288 lines
10 KiB
GLSL
288 lines
10 KiB
GLSL
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// WS30 VERTEX SHADER
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// -*-C++-*-
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#version 120
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// Shader that uses OpenGL state values to do per-pixel lighting
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//
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// The only light used is gl_LightSource[0], which is assumed to be
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// directional.
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//
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// Colors are not assigned in this shader, as they will come from
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// the landclass lookup in the fragment shader.
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// Haze part added by Thorsten Renk, Oct. 2011
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#define MODE_OFF 0
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#define MODE_DIFFUSE 1
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#define MODE_AMBIENT_AND_DIFFUSE 2
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// From VPBTechnique.cxx
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uniform mat4 fg_zUpTransform;
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uniform vec3 fg_modelOffset;
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// The constant term of the lighting equation that doesn't depend on
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// the surface normal is passed in gl_{Front,Back}Color. The alpha
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// component is set to 1 for front, 0 for back in order to work around
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// bugs with gl_FrontFacing in the fragment shader.
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varying vec4 light_diffuse_comp;
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varying vec3 normal;
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varying vec3 relPos;
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varying vec2 ground_tex_coord;
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varying vec4 ecPosition;
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varying float yprime_alt;
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varying float mie_angle;
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// For water calculations
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varying float earthShade;
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varying vec3 lightdir;
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varying vec4 waterTex1;
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varying vec4 waterTex2;
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varying vec4 waterTex4;
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varying vec3 specular_light;
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uniform float osg_SimulationTime;
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uniform float WindN;
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uniform float WindE;
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uniform int colorMode;
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uniform float hazeLayerAltitude;
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uniform float terminator;
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uniform float terrain_alt;
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uniform float avisibility;
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uniform float visibility;
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uniform float overcast;
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uniform float ground_scattering;
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uniform float moonlight;
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uniform float eye_alt;
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void setupShadows(vec4 eyeSpacePos);
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// This is the value used in the skydome scattering shader - use the same here for consistency?
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const float EarthRadius = 5800000.0;
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const float terminator_width = 200000.0;
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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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// use the asymptotics to shorten computations
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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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void rotationmatrix(in float angle, out mat4 rotmat)
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{
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rotmat = mat4( cos( angle ), -sin( angle ), 0.0, 0.0,
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sin( angle ), cos( angle ), 0.0, 0.0,
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0.0 , 0.0 , 1.0, 0.0,
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0.0 , 0.0 , 0.0, 1.0 );
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}
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void main()
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{
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vec4 light_diffuse;
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vec4 light_ambient;
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vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
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vec3 moonLightColor = vec3 (0.095, 0.095, 0.15) * moonlight;
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//float yprime_alt;
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float yprime;
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float lightArg;
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float intensity;
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float vertex_alt;
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float scattering;
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// this code is copied from default.vert
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ecPosition = gl_ModelViewMatrix * gl_Vertex;
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gl_Position = ftransform();
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gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
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normal = gl_NormalMatrix * gl_Normal;
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// Required for water calculations
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lightdir = normalize(vec3(fg_zUpTransform * vec4(gl_ModelViewMatrixInverse * gl_LightSource[0].position)));
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waterTex4 = vec4( ecPosition.xzy, 0.0 );
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vec4 t1 = vec4(0.0, osg_SimulationTime * 0.005217, 0.0, 0.0);
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vec4 t2 = vec4(0.0, osg_SimulationTime * -0.0012, 0.0, 0.0);
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float Angle;
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float windFactor = sqrt(WindE * WindE + WindN * WindN) * 0.05;
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if (WindN == 0.0 && WindE == 0.0) {
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Angle = 0.0;
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} else {
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Angle = atan(-WindN, WindE) - atan(1.0);
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}
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mat4 RotationMatrix;
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rotationmatrix(Angle, RotationMatrix);
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waterTex1 = gl_MultiTexCoord0 * RotationMatrix - t1 * windFactor;
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rotationmatrix(Angle, RotationMatrix);
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waterTex2 = gl_MultiTexCoord0 * RotationMatrix - t2 * windFactor;
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// Temporary value:
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ground_tex_coord = gl_TexCoord[0].st;
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// here start computations for the haze layer
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// we need several geometrical quantities
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// first current altitude of eye position in model space
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vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);
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// and relative position to vector
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relPos = (fg_zUpTransform * vec4(gl_Vertex - ep)).xyz;
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// unfortunately, we need the distance in the vertex shader, although the more accurate version
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// is later computed in the fragment shader again
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float dist = length(relPos);
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// altitude of the vertex in question, somehow zero leads to artefacts, so ensure it is at least 100m
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vertex_alt = max(relPos.z + eye_alt, 100.0);
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scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, vertex_alt);
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// branch dependent on daytime
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if (terminator < 1000000.0) // the full, sunrise and sunset computation
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{
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// establish coordinates relative to sun position
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vec3 lightFull = (gl_ModelViewMatrixInverse * gl_LightSource[0].position).xyz;
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vec3 lightHorizon = normalize(vec3(lightFull.x,lightFull.y, 0.0));
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// yprime is the distance of the vertex into sun direction
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yprime = -dot(relPos, lightHorizon);
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// this gets an altitude correction, higher terrain gets to see the sun earlier
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yprime_alt = yprime - sqrt(2.0 * EarthRadius * vertex_alt);
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// two times terminator width governs how quickly light fades into shadow
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// now the light-dimming factor
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earthShade = 0.6 * (1.0 - smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt)) + 0.4;
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// parametrized version of the Flightgear ground lighting function
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lightArg = (terminator-yprime_alt)/100000.0;
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// directional scattering for low sun
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if (lightArg < 10.0) {
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mie_angle = (0.5 * dot(normalize(relPos), normalize(lightFull)) ) + 0.5;
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} else {
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mie_angle = 1.0;
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}
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light_diffuse.b = light_func(lightArg, 1.330e-05, 0.264, 3.827, 1.08e-05, 1.0);
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light_diffuse.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
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light_diffuse.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
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light_diffuse.a = 1.0;
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light_diffuse = light_diffuse * scattering;
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light_ambient.r = light_func(lightArg, 0.236, 0.253, 1.073, 0.572, 0.33);
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light_ambient.g = light_ambient.r * 0.4/0.33;
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light_ambient.b = light_ambient.r * 0.5/0.33;
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light_ambient.a = 1.0;
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// Water specular calculations
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specular_light.b = light_func(lightArg, 1.330e-05, 0.264, 3.827, 1.08e-05, 1.0);
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specular_light.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
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specular_light.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
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specular_light = max(specular_light * scattering, vec3 (0.05, 0.05, 0.05));
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intensity = length(specular_light.rgb);
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specular_light.rgb = intensity * normalize(mix(specular_light.rgb, shadedFogColor, 1.0 -smoothstep(0.1, 0.6,ground_scattering) ));
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specular_light.rgb = intensity * normalize(mix(specular_light.rgb, shadedFogColor, 1.0 -smoothstep(0.5, 0.7,earthShade)));
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// correct ambient light intensity and hue before sunrise
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if (earthShade < 0.5) {
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//light_ambient = light_ambient * (0.7 + 0.3 * smoothstep(0.2, 0.5, earthShade));
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intensity = length(light_ambient.xyz);
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light_ambient.rgb = intensity * normalize(mix(light_ambient.rgb, shadedFogColor, 1.0 -smoothstep(0.4, 0.8,earthShade) ));
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light_ambient.rgb = light_ambient.rgb + moonLightColor * (1.0 - smoothstep(0.4, 0.5, earthShade));
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intensity = length(light_diffuse.xyz);
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light_diffuse.rgb = intensity * normalize(mix(light_diffuse.rgb, shadedFogColor, 1.0 -smoothstep(0.4, 0.7,earthShade) ));
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}
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// directional scattering for low sun
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if (lightArg < 10.0) {
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mie_angle = (0.5 * dot(normalize(relPos), lightdir) ) + 0.5;
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} else {
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mie_angle = 1.0;
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}
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// the haze gets the light at the altitude of the haze top if the vertex in view is below
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// but the light at the vertex if the vertex is above
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vertex_alt = max(vertex_alt,hazeLayerAltitude);
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if (vertex_alt > hazeLayerAltitude)
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{
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if (dist > 0.8 * avisibility)
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{
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vertex_alt = mix(vertex_alt, hazeLayerAltitude, smoothstep(0.8*avisibility, avisibility, dist));
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yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
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}
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} else {
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vertex_alt = hazeLayerAltitude;
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yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
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}
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}
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else // the faster, full-day version without lightfields
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{
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earthShade = 1.0;
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mie_angle = 1.0;
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if (terminator > 3000000.0) {
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light_diffuse = vec4 (1.0, 1.0, 1.0, 0.0);
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light_ambient = vec4 (0.33, 0.4, 0.5, 0.0);
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specular_light = vec3 (1.0, 1.0, 1.0);
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} else {
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lightArg = (terminator/100000.0 - 10.0)/20.0;
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light_diffuse.b = 0.78 + lightArg * 0.21;
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light_diffuse.g = 0.907 + lightArg * 0.091;
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light_diffuse.r = 0.904 + lightArg * 0.092;
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light_diffuse.a = 1.0;
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light_ambient.r = 0.316 + lightArg * 0.016;
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light_ambient.g = light_ambient.r * 0.4/0.33;
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light_ambient.b = light_ambient.r * 0.5/0.33;
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light_ambient.a = 1.0;
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specular_light.b = 0.78 + lightArg * 0.21;
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specular_light.g = 0.907 + lightArg * 0.091;
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specular_light.r = 0.904 + lightArg * 0.092;
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}
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light_diffuse = light_diffuse * scattering;
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specular_light = specular_light * scattering;
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float shade_depth = 1.0 * smoothstep (0.6,0.95,ground_scattering) * (1.0-smoothstep(0.1,0.5,overcast)) * smoothstep(0.4,1.5,earthShade);
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specular_light.rgb *= (1.0 + 1.2 * shade_depth);
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yprime_alt = -sqrt(2.0 * EarthRadius * hazeLayerAltitude);
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}
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// default lighting based on texture and material using the light we have just computed
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light_diffuse_comp = light_diffuse;
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//Testing phase code: ambient colours are not sent to fragement shader yet.
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// They are all default except for water/ocean etc. currently
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// Emission is all set to the default of vec4(0.0, 0.0, 0.0, 1.0)
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//To do: Fix this once ambient colour becomes available in the fragment shaders.
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//const vec4 ambient_color = vec4(0.2, 0.2, 0.2, 1.0);
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vec4 constant_term = gl_LightModel.ambient + light_ambient;
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// Another hack for supporting two-sided lighting without using
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// gl_FrontFacing in the fragment shader.
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gl_FrontColor.rgb = constant_term.rgb;
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gl_BackColor.rgb = constant_term.rgb;
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gl_FrontColor.a = mie_angle;
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gl_BackColor.a = mie_angle;
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setupShadows(ecPosition);
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}
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