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High quality dirt runway effect for ALS

This commit is contained in:
Thorsten Renk 2014-01-23 13:16:20 +02:00
parent 49d9da2af0
commit aae72d7266
4 changed files with 759 additions and 1 deletions

254
Effects/dirt-runway.eff Normal file
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<?xml version="1.0" encoding="utf-8"?>
<PropertyList>
<name>Effects/dirt-runway</name>
<inherits-from>Effects/runway</inherits-from>
<parameters>
<texture n="16">
<image>Textures.high/Terrain/sand_hires_ochre.png</image>
<type>2d</type>
<filter>linear-mipmap-linear</filter>
<wrap-s>repeat</wrap-s>
<wrap-t>repeat</wrap-t>
<internal-format>normalized</internal-format>
</texture>
<texture n="17">
<image>Textures.high/Terrain/airport_grass2.png</image>
<type>2d</type>
<filter>linear-mipmap-linear</filter>
<wrap-s>repeat</wrap-s>
<wrap-t>repeat</wrap-t>
<internal-format>normalized</internal-format>
</texture>
</parameters>
<technique n="2">
<predicate>
<and>
<property>/sim/rendering/shaders/skydome</property>
<or>
<less-equal>
<value type="float">4.0</value>
<float-property>/sim/rendering/shaders/landmass</float-property>
</less-equal>
<less-equal>
<value type="float">3.0</value>
<float-property>/sim/rendering/shaders/transition</float-property>
</less-equal>
</or>
<or>
<less-equal>
<value type="float">2.0</value>
<glversion/>
</less-equal>
<and>
<extension-supported>GL_ARB_shader_objects</extension-supported>
<extension-supported>GL_ARB_shading_language_100</extension-supported>
<extension-supported>GL_ARB_vertex_shader</extension-supported>
<extension-supported>GL_ARB_fragment_shader</extension-supported>
</and>
</or>
</and>
</predicate>
<pass>
<lighting>true</lighting>
<material>
<ambient><use>material/ambient</use></ambient>
<diffuse><use>material/diffuse</use></diffuse>
<specular><use>material/specular</use></specular>
<emissive><use>material/emissive</use></emissive>
<shininess><use>material/shininess</use></shininess>
<color-mode>ambient-and-diffuse</color-mode>
</material>
<blend><use>transparent</use></blend>
<alpha-test><use>transparent</use></alpha-test>
<shade-model>smooth</shade-model>
<cull-face>back</cull-face>
<render-bin>
<bin-number><use>render-bin/bin-number</use></bin-number>
<bin-name><use>render-bin/bin-name</use></bin-name>
</render-bin>
<texture-unit>
<unit>0</unit>
<type><use>texture[16]/type</use></type>
<image><use>texture[16]/image</use></image>
<filter><use>texture[16]/filter</use></filter>
<wrap-s><use>texture[16]/wrap-s</use></wrap-s>
<wrap-t><use>texture[16]/wrap-t</use></wrap-t>
<internal-format><use>texture[16]/internal-format</use></internal-format>
</texture-unit>
<texture-unit>
<unit>4</unit>
<type><use>texture[4]/type</use></type>
<image><use>texture[4]/image</use></image>
<filter><use>texture[4]/filter</use></filter>
<wrap-s><use>texture[4]/wrap-s</use></wrap-s>
<wrap-t><use>texture[4]/wrap-t</use></wrap-t>
<internal-format><use>texture[4]/internal-format</use></internal-format>
</texture-unit>
<texture-unit>
<unit>5</unit>
<type><use>texture[17]/type</use></type>
<image><use>texture[17]/image</use></image>
<filter><use>texture[17]/filter</use></filter>
<wrap-s><use>texture[17]/wrap-s</use></wrap-s>
<wrap-t><use>texture[17]/wrap-t</use></wrap-t>
<internal-format><use>texture[17]/internal-format</use></internal-format>
</texture-unit>
<texture-unit>
<unit>6</unit>
<type><use>texture[10]/type</use></type>
<image><use>texture[10]/image</use></image>
<filter><use>texture[10]/filter</use></filter>
<wrap-s><use>texture[10]/wrap-s</use></wrap-s>
<wrap-t><use>texture[10]/wrap-t</use></wrap-t>
<internal-format><use>texture[10]/internal-format</use></internal-format>
</texture-unit>
<texture-unit>
<unit>7</unit>
<type><use>texture[11]/type</use></type>
<image><use>texture[11]/image</use></image>
<filter><use>texture[11]/filter</use></filter>
<wrap-s><use>texture[11]/wrap-s</use></wrap-s>
<wrap-t><use>texture[11]/wrap-t</use></wrap-t>
<internal-format><use>texture[11]/internal-format</use></internal-format>
</texture-unit>
<program>
<vertex-shader>Shaders/terrain-haze-ultra.vert</vertex-shader>
<fragment-shader>Shaders/drunway-lightfield.frag</fragment-shader>
</program>
<uniform>
<name>visibility</name>
<type>float</type>
<value><use>visibility</use></value>
</uniform>
<uniform>
<name>avisibility</name>
<type>float</type>
<value><use>avisibility</use></value>
</uniform>
<uniform>
<name>hazeLayerAltitude</name>
<type>float</type>
<value><use>lthickness</use></value>
</uniform>
<uniform>
<name>scattering</name>
<type>float</type>
<value><use>scattering</use></value>
</uniform>
<uniform>
<name>ground_scattering</name>
<type>float</type>
<value><use>ground_scattering</use></value>
</uniform>
<uniform>
<name>terminator</name>
<type>float</type>
<value><use>terminator</use></value>
</uniform>
<uniform>
<name>terrain_alt</name>
<type>float</type>
<value><use>terrain_alt</use></value>
</uniform>
<uniform>
<name>overcast</name>
<type>float</type>
<value><use>overcast</use></value>
</uniform>
<uniform>
<name>eye_alt</name>
<type>float</type>
<value><use>eye_alt</use></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>
<uniform>
<name>dust_cover_factor</name>
<type>float</type>
<value><use>dust_cover_factor</use></value>
</uniform>
<uniform>
<name>lichen_cover_factor</name>
<type>float</type>
<value> <use>lichen_cover_factor</use></value>
</uniform>
<uniform>
<name>wetness</name>
<type>float</type>
<value><use>wetness</use></value>
</uniform>
<uniform>
<name>fogstructure</name>
<type>float</type>
<value><use>fogstructure</use></value>
</uniform>
<uniform>
<name>cloud_self_shading</name>
<type>float</type>
<value><use>cloud_self_shading</use></value>
</uniform>
<uniform>
<name>moonlight</name>
<type>float</type>
<value><use>moonlight</use></value>
</uniform>
<uniform>
<name>quality_level</name>
<type>int</type>
<value><use>quality_level</use></value>
</uniform>
<uniform>
<name>tquality_level</name>
<type>int</type>
<value><use>tquality_level</use></value>
</uniform>
<uniform>
<name>texture</name>
<type>sampler-2d</type>
<value type="int">0</value>
</uniform>
<uniform>
<name>NormalTex</name>
<type>sampler-2d</type>
<value type="int">4</value>
</uniform>
<uniform>
<name>mix_texture</name>
<type>sampler-2d</type>
<value type="int">5</value>
</uniform>
<uniform>
<name>snow_texture</name>
<type>sampler-2d</type>
<value type="int">6</value>
</uniform>
<uniform>
<name>detail_texture</name>
<type>sampler-2d</type>
<value type="int">7</value>
</uniform>
<uniform>
<name>colorMode</name>
<type>int</type>
<value>2</value>
<!-- AMBIENT_AND_DIFFUSE -->
</uniform>
<depth>
<function>lequal</function>
<!-- <write-mask type="bool">false</write-mask> -->
</depth>
</pass>
</technique>
</PropertyList>

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@ -18,6 +18,7 @@
<material>
<name>dirt_rwy</name>
<effect>Effects/dirt-runway</effect>
<texture>Runway/dirt_rwy.png</texture>
<friction-factor>0.7</friction-factor>
<rolling-friction>0.04</rolling-friction>

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// -*-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 vec2 nvec;
varying vec3 relPos;
varying vec2 rawPos;
varying vec3 ecViewdir;
uniform sampler2D texture;
uniform sampler2D NormalTex;
//uniform sampler3D NoiseTex;
//uniform sampler2D snow_texture;
//uniform sampler2D detail_texture;
uniform sampler2D mix_texture;
//varying float yprime_alt;
//varying float mie_angle;
varying float steepness;
uniform float visibility;
uniform float avisibility;
uniform float scattering;
uniform float terminator;
uniform float terrain_alt;
uniform float hazeLayerAltitude;
uniform float overcast;
uniform float eye_alt;
uniform float snowlevel;
uniform float dust_cover_factor;
uniform float lichen_cover_factor;
uniform float wetness;
uniform float fogstructure;
uniform float snow_thickness_factor;
uniform float cloud_self_shading;
uniform int quality_level;
uniform int tquality_level;
const float EarthRadius = 5800000.0;
const float terminator_width = 200000.0;
float alt;
float eShade;
float yprime_alt;
float mie_angle;
float rand2D(in vec2 co){
return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 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);
//return mix(a,b,x);
}
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 Noise2D(in vec2 coord, in float wavelength)
{
return interpolatedNoise2D(coord.x/wavelength, coord.y/wavelength);
}
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 * smoothstep(0.04,0.06,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()
{
yprime_alt = diffuse_term.a;
//diffuse_term.a = 1.0;
mie_angle = gl_Color.a;
float effective_scattering = min(scattering, cloud_self_shading);
// distance to fragment
float dist = length(relPos);
// angle of view vector with horizon
float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
vec3 shadedFogColor = vec3(0.65, 0.67, 0.78);
// this is taken from default.frag
vec3 n;
float NdotL, NdotHV, fogFactor;
vec4 color = gl_Color;
color.a = 1.0;
vec3 lightDir = gl_LightSource[0].position.xyz;
vec3 halfVector;
if (quality_level<6)
{halfVector = gl_LightSource[0].halfVector.xyz;}
else
{halfVector = normalize(normalize(lightDir) + normalize(ecViewdir));}
vec4 texel;
vec4 snow_texel;
vec4 detail_texel;
vec4 mix_texel;
vec4 fragColor;
vec4 specular = vec4(0.0);
float intensity;
// get noise at different wavelengths
// used: 5m, 5m gradient, 10m, 10m gradient: heightmap of the closeup terrain, 10m also snow
// 50m: detail texel
// 250m: detail texel
// 500m: distortion and overlay
// 1500m: overlay, detail, dust, fog
// 2000m: overlay, detail, snow, fog
float noise_01m;
float noise_1m = Noise2D(rawPos.xy, 1.0);
float noise_10m;
float noise_5m;
noise_10m = Noise2D(rawPos.xy, 10.0);
noise_5m = Noise2D(rawPos.xy ,5.0);
float noisegrad_10m;
float noisegrad_5m;
float noise_50m = Noise2D(rawPos.xy, 50.0);;
float noise_250m;
float noise_500m = Noise2D(rawPos.xy, 500.0);
float noise_1500m = Noise2D(rawPos.xy, 1500.0);
float noise_2000m = Noise2D(rawPos.xy, 2000.0);
//
// get the texels
texel = texture2D(texture, gl_TexCoord[0].st);
mix_texel = texture2D(mix_texture, gl_TexCoord[0].st * 5.0);
vec4 nmap = texture2D(NormalTex, gl_TexCoord[0].st * 8.0);
vec3 N = nmap.rgb * 2.0 - 1.0;
float distortion_factor = 1.0;
vec2 stprime;
int flag = 1;
int mix_flag = 1;
float noise_term;
float snow_alpha;
noise_term = smoothstep(0.8,1.0,noise_1m);
texel = mix(texel, mix_texel, noise_term);
//float view_angle = abs(dot(normal, normalize(ecViewdir)));
//if ((quality_level > 3)&&(relPos.z + eye_alt +500.0 > snowlevel))
if (quality_level > 3)
{
float sfactor;
noise_01m = Noise2D(rawPos.xy,0.1);
snow_texel = vec4 (0.95, 0.95, 0.95, 1.0) * (0.9 + 0.1* noise_50m + 0.1* (1.0 - noise_10m) );
snow_texel.a = 1.0;
noise_term = 0.1 * (noise_50m-0.5);
sfactor = 1.0;//sqrt(2.0 * (1.0-steepness)/0.03) + abs(ct)/0.15;
noise_term = noise_term + 0.2 * (noise_10m -0.5) * (1.0 - smoothstep(10000.0*sfactor, 16000.0*sfactor, dist) ) ;
noise_term = noise_term + 0.3 * (noise_5m -0.5) * (1.0 - smoothstep(1200.0 * sfactor, 2000.0 * sfactor, dist) ) ;
noise_term = noise_term + 0.3 * (noise_1m -0.5) * (1.0 - smoothstep(500.0 * sfactor, 1000.0 *sfactor, dist) );
noise_term = noise_term + 0.3 * (noise_01m -0.5) * (1.0 - smoothstep(20.0 * sfactor, 100.0 *sfactor, dist) );
snow_texel.a = snow_texel.a * 0.2+0.8* smoothstep(0.2,0.8, 0.3 +noise_term + 0.2*snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
}
const vec4 dust_color = vec4 (0.76, 0.71, 0.56, 1.0);
const vec4 lichen_color = vec4 (0.17, 0.20, 0.06, 1.0);;
//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)) );
// 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) );
// 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));
}
}
// get distribution of water when terrain is wet
float water_threshold1;
float water_threshold2;
float water_factor =0.0;
if ((dist < 5000.0)&& (quality_level > 3) && (wetness>0.0))
{
water_threshold1 = 1.0-0.5* wetness;
water_threshold2 = 1.0 - 0.3 * wetness;
//water_factor = smoothstep(water_threshold1, water_threshold2 , (0.3 * (2.0 * (1.0-noise_10m) + (1.0 -noise_5m)) * (1.0 - smoothstep(2000.0, 5000.0, dist))) - 5.0 * (1.0 -steepness));
water_factor = smoothstep(water_threshold1, water_threshold2 , 0.5 * (noise_5m + (1.0 -noise_1m))) * (1.0 - smoothstep(1000.0, 3000.0, dist));
}
// darken wet terrain
texel.rgb = texel.rgb * (1.0 - 0.6 * wetness - 0.1 * water_factor);
// light computations
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 = normal;//vec3 (nvec.x, nvec.y, sqrt(1.0 -pow(nvec.x,2.0) - pow(nvec.y,2.0) ));
n = normalize(n);
NdotL = dot(n, lightDir);
if (quality_level > 4)
{
NdotL = NdotL + (3.0 * N.r + 0.1 * (noise_01m-0.5))* (1.0 - water_factor) ;
//NdotL = NdotL + 3.0 * N.r + 0.1 * (noise_01m-0.5) ;
}
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 + (water_factor * vec3 (1.0, 1.0, 1.0)))
* light_specular.rgb
* pow(NdotHV, gl_FrontMaterial.shininess + (20.0 * water_factor)));
}
color.a = 1.0;//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);
fragColor = color * texel + specular;
// here comes the terrain haze model
float delta_z = hazeLayerAltitude - eye_alt;
if (dist > 0.04 * min(visibility,avisibility))
//if ((gl_FragCoord.y > ylimit) || (gl_FragCoord.x < zlimit1) || (gl_FragCoord.x > zlimit2))
//if (dist > 40.0)
{
alt = eye_alt;
float transmission;
float vAltitude;
float delta_zv;
float H;
float distance_in_layer;
float transmission_arg;
// 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;
if (visibility < avisibility)
{
if (quality_level > 3)
{
transmission_arg = transmission_arg + (distance_in_layer/(1.0 * visibility + 1.0 * visibility * fogstructure * 0.06 * (noise_1500m + noise_2000m -1.0) ));
}
else
{
transmission_arg = transmission_arg + (distance_in_layer/visibility);
}
// this combines the Weber-Fechner intensity
eqColorFactor = 1.0 - 0.1 * delta_zv/visibility - (1.0 - effective_scattering);
}
else
{
if (quality_level > 3)
{
transmission_arg = transmission_arg + (distance_in_layer/(1.0 * avisibility + 1.0 * avisibility * fogstructure * 0.06 * (noise_1500m + noise_2000m - 1.0) ));
}
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 - effective_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
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)) );
}
intensity = length(hazeColor);
if (intensity > 0.0) // this needs to be a condition, because otherwise hazeColor doesn't come out correctly
{
// high altitude desaturation of the haze color
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* shadedFogColor, 1.0 -smoothstep(0.25, fade_out,eShade) ));
// change haze color to blue hue for strong fogging
hazeColor = intensity * normalize(mix(hazeColor, shadedFogColor, (1.0-smoothstep(0.5,0.9,eqColorFactor))));
// reduce haze intensity when looking at shaded surfaces, only in terminator region
float shadow = mix( min(1.0 + dot(n,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));
}
fragColor.rgb = mix(eqColorFactor * hazeColor * eShade , fragColor.rgb,transmission);
gl_FragColor = fragColor;
}
else // if dist < threshold no fogging at all
{
gl_FragColor = fragColor;
}
}

View file

@ -224,7 +224,8 @@ float noise_2000m = Noise2D(rawPos.xy, 2000.0);
//float view_angle = abs(dot(normal, normalize(ecViewdir)));
if ((quality_level > 3)&&(relPos.z + eye_alt +500.0 > snowlevel))
//if ((quality_level > 3)&&(relPos.z + eye_alt +500.0 > snowlevel))
if (quality_level > 3)
{
float sfactor;
noise_01m = Noise2D(rawPos.xy,0.1);