yprime_alt)/100000.0;
+
+ // directional scattering for low sun
+ if (lightArg < 10.0)
+ {mie_angle = (0.5 * dot(normalize(relPos), normalize(lightFull)) ) + 0.5;}
+ else
+ {mie_angle = 1.0;}
+
+
+
+
+ light_diffuse.b = light_func(lightArg, 1.330e-05, 0.264, 3.827, 1.08e-05, 1.0);
+ light_diffuse.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
+ light_diffuse.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
+ light_diffuse.a = 0.0;
+ light_diffuse = light_diffuse * scattering;
+
+ light_ambient.b = light_func(lightArg, 0.000506, 0.131, -3.315, 0.000457, 0.5);
+ light_ambient.g = light_func(lightArg, 2.264e-05, 0.134, 0.967, 3.66e-05, 0.4);
+ light_ambient.r = light_func(lightArg, 0.236, 0.253, 1.073, 0.572, 0.33);
+ light_ambient.a = 0.0;
+
+
+
+
+// correct ambient light intensity and hue before sunrise
+if (earthShade < 0.5)
+ {
+ light_ambient = light_ambient * (0.4 + 0.6 * smoothstep(0.2, 0.5, earthShade));
+ intensity = length(light_ambient.xyz);
+
+ light_ambient.xyz = intensity * normalize(mix(light_ambient.xyz, vec3 (0.45, 0.6, 0.8), 1.0 -smoothstep(0.1, 0.5,earthShade) ));
+
+ intensity = length(light_diffuse.xyz);
+ light_diffuse.xyz = intensity * normalize(mix(light_diffuse.xyz, vec3 (0.45, 0.6, 0.8), 1.0 -smoothstep(0.1, 0.5,earthShade) ));
+ }
+
+
+// the haze gets the light at the altitude of the haze top if the vertex in view is below
+// but the light at the vertex if the vertex is above
+
+vertex_alt = max(vertex_alt,hazeLayerAltitude);
+
+if (vertex_alt > hazeLayerAltitude)
+ {
+ if (dist > 0.8 * avisibility)
+ {
+ vertex_alt = mix(vertex_alt, hazeLayerAltitude, smoothstep(0.8*avisibility, avisibility, dist));
+ yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
+ }
+ }
+else
+ {
+ vertex_alt = hazeLayerAltitude;
+ yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
+ }
+
+}
+else // the faster, full-day version without lightfields
+{
+ //vertex_alt = max(gl_Vertex.z,100.0);
+
+ earthShade = 1.0;
+ mie_angle = 1.0;
+
+ if (terminator > 3000000.0)
+ {light_diffuse = vec4 (1.0, 1.0, 1.0, 0.0);
+ light_ambient = vec4 (0.33, 0.4, 0.5, 0.0); }
+ else
+ {
+
+ lightArg = (terminator/100000.0 - 10.0)/20.0;
+ light_diffuse.b = 0.78 + lightArg * 0.21;
+ light_diffuse.g = 0.907 + lightArg * 0.091;
+ light_diffuse.r = 0.904 + lightArg * 0.092;
+ light_diffuse.a = 0.0;
+
+ light_ambient.b = 0.41 + lightArg * 0.08;
+ light_ambient.g = 0.333 + lightArg * 0.06;
+ light_ambient.r = 0.316 + lightArg * 0.016;
+ light_ambient.a = 0.0;
+ }
+
+ light_diffuse = light_diffuse * scattering;
+ yprime_alt = -sqrt(2.0 * EarthRadius * hazeLayerAltitude);
+}
+
+
+// default lighting based on texture and material using the light we have just computed
+
+ diffuse_term = diffuse_color* light_diffuse;
+ vec4 constant_term = gl_FrontMaterial.emission + ambient_color *
+ (gl_LightModel.ambient + light_ambient);
+ // Super hack: if diffuse material alpha is less than 1, assume a
+ // transparency animation is at work
+ if (gl_FrontMaterial.diffuse.a < 1.0)
+ diffuse_term.a = gl_FrontMaterial.diffuse.a;
+ else
+ diffuse_term.a = gl_Color.a;
+ // Another hack for supporting two-sided lighting without using
+ // gl_FrontFacing in the fragment shader.
+ gl_FrontColor.rgb = constant_term.rgb; gl_FrontColor.a = 1.0;
+ gl_BackColor.rgb = constant_term.rgb; gl_BackColor.a = 0.0;
+}
+