494 lines
14 KiB
C++
494 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 ecViewdir;
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uniform sampler2D texture;
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uniform sampler2D NormalTex;
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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 rain_norm;
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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 uvstretch;
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uniform float landing_light1_offset;
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uniform float landing_light2_offset;
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uniform float air_pollution;
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uniform float osg_SimulationTime;
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uniform int quality_level;
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uniform int tquality_level;
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uniform int cloud_shadow_flag;
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uniform int use_searchlight;
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uniform int use_landing_light;
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uniform int use_alt_landing_light;
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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 shadow_func (in float x, in float y, in float noise, in float dist);
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float Noise2D(in vec2 coord, in float wavelength);
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float DotNoise2D(in vec2 coord, in float wavelength, in float fractionalMaxDotSize, in float dot_density);
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float fog_func (in float targ, in float alt);
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float light_distance_fading(in float dist);
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float fog_backscatter(in float avisibility);
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float rayleigh_in_func(in float dist, in float air_pollution, in float avisibility, in float eye_alt, in float vertex_alt);
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vec3 searchlight();
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vec3 landing_light(in float offset);
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float light_func (in float x, in float a, in float b, in float c, in float d, in float e)
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{
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x = x - 0.5;
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// use the asymptotics to shorten computations
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if (x > 30.0) {return e;}
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if (x < -15.0) {return 0.0;}
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return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d));
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}
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// this determines how light is attenuated in the distance
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// physically this should be exp(-arg) but for technical reasons we use a sharper cutoff
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// for distance > visibility
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void main()
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{
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yprime_alt = diffuse_term.a;
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mie_angle = gl_Color.a;
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float effective_scattering = 1.0 - 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(0.65, 0.67, 0.78);
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// this is taken from default.frag
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vec3 n;
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float NdotL, NdotHV;
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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 E = normalize(ecViewdir);
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vec3 halfVector;
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if (quality_level<6)
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{halfVector = gl_LightSource[0].halfVector.xyz;}
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else
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{halfVector = normalize(normalize(lightDir) + E);}
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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_01m;
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float noise_1m = Noise2D(rawPos.xy, 1.0);
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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;
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float noise_500m = Noise2D(rawPos.xy, 500.0);
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float noise_1500m = Noise2D(rawPos.xy, 1500.0);
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float noise_2000m = Noise2D(rawPos.xy, 2000.0);
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//
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// get the texels
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texel = texture2D(texture, vec2 (gl_TexCoord[0].s, gl_TexCoord[0].t * uvstretch));
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vec4 nmap = texture2D(NormalTex, gl_TexCoord[0].st * 8.0);
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vec3 N = nmap.rgb * 2.0 - 1.0;
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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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if (quality_level > 3)
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{
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float sfactor;
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noise_01m = Noise2D(rawPos.xy,0.1);
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snow_texel = vec4 (0.95, 0.95, 0.95, 1.0) * (0.9 + 0.1* noise_50m + 0.1* (1.0 - noise_10m) );
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snow_texel.a = 1.0;
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noise_term = 0.1 * (noise_50m-0.5);
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sfactor = 1.0;//sqrt(2.0 * (1.0-steepness)/0.03) + abs(ct)/0.15;
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noise_term = noise_term + 0.2 * (noise_10m -0.5) * (1.0 - smoothstep(10000.0*sfactor, 16000.0*sfactor, dist) ) ;
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noise_term = noise_term + 0.3 * (noise_5m -0.5) * (1.0 - smoothstep(1200.0 * sfactor, 2000.0 * sfactor, dist) ) ;
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noise_term = noise_term + 0.3 * (noise_1m -0.5) * (1.0 - smoothstep(500.0 * sfactor, 1000.0 *sfactor, dist) );
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noise_term = noise_term + 0.3 * (noise_01m -0.5) * (1.0 - smoothstep(20.0 * sfactor, 100.0 *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 + 0.2*snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
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}
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const vec3 dust_color = vec3 (0.76, 0.71, 0.56);
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const vec3 lichen_color = vec3 (0.17, 0.20, 0.06);
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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.rgb = mix(texel.rgb, 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.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) );
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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.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));
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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 , 0.5 * (noise_5m + (1.0 -noise_1m))) * (1.0 - smoothstep(1000.0, 3000.0, dist));
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}
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// darken wet terrain
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texel.rgb = texel.rgb * (1.0 - 0.6 * wetness - 0.1 * water_factor);
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// light computations
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eShade = 1.0 - 0.9 * smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt);
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vec4 light_specular = gl_LightSource[0].specular * eShade;
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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 = normal;
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n = normalize(n);
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// primary reflection of the Sun
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float fresnel;
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NdotL = dot(n, lightDir);
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if (quality_level > 4)
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{
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NdotL = NdotL + (3.0 * N.r + 0.1 * (noise_01m-0.5))* (1.0 - water_factor) ;
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}
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if (NdotL > 0.0)
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{
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if (cloud_shadow_flag == 1)
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{NdotL = NdotL * shadow_func(relPos.x, relPos.y, 1.0, dist);}
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color += diffuse_term * NdotL;
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NdotHV = max(dot(n, halfVector), 0.0);
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fresnel = 1.0 + 5.0 * (1.0-smoothstep(0.0,0.2, dot(E,n)));
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specular.rgb = ((vec3 (0.2,0.2,0.2) * fresnel + (water_factor * vec3 (1.0, 1.0, 1.0)))
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* light_specular.rgb
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* pow(NdotHV, max(4.0, (20.0 * water_factor))));
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}
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// raindrops
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float rain_factor = 0.0;
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if (rain_norm > 0.0)
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{
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rain_factor += DotNoise2D(rawPos.xy, 0.2 ,0.5, rain_norm) * abs(sin(6.0*osg_SimulationTime));
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rain_factor += DotNoise2D(rawPos.xy, 0.3 ,0.4, rain_norm) * abs(sin(6.0*osg_SimulationTime + 2.094));
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rain_factor += DotNoise2D(rawPos.xy, 0.4 ,0.3, rain_norm)* abs(sin(6.0*osg_SimulationTime + 4.188));
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}
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// secondary reflection of sky irradiance
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float fresnelW = ((0.8 * wetness) + (0.2* water_factor)) * (1.0-smoothstep(0.0,0.4, dot(E,n) * 1.0 - 0.2 * rain_factor * wetness));
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float sky_factor = (1.0-ct*ct);//mix((1.0 - ct * ct), 1.0-effective_scattering, effective_scattering);
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vec3 sky_light = vec3 (1.0,1.0,1.0) * length(light_specular.rgb) * (1.0-effective_scattering);
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specular.rgb += sky_factor * fresnelW * sky_light;
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//specular.rgb *= 1.0 - 0.2 * dotnoise_02m * wetness;
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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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vec3 secondary_light = vec3 (0.0,0.0,0.0);
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if (use_searchlight == 1)
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{
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secondary_light.rgb += searchlight();
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}
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if (use_landing_light == 1)
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{
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secondary_light += landing_light(landing_light1_offset);
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}
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if (use_alt_landing_light == 1)
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{
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secondary_light += landing_light(landing_light2_offset);
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}
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color.rgb +=secondary_light * light_distance_fading(dist);
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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 - 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 - 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;
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hazeColor.b = light_func(lightArg, 1.330e-05, 0.264, 2.527, 1.08e-05, 1.0);
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hazeColor.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
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hazeColor.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
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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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}
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hazeColor = clamp(hazeColor, 0.0, 1.0);
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// blue Rayleigh scattering with distance
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float rShade = 0.9 * smoothstep(terminator_width+ terminator, -terminator_width + terminator, yprime_alt-340000.0) + 0.1;
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float lightIntensity = length(diffuse_term.rgb)/1.73 * rShade;
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vec3 rayleighColor = vec3 (0.17, 0.52, 0.87) * lightIntensity;
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float rayleighStrength = rayleigh_in_func(dist, air_pollution, avisibility/max(lightIntensity,0.05), eye_alt, eye_alt + relPos.z);
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if ((quality_level>5) && (tquality_level>5))
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{
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fragColor.rgb = mix(fragColor.rgb, rayleighColor,rayleighStrength);
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}
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fragColor.rgb = mix((eqColorFactor * hazeColor * eShade)+secondary_light * fog_backscatter(avisibility), fragColor.rgb,transmission);
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|
|
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gl_FragColor = fragColor;
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|
|
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}
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else // if dist < threshold no fogging at all
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{
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// blue Rayleigh scattering with distance
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|
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float rShade = 0.9 * smoothstep(terminator_width+ terminator, -terminator_width + terminator, yprime_alt-340000.0) + 0.1;
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float lightIntensity = length(diffuse_term.rgb)/1.73 * rShade;
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vec3 rayleighColor = vec3 (0.17, 0.52, 0.87) * lightIntensity;
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float rayleighStrength = rayleigh_in_func(dist, air_pollution, avisibility/max(lightIntensity,0.05), eye_alt, eye_alt + relPos.z);
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if ((quality_level>5) && (tquality_level>5))
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{
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fragColor.rgb = mix(fragColor.rgb, rayleighColor,rayleighStrength);
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}
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gl_FragColor = fragColor;
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}
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}
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