557 lines
16 KiB
C
557 lines
16 KiB
C
// -*- mode: C; -*-
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// Licence: GPL v2
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// Author: Frederic Bouvier.
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// Adapted from the paper by F. Policarpo et al. : Real-time Relief Mapping on Arbitrary Polygonal Surfaces
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// Adapted from the paper and sources by M. Drobot in GPU Pro : Quadtree Displacement Mapping with Height Blending
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#version 120
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#extension GL_ATI_shader_texture_lod : enable
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#extension GL_ARB_shader_texture_lod : enable
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#define TEXTURE_MIP_LEVELS 10
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#define TEXTURE_PIX_COUNT 1024 //pow(2,TEXTURE_MIP_LEVELS)
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#define BINARY_SEARCH_COUNT 10
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#define BILINEAR_SMOOTH_FACTOR 2.0
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varying vec3 worldPos;
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varying vec4 ecPosition;
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varying vec3 VNormal;
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varying vec3 VTangent;
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varying vec4 constantColor;
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varying vec3 light_diffuse;
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varying vec3 relPos;
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varying float yprime_alt;
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varying float mie_angle;
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uniform sampler2D BaseTex;
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uniform sampler2D NormalTex;
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uniform sampler2D QDMTex;
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uniform float depth_factor;
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uniform float tile_size;
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uniform float quality_level;
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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 mysnowlevel;
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uniform float dust_cover_factor;
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uniform float wetness;
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uniform float fogstructure;
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uniform float cloud_self_shading;
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uniform float air_pollution;
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uniform float landing_light1_offset;
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uniform float landing_light2_offset;
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uniform vec3 night_color;
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uniform bool random_buildings;
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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 scale = 1.0;
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int linear_search_steps = 10;
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int GlobalIterationCount = 0;
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int gIterationCap = 64;
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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 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 Noise3D(in vec3 coord, in float wavelength);
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float fog_func (in float targ, in float alt);
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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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float alt_factor(in float eye_alt, in float vertex_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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vec3 rayleigh_out_shift(in vec3 color, in float outscatter);
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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 QDM(inout vec3 p, inout vec3 v)
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{
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const int MAX_LEVEL = TEXTURE_MIP_LEVELS;
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const float NODE_COUNT = TEXTURE_PIX_COUNT;
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const float TEXEL_SPAN_HALF = 1.0 / NODE_COUNT / 2.0;
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float fDeltaNC = TEXEL_SPAN_HALF * depth_factor;
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vec3 p2 = p;
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float level = MAX_LEVEL;
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vec2 dirSign = (sign(v.xy) + 1.0) * 0.5;
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GlobalIterationCount = 0;
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float d = 0.0;
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while (level >= 0.0 && GlobalIterationCount < gIterationCap)
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{
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vec4 uv = vec4(p2.xyz, level);
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d = texture2DLod(QDMTex, uv.xy, uv.w).w;
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if (d > p2.z)
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{
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//predictive point of ray traversal
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vec3 tmpP2 = p + v * d;
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//current node count
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float nodeCount = pow(2.0, (MAX_LEVEL - level));
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//current and predictive node ID
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vec4 nodeID = floor(vec4(p2.xy, tmpP2.xy)*nodeCount);
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//check if we are crossing the current cell
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if (nodeID.x != nodeID.z || nodeID.y != nodeID.w)
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{
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//calculate distance to nearest bound
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vec2 a = p2.xy - p.xy;
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vec2 p3 = (nodeID.xy + dirSign) / nodeCount;
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vec2 b = p3.xy - p.xy;
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vec2 dNC = (b.xy * p2.z) / a.xy;
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//take the nearest cell
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d = min(d,min(dNC.x, dNC.y))+fDeltaNC;
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level++;
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}
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p2 = p + v * d;
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}
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level--;
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GlobalIterationCount++;
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}
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//
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// Manual Bilinear filtering
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//
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float rayLength = length(p2.xy - p.xy) + fDeltaNC;
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float dA = p2.z * (rayLength - BILINEAR_SMOOTH_FACTOR * TEXEL_SPAN_HALF) / rayLength;
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float dB = p2.z * (rayLength + BILINEAR_SMOOTH_FACTOR * TEXEL_SPAN_HALF) / rayLength;
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vec4 p2a = vec4(p + v * dA, 0.0);
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vec4 p2b = vec4(p + v * dB, 0.0);
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dA = texture2DLod(NormalTex, p2a.xy, p2a.w).w;
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dB = texture2DLod(NormalTex, p2b.xy, p2b.w).w;
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dA = abs(p2a.z - dA);
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dB = abs(p2b.z - dB);
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p2 = mix(p2a.xyz, p2b.xyz, dA / (dA + dB));
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p = p2;
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}
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float ray_intersect_QDM(vec2 dp, vec2 ds)
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{
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vec3 p = vec3( dp, 0.0 );
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vec3 v = vec3( ds, 1.0 );
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QDM( p, v );
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return p.z;
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}
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float ray_intersect_relief(vec2 dp, vec2 ds)
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{
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float size = 1.0 / float(linear_search_steps);
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float depth = 0.0;
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float best_depth = 1.0;
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for(int i = 0; i < linear_search_steps - 1; ++i)
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{
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depth += size;
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float t = step(0.95, texture2D(NormalTex, dp + ds * depth).a);
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if(best_depth > 0.996)
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if(depth >= t)
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best_depth = depth;
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}
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depth = best_depth;
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const int binary_search_steps = 5;
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for(int i = 0; i < binary_search_steps; ++i)
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{
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size *= 0.5;
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float t = step(0.95, texture2D(NormalTex, dp + ds * depth).a);
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if(depth >= t)
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{
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best_depth = depth;
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depth -= 2.0 * size;
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}
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depth += size;
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}
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return(best_depth);
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}
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float ray_intersect(vec2 dp, vec2 ds)
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{
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if ( random_buildings )
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return 0.0;
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else if ( quality_level >= 4.0 )
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return ray_intersect_QDM( dp, ds );
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else
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return ray_intersect_relief( dp, ds );
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}
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void main (void)
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{
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if ( quality_level >= 3.0 ) {
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linear_search_steps = 20;
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}
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float depthfactor = depth_factor;
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if ( random_buildings )
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depthfactor = 0.0;
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vec3 shadedFogColor = vec3(0.65, 0.67, 0.78);
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float effective_scattering = min(scattering, cloud_self_shading);
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vec3 normal = normalize(VNormal);
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vec3 tangent = normalize(VTangent);
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//vec3 binormal = normalize(VBinormal);
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vec3 binormal = normalize(cross(normal, tangent));
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vec3 ecPos3 = ecPosition.xyz / ecPosition.w;
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vec3 V = normalize(ecPos3);
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vec3 s = vec3(dot(V, tangent), dot(V, binormal), dot(normal, -V));
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vec2 ds = s.xy * depthfactor / s.z;
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vec2 dp = gl_TexCoord[0].st - ds;
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float d = ray_intersect(dp, ds);
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vec2 uv = dp + ds * d;
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vec3 N = texture2D(NormalTex, uv).xyz * 2.0 - 1.0;
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float emis = N.z;
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N.z = sqrt(1.0 - min(1.0,dot(N.xy, N.xy)));
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float Nz = N.z;
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N = normalize(N.x * tangent + N.y * binormal + N.z * normal);
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vec3 l = gl_LightSource[0].position.xyz;
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vec3 diffuse = gl_Color.rgb * max(0.0, dot(N, l));
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float dist = length(relPos);
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if (cloud_shadow_flag == 1)
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{diffuse = diffuse * shadow_func(relPos.x, relPos.y, 1.0, dist);}
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float shadow_factor = 1.0;
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// Shadow
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if ( quality_level >= 2.0 ) {
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dp += ds * d;
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vec3 sl = normalize( vec3( dot( l, tangent ), dot( l, binormal ), dot( -l, normal ) ) );
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ds = sl.xy * depthfactor / sl.z;
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dp -= ds * d;
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float dl = ray_intersect(dp, ds);
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if ( dl < d - 0.05 )
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shadow_factor = dot( constantColor.xyz, vec3( 1.0, 1.0, 1.0 ) ) * 0.25;
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}
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// end shadow
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vec4 ambient_light = constantColor + vec4 (light_diffuse,1.0) * vec4(diffuse, 1.0);
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float reflectance = ambient_light.r * 0.3 + ambient_light.g * 0.59 + ambient_light.b * 0.11;
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if ( shadow_factor < 1.0 )
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ambient_light = constantColor + vec4(light_diffuse,1.0) * shadow_factor * vec4(diffuse, 1.0);
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float emission_factor = (1.0 - smoothstep(0.15, 0.25, reflectance)) * emis;
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vec4 tc = texture2D(BaseTex, uv);
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emission_factor *= 0.5*pow(tc.r+0.8*tc.g+0.2*tc.b, 2.0) -0.2;
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ambient_light += (emission_factor * vec4(night_color, 0.0));
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vec4 finalColor = texture2D(BaseTex, uv);
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// texel postprocessing by shader effects
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// dust effect
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vec4 dust_color;
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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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if (quality_level > 2)
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{
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// mix dust
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dust_color = vec4 (0.76, 0.71, 0.56, 1.0);
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finalColor = mix(finalColor, 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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}
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// darken wet terrain
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finalColor.rgb = finalColor.rgb * (1.0 - 0.6 * wetness);
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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 += 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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ambient_light = clamp(ambient_light,0.0,1.0);
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ambient_light.rgb +=secondary_light * light_distance_fading(dist);
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finalColor *= ambient_light;
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vec4 p = vec4( ecPos3 + tile_size * V * (d-1.0) * depthfactor / s.z, 1.0 );
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// Rayleigh color shift due to out-scattering
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float rayleigh_length = 0.5 * avisibility * (2.5 - 1.9 * air_pollution)/alt_factor(eye_alt, eye_alt+relPos.z);
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float outscatter = 1.0-exp(-dist/rayleigh_length);
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finalColor.rgb = rayleigh_out_shift(finalColor.rgb,outscatter);
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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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{
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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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float intensity;
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vec3 lightDir = gl_LightSource[0].position.xyz;
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// angle with horizon
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float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
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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;
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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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// now dim the light for haze
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eShade = 0.9 * smoothstep(terminator_width+ terminator, -terminator_width + terminator, yprime_alt) + 0.1;
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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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// Mie-like factor
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if (lightArg < 10.0)
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{
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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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// 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(VNormal,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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// 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(light_diffuse.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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finalColor.rgb = mix(finalColor.rgb, rayleighColor,rayleighStrength);
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finalColor.rgb = mix((eqColorFactor * hazeColor * eShade) +secondary_light * fog_backscatter(avisibility), finalColor.rgb,transmission);
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gl_FragColor = finalColor;
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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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float rShade = 0.9 * smoothstep(terminator_width+ terminator, -terminator_width + terminator, yprime_alt-340000.0) + 0.1;
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float lightIntensity = length(light_diffuse.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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finalColor.rgb = mix(finalColor.rgb, rayleighColor,rayleighStrength);
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gl_FragColor = finalColor;
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}
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// gl_FragColor = finalColor;
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if (dot(normal,-V) > 0.1) {
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vec4 iproj = gl_ProjectionMatrix * p;
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iproj /= iproj.w;
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gl_FragDepth = (iproj.z+1.0)/2.0;
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} else {
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gl_FragDepth = gl_FragCoord.z;
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}
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}
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