501 lines
14 KiB
C++
501 lines
14 KiB
C++
// -*-C++-*-
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// written by Thorsten Renk, Oct 2011, based on default.frag
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// Ambient term comes in gl_Color.rgb.
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varying vec4 diffuse_term;
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varying vec3 normal;
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varying vec3 relPos;
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varying vec2 rawPos;
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varying vec3 worldPos;
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uniform sampler2D texture;
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uniform sampler2D detail_texture;
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uniform sampler2D mix_texture;
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//varying float yprime_alt;
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//varying float mie_angle;
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varying float steepness;
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uniform float visibility;
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uniform float avisibility;
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uniform float scattering;
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uniform float terminator;
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uniform float terrain_alt;
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uniform float hazeLayerAltitude;
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uniform float overcast;
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uniform float eye_alt;
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uniform float snowlevel;
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uniform float dust_cover_factor;
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uniform float lichen_cover_factor;
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uniform float wetness;
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uniform float fogstructure;
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uniform float snow_thickness_factor;
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uniform float cloud_self_shading;
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uniform float season;
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uniform float transition_model;
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uniform float hires_overlay_bias;
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uniform int quality_level;
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uniform int tquality_level;
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const float EarthRadius = 5800000.0;
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const float terminator_width = 200000.0;
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float alt;
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float eShade;
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float yprime_alt;
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float mie_angle;
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float Noise2D(in vec2 coord, in float wavelength);
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float Noise3D(in vec3 coord, in float wavelength);
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float fog_func (in float targ, in float alt);
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vec3 get_hazeColor(in float light_arg);
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void main()
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{
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yprime_alt = diffuse_term.a;
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//diffuse_term.a = 1.0;
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mie_angle = gl_Color.a;
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float effective_scattering = min(scattering, cloud_self_shading);
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// distance to fragment
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float dist = length(relPos);
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// angle of view vector with horizon
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float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
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vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
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// this is taken from default.frag
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vec3 n;
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float NdotL, NdotHV, fogFactor;
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vec4 color = gl_Color;
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color.a = 1.0;
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vec3 lightDir = gl_LightSource[0].position.xyz;
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vec3 halfVector = gl_LightSource[0].halfVector.xyz;
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//vec3 halfVector = normalize(normalize(lightDir) + normalize(ecViewdir));
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vec4 texel;
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vec4 snow_texel;
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vec4 detail_texel;
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vec4 mix_texel;
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vec4 fragColor;
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vec4 specular = vec4(0.0);
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float intensity;
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// get noise at different wavelengths
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// used: 5m, 5m gradient, 10m, 10m gradient: heightmap of the closeup terrain, 10m also snow
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// 50m: detail texel
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// 250m: detail texel
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// 500m: distortion and overlay
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// 1500m: overlay, detail, dust, fog
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// 2000m: overlay, detail, snow, fog
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float noise_10m;
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float noise_5m;
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noise_10m = Noise2D(rawPos.xy, 10.0);
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noise_5m = Noise2D(rawPos.xy ,5.0);
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float noisegrad_10m;
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float noisegrad_5m;
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float noise_50m = Noise2D(rawPos.xy, 50.0);;
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float noise_250m = Noise3D(worldPos.xyz,250.0);
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float noise_500m = Noise3D(worldPos.xyz, 500.0);
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float noise_1500m = Noise3D(worldPos.xyz, 1500.0);
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float noise_2000m = Noise3D(worldPos.xyz, 2000.0);
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//
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// get the texels
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texel = texture2D(texture, gl_TexCoord[0].st);
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float local_autumn_factor = texel.a;
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float distortion_factor = 1.0;
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vec2 stprime;
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int flag = 1;
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int mix_flag = 1;
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float noise_term;
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float snow_alpha;
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//float view_angle = abs(dot(normal, normalize(ecViewdir)));
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if ((quality_level > 3)&&(relPos.z + eye_alt +500.0 > snowlevel))
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{
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float sfactor;
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snow_texel = vec4 (0.95, 0.95, 0.95, 1.0) * (0.9 + 0.1* noise_500m + 0.1* (1.0 - noise_10m) );
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snow_texel.r = snow_texel.r * (0.9 + 0.05 * (noise_10m + noise_5m));
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snow_texel.g = snow_texel.g * (0.9 + 0.05 * (noise_10m + noise_5m));
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snow_texel.a = 1.0;
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noise_term = 0.1 * (noise_500m-0.5);
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sfactor = sqrt(2.0 * (1.0-steepness)/0.03) + abs(ct)/0.15;
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noise_term = noise_term + 0.2 * (noise_50m -0.5) * (1.0 - smoothstep(18000.0*sfactor, 40000.0*sfactor, dist) ) ;
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noise_term = noise_term + 0.3 * (noise_10m -0.5) * (1.0 - smoothstep(4000.0 * sfactor, 8000.0 * sfactor, dist) ) ;
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if (dist < 3000.0*sfactor){ noise_term = noise_term + 0.3 * (noise_5m -0.5) * (1.0 - smoothstep(1000.0 * sfactor, 3000.0 *sfactor, dist) );}
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snow_texel.a = snow_texel.a * 0.2+0.8* smoothstep(0.2,0.8, 0.3 +noise_term + snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
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}
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if (tquality_level > 2)
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{
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mix_texel = texture2D(mix_texture, gl_TexCoord[0].st * 1.3);
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if (mix_texel.a <0.1) {mix_flag = 0;}
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}
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if (tquality_level > 3)
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{
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stprime = vec2 (0.86*gl_TexCoord[0].s + 0.5*gl_TexCoord[0].t, 0.5*gl_TexCoord[0].s - 0.86*gl_TexCoord[0].t);
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//distortion_factor = 0.9375 + (1.0 * nvL[2]);
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distortion_factor = 0.97 + 0.06 * noise_500m;
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stprime = stprime * distortion_factor * 15.0;
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if (quality_level > 4)
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{
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stprime = stprime + normalize(relPos).xy * 0.02 * (noise_10m + 0.5 * noise_5m - 0.75);
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}
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detail_texel = texture2D(detail_texture, stprime);
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if (detail_texel.a <0.1) {flag = 0;}
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}
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// texture preparation according to detail level
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// mix in hires texture patches
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float dist_fact;
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float nSum;
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float mix_factor;
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if (tquality_level > 2)
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{
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// first the second texture overlay
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// transition model 0: random patch overlay without any gradient information
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// transition model 1: only gradient-driven transitions, no randomness
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if (mix_flag == 1)
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{
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nSum = 0.18 * (2.0 * noise_2000m + 2.0 * noise_1500m + noise_500m);
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nSum = mix(nSum, 0.5, max(0.0, 2.0 * (transition_model - 0.5)));
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nSum = nSum + 0.4 * (1.0 -smoothstep(0.9,0.95, abs(steepness)+ 0.05 * (noise_50m - 0.5))) * min(1.0, 2.0 * transition_model);
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mix_factor = smoothstep(0.5, 0.54, nSum);
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texel = mix(texel, mix_texel, mix_factor);
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local_autumn_factor = texel.a;
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}
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// then the detail texture overlay
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}
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if (tquality_level > 3)
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{
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if (dist < 40000.0)
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{
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if (flag == 1)
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{
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//noise_50m = Noise2D(rawPos.xy, 50.0);
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//noise_250m = Noise2D(rawPos.xy, 250.0);
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dist_fact = 0.1 * smoothstep(15000.0,40000.0, dist) - 0.03 * (1.0 - smoothstep(500.0,5000.0, dist));
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nSum = ((1.0 -noise_2000m) + noise_1500m + 2.0 * noise_250m +noise_50m)/5.0;
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nSum = nSum - 0.08 * (1.0 -smoothstep(0.9,0.95, abs(steepness)));
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mix_factor = smoothstep(0.47, 0.54, nSum +hires_overlay_bias - dist_fact);
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if (mix_factor > 0.8) {mix_factor = 0.8;}
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texel = mix(texel, detail_texel,mix_factor);
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local_autumn_factor = texel.a;
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}
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}
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}
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// autumn colors
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float autumn_factor = season * 2.0 * (1.0 - local_autumn_factor) ;
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texel.r = min(1.0, (1.0 + 2.5 * autumn_factor) * texel.r);
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texel.g = texel.g;
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texel.b = max(0.0, (1.0 - 4.0 * autumn_factor) * texel.b);
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if (local_autumn_factor < 1.0)
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{
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intensity = length(texel.rgb) * (1.0 - 0.5 * smoothstep(1.1,2.0,season));
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texel.rgb = intensity * normalize(mix(texel.rgb, vec3(0.23,0.17,0.08), smoothstep(1.1,2.0, season)));
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}
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const vec4 dust_color = vec4 (0.76, 0.71, 0.56, 1.0);
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const vec4 lichen_color = vec4 (0.17, 0.20, 0.06, 1.0);;
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//float snow_alpha;
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if (quality_level > 3)
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{
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// mix vegetation
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texel = mix(texel, lichen_color, 0.4 * lichen_cover_factor + 0.8 * lichen_cover_factor * 0.5 * (noise_10m + (1.0 - noise_5m)) );
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// mix dust
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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) );
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// mix snow
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if (relPos.z + eye_alt +500.0 > snowlevel)
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{
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snow_alpha = smoothstep(0.75, 0.85, abs(steepness));
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//texel = mix(texel, snow_texel, texel_snow_fraction);
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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));
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}
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}
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// get distribution of water when terrain is wet
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float water_threshold1;
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float water_threshold2;
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float water_factor =0.0;
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if ((dist < 5000.0)&& (quality_level > 3) && (wetness>0.0))
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{
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water_threshold1 = 1.0-0.5* wetness;
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water_threshold2 = 1.0 - 0.3 * wetness;
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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));
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}
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// darken wet terrain
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texel.rgb = texel.rgb * (1.0 - 0.6 * wetness);
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// light computations
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vec4 light_specular = gl_LightSource[0].specular;
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// If gl_Color.a == 0, this is a back-facing polygon and the
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// normal should be reversed.
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//n = (2.0 * gl_Color.a - 1.0) * normal;
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n = normal;//vec3 (nvec.x, nvec.y, sqrt(1.0 -pow(nvec.x,2.0) - pow(nvec.y,2.0) ));
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n = normalize(n);
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NdotL = dot(n, lightDir);
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if ((tquality_level > 3) && (mix_flag ==1)&& (dist < 2000.0) && (quality_level > 4))
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{
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noisegrad_10m = (noise_10m - Noise2D(rawPos.xy+ 0.05 * normalize(lightDir.xy),10.0))/0.05;
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noisegrad_5m = (noise_5m - Noise2D(rawPos.xy+ 0.05 * normalize(lightDir.xy),5.0))/0.05;
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NdotL = NdotL + 1.0 * (noisegrad_10m + 0.5* noisegrad_5m) * mix_factor/0.8 * (1.0 - smoothstep(1000.0, 2000.0, dist));
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}
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if (NdotL > 0.0) {
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color += diffuse_term * NdotL;
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NdotHV = max(dot(n, halfVector), 0.0);
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if (gl_FrontMaterial.shininess > 0.0)
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specular.rgb = ((gl_FrontMaterial.specular.rgb * 0.1 + (water_factor * vec3 (1.0, 1.0, 1.0)))
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* light_specular.rgb
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* pow(NdotHV, gl_FrontMaterial.shininess + (20.0 * water_factor)));
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}
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color.a = 1.0;//diffuse_term.a;
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// This shouldn't be necessary, but our lighting becomes very
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// saturated. Clamping the color before modulating by the texture
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// is closer to what the OpenGL fixed function pipeline does.
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color = clamp(color, 0.0, 1.0);
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fragColor = color * texel + specular;
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// here comes the terrain haze model
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float delta_z = hazeLayerAltitude - eye_alt;
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if (dist > 0.04 * min(visibility,avisibility))
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//if ((gl_FragCoord.y > ylimit) || (gl_FragCoord.x < zlimit1) || (gl_FragCoord.x > zlimit2))
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//if (dist > 40.0)
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{
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alt = eye_alt;
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float transmission;
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float vAltitude;
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float delta_zv;
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float H;
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float distance_in_layer;
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float transmission_arg;
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// we solve the geometry what part of the light path is attenuated normally and what is through the haze layer
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if (delta_z > 0.0) // we're inside the layer
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{
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if (ct < 0.0) // we look down
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{
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distance_in_layer = dist;
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vAltitude = min(distance_in_layer,min(visibility, avisibility)) * ct;
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delta_zv = delta_z - vAltitude;
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}
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else // we may look through upper layer edge
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{
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H = dist * ct;
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if (H > delta_z) {distance_in_layer = dist/H * delta_z;}
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else {distance_in_layer = dist;}
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vAltitude = min(distance_in_layer,visibility) * ct;
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delta_zv = delta_z - vAltitude;
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}
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}
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else // we see the layer from above, delta_z < 0.0
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{
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H = dist * -ct;
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if (H < (-delta_z)) // we don't see into the layer at all, aloft visibility is the only fading
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{
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distance_in_layer = 0.0;
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delta_zv = 0.0;
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}
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else
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{
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vAltitude = H + delta_z;
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distance_in_layer = vAltitude/H * dist;
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vAltitude = min(distance_in_layer,visibility) * (-ct);
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delta_zv = vAltitude;
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}
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}
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// ground haze cannot be thinner than aloft visibility in the model,
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// so we need to use aloft visibility otherwise
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transmission_arg = (dist-distance_in_layer)/avisibility;
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float eqColorFactor;
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if (visibility < avisibility)
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{
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if (quality_level > 3)
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{
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transmission_arg = transmission_arg + (distance_in_layer/(1.0 * visibility + 1.0 * visibility * fogstructure * 0.06 * (noise_1500m + noise_2000m -1.0) ));
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}
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else
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{
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transmission_arg = transmission_arg + (distance_in_layer/visibility);
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}
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// this combines the Weber-Fechner intensity
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eqColorFactor = 1.0 - 0.1 * delta_zv/visibility - (1.0 - effective_scattering);
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}
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else
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{
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if (quality_level > 3)
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{
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transmission_arg = transmission_arg + (distance_in_layer/(1.0 * avisibility + 1.0 * avisibility * fogstructure * 0.06 * (noise_1500m + noise_2000m - 1.0) ));
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}
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else
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{
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transmission_arg = transmission_arg + (distance_in_layer/avisibility);
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}
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// this combines the Weber-Fechner intensity
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eqColorFactor = 1.0 - 0.1 * delta_zv/avisibility - (1.0 - effective_scattering);
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}
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transmission = fog_func(transmission_arg, alt);
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// there's always residual intensity, we should never be driven to zero
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if (eqColorFactor < 0.2) eqColorFactor = 0.2;
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float lightArg = (terminator-yprime_alt)/100000.0;
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vec3 hazeColor = get_hazeColor(lightArg);
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// now dim the light for haze
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eShade = 1.0 - 0.9 * smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt);
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// Mie-like factor
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if (lightArg < 10.0)
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{
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intensity = length(hazeColor);
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float mie_magnitude = 0.5 * smoothstep(350000.0, 150000.0, terminator-sqrt(2.0 * EarthRadius * terrain_alt));
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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)) );
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}
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intensity = length(hazeColor);
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if (intensity > 0.0) // this needs to be a condition, because otherwise hazeColor doesn't come out correctly
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{
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// high altitude desaturation of the haze color
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hazeColor = intensity * normalize (mix(hazeColor, intensity * vec3 (1.0,1.0,1.0), 0.7* smoothstep(5000.0, 50000.0, alt)));
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// blue hue of haze
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hazeColor.x = hazeColor.x * 0.83;
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hazeColor.y = hazeColor.y * 0.9;
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// additional blue in indirect light
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float fade_out = max(0.65 - 0.3 *overcast, 0.45);
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intensity = length(hazeColor);
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hazeColor = intensity * normalize(mix(hazeColor, 1.5* shadedFogColor, 1.0 -smoothstep(0.25, fade_out,eShade) ));
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// change haze color to blue hue for strong fogging
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hazeColor = intensity * normalize(mix(hazeColor, shadedFogColor, (1.0-smoothstep(0.5,0.9,eqColorFactor))));
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// reduce haze intensity when looking at shaded surfaces, only in terminator region
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float shadow = mix( min(1.0 + dot(n,lightDir),1.0), 1.0, 1.0-smoothstep(0.1, 0.4, transmission));
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hazeColor = mix(shadow * hazeColor, hazeColor, 0.3 + 0.7* smoothstep(250000.0, 400000.0, terminator));
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// don't let the light fade out too rapidly
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lightArg = (terminator + 200000.0)/100000.0;
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float minLightIntensity = min(0.2,0.16 * lightArg + 0.5);
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vec3 minLight = minLightIntensity * vec3 (0.2, 0.3, 0.4);
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hazeColor *= eqColorFactor * eShade;
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hazeColor.rgb = max(hazeColor.rgb, minLight.rgb);
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}
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fragColor.rgb = mix(clamp(hazeColor,0.0,1.0) , clamp(fragColor.rgb,0.0,1.0),transmission);
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}
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gl_FragColor = fragColor;
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}
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