443 lines
13 KiB
GLSL
443 lines
13 KiB
GLSL
// This shader is mostly an adaptation of the shader found at
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// http://www.bonzaisoftware.com/water_tut.html and its glsl conversion
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// available at http://forum.bonzaisoftware.com/viewthread.php?tid=10
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// © Michael Horsch - 2005
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// Major update and revisions - 2011-10-07
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// © Emilian Huminiuc and Vivian Meazza
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// Optimisation - 2012-5-05
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// © Emilian Huminiuc and Vivian Meazza
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// Ported to the Atmospheric Light Scattering Framework
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// by Thorsten Renk, Aug. 2013
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#version 120
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#define fps2kts 0.5925
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uniform sampler2D water_normalmap;
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uniform sampler2D water_reflection;
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uniform sampler2D water_dudvmap;
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uniform sampler2D water_reflection_grey;
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uniform sampler2D sea_foam;
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uniform sampler2D alpha_tex;
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uniform sampler2D bowwave_nmap;
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uniform float saturation, Overcast, WindE, WindN, spd, hdg;
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uniform float CloudCover0, CloudCover1, CloudCover2, CloudCover3, CloudCover4;
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uniform int Status;
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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 scattering;
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uniform float ground_scattering;
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uniform float cloud_self_shading;
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uniform float eye_alt;
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uniform float fogstructure;
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uniform float ice_cover;
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uniform float sea_r;
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uniform float sea_g;
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uniform float sea_b;
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uniform int quality_level;
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varying vec4 waterTex1; //moving texcoords
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varying vec4 waterTex2; //moving texcoords
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varying vec3 viewerdir;
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varying vec3 lightdir;
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varying vec3 normal;
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varying vec3 relPos;
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varying float earthShade;
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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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vec3 specular_light;
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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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const float terminator_width = 200000.0;
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const float EarthRadius = 5800000.0;
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/////// functions /////////
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float normalize_range(float _val)
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{
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if (_val > 180.0)
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return _val - 360.0;
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else
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return _val;
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}
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void relWind(out float rel_wind_speed_kts, out float rel_wind_from_rad)
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{
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//calculate the carrier speed north and east in kts
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float speed_north_kts = cos(radians(hdg)) * spd ;
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float speed_east_kts = sin(radians(hdg)) * spd ;
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//calculate the relative wind speed north and east in kts
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float rel_wind_speed_from_east_kts = WindE*fps2kts + speed_east_kts;
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float rel_wind_speed_from_north_kts = WindN*fps2kts + speed_north_kts;
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//combine relative speeds north and east to get relative windspeed in kts
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rel_wind_speed_kts = sqrt(rel_wind_speed_from_east_kts*rel_wind_speed_from_east_kts
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+ rel_wind_speed_from_north_kts*rel_wind_speed_from_north_kts);
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//calculate the relative wind direction
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float rel_wind_from_deg = degrees(atan(rel_wind_speed_from_east_kts, rel_wind_speed_from_north_kts));
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// rel_wind_from_rad = atan(rel_wind_speed_from_east_kts, rel_wind_speed_from_north_kts);
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float rel_wind = rel_wind_from_deg - hdg;
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rel_wind = normalize_range(rel_wind);
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rel_wind_from_rad = radians(rel_wind);
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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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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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//////////////////////
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void main(void)
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{
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const vec4 sca = vec4(0.005, 0.005, 0.005, 0.005);
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const vec4 sca2 = vec4(0.02, 0.02, 0.02, 0.02);
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const vec4 tscale = vec4(0.25, 0.25, 0.25, 0.25);
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mat4 RotationMatrix;
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float relWindspd=0;
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float relWinddir=0;
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float dist = length(relPos);
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vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
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float effective_scattering = min(scattering, cloud_self_shading);
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// compute relative wind speed and direction
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relWind (relWindspd, relWinddir);
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rotationmatrix(relWinddir, RotationMatrix);
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// compute direction to viewer
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vec3 E = normalize(viewerdir);
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// compute direction to light source
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vec3 L = normalize(lightdir);
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// half vector
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vec3 H = normalize(L + E);
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const float water_shininess = 240.0;
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// approximate cloud cover
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float cover = 0.0;
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//bool Status = true;
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float windEffect = relWindspd; //wind speed in kt
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// float windEffect = sqrt(pow(abs(WindE),2)+pow(abs(WindN),2)) * 0.6; //wind speed in kt
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float windScale = 15.0/(5.0 + windEffect); //wave scale
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float waveRoughness = 0.05 + smoothstep(0.0, 50.0, windEffect); //wave roughness filter
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if (Status == 1){
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cover = min(min(min(min(CloudCover0, CloudCover1),CloudCover2),CloudCover3),CloudCover4);
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} else {
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// hack to allow for Overcast not to be set by Local Weather
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if (Overcast == 0){
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cover = 5;
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} else {
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cover = Overcast * 5;
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}
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}
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//vec4 viewt = normalize(waterTex4);
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vec4 viewt = vec4(-E, 0.0) * 0.6;
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vec4 disdis = texture2D(water_dudvmap, vec2(waterTex2 * tscale)* windScale * 2.0) * 2.0 - 1.0;
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vec4 dist1 = texture2D(water_dudvmap, vec2(waterTex1 + disdis*sca2)* windScale * 2.0) * 2.0 - 1.0;
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vec4 fdist = normalize(dist1);
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fdist = -fdist;
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fdist *= sca;
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//normalmap
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rotationmatrix(-relWinddir, RotationMatrix);
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vec4 nmap0 = texture2D(water_normalmap, vec2((waterTex1 + disdis*sca2) * RotationMatrix ) * windScale * 2.0) * 2.0 - 1.0;
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vec4 nmap2 = texture2D(water_normalmap, vec2(waterTex2 * tscale * RotationMatrix ) * windScale * 2.0) * 2.0 - 1.0;
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vec4 nmap3 = texture2D(bowwave_nmap, gl_TexCoord[0].st) * 2.0 - 1.0;
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vec4 vNorm = normalize(mix(nmap3, nmap0 + nmap2, 0.3 )* waveRoughness);
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vNorm = -vNorm;
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//load reflection
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vec4 tmp = vec4(lightdir, 0.0);
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vec4 refTex = texture2D(water_reflection, vec2(tmp + waterTex1) * 32.0) ;
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vec4 refTexGrey = texture2D(water_reflection_grey, vec2(tmp + waterTex1) * 32.0) ;
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vec4 refl ;
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// cover = 0;
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/*if(cover >= 1.5){
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refl= normalize(refTex);
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}
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else
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{
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refl = normalize(refTexGrey);
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refl.r *= (0.75 + 0.15 * cover);
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refl.g *= (0.80 + 0.15 * cover);
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refl.b *= (0.875 + 0.125 * cover);
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refl.a *= 1.0;
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}
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*/
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refl.r = sea_r;
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refl.g = sea_g;
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refl.b = sea_b;
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refl.a = 1.0;
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float intensity;
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// de-saturate for reduced light
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refl.rgb = mix(refl.rgb, vec3 (0.248, 0.248, 0.248), 1.0 - smoothstep(0.1, 0.8, ground_scattering));
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// de-saturate light for overcast haze
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intensity = length(refl.rgb);
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refl.rgb = mix(refl.rgb, intensity * vec3 (1.0, 1.0, 1.0), 0.5 * smoothstep(0.1, 0.9, overcast));
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vec3 N0 = vec3(texture2D(water_normalmap, vec2((waterTex1 + disdis*sca2)* RotationMatrix) * windScale * 2.0) * 2.0 - 1.0);
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vec3 N1 = vec3(texture2D(water_normalmap, vec2(waterTex2 * tscale * RotationMatrix ) * windScale * 2.0) * 2.0 - 1.0);
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vec3 N2 = vec3(texture2D(bowwave_nmap, gl_TexCoord[0].st)*2.0-1.0);
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//vec3 Nf = normalize((normal+N0+N1)*waveRoughness);
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vec3 N = normalize(mix(normal+N2, normal+N0+N1, 0.3)* waveRoughness);
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N = -N;
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// specular
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specular_light = gl_Color.rgb;
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vec3 specular_color = vec3(specular_light)
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* pow(max(0.0, dot(N, H)), water_shininess) * 6.0;
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vec4 specular = vec4(specular_color, 0.5);
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specular = specular * saturation * 0.3;
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//calculate fresnel
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vec4 invfres = vec4( dot(vNorm, viewt) );
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vec4 fres = vec4(1.0) + invfres;
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refl *= fres;
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vec4 alpha0 = texture2D(alpha_tex, gl_TexCoord[0].st);
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//calculate final colour
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vec4 ambient_light;
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ambient_light.rgb = max(specular_light.rgb, vec3(0.1, 0.1, 0.1));
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ambient_light.a = 1.0;
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vec4 finalColor;
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finalColor = refl + specular * smoothstep(0.3, 0.6, ground_scattering);
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//add foam
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float foamSlope = 0.05 + 0.01 * windScale;
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//float waveSlope = mix(N0.g, N1.g, 0.25);
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vec4 foam_texel = texture2D(sea_foam, vec2(waterTex2 * tscale) * 50.0);
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float waveSlope = N.g;
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if (windEffect >= 12.0)
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if (waveSlope >= foamSlope){
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finalColor = mix(finalColor, max(finalColor, finalColor + foam_texel), smoothstep(foamSlope, 0.5, N.g));
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}
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//generate final colour
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finalColor *= ambient_light;//+ alpha0 * 0.35;
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float delta_z = hazeLayerAltitude - eye_alt;
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if (dist > 40.0)
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{
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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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// 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 ));
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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 ));
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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, eye_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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float 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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{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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// high altitude desaturation of the haze color
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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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hazeColor = intensity * normalize (mix(hazeColor, intensity * vec3 (1.0,1.0,1.0), 0.7* smoothstep(5000.0, 50000.0, eye_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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}
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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.rgb *= eqColorFactor * eShade;
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hazeColor.rgb = max(hazeColor.rgb, minLight.rgb);
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finalColor.rgb = mix(hazeColor, finalColor.rgb,transmission);
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}
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gl_FragColor = vec4(finalColor.rgb, alpha0.a * 1.35);
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}
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