1
0
Fork 0
fgdata/Shaders/airfield-ALS.frag
Scott Giese 76f7f1b698 Photoscenery: Initial commit
Author: Nathaniel Warner
2020-11-23 19:48:01 -06:00

536 lines
15 KiB
C++

// -*-C++-*-
#version 120
// written by Thorsten Renk, Oct 2011, based on default.frag
// Ambient term comes in gl_Color.rgb.
varying vec4 diffuse_term;
varying vec3 normal;
varying vec3 relPos;
varying vec3 worldPos;
varying vec2 rawPos;
varying vec3 ecViewdir;
varying vec2 orthoTexCoord;
uniform sampler2D texture;
uniform sampler2D overlay_texture;
uniform sampler2D grain_texture;
uniform sampler2D orthophotoTexture;
varying float steepness;
uniform float visibility;
uniform float avisibility;
uniform float scattering;
uniform float terminator;
uniform float terrain_alt;
uniform float hazeLayerAltitude;
uniform float overcast;
uniform float eye_alt;
uniform float snowlevel;
uniform float dust_cover_factor;
uniform float fogstructure;
uniform float cloud_self_shading;
uniform float snow_thickness_factor;
uniform float grit_alpha;
uniform float overlay_bias;
uniform float overlay_alpha;
uniform float base_layer_magnification;
uniform float overlay_layer_magnification;
uniform float grain_layer_magnification;
uniform float wetness;
uniform float air_pollution;
uniform float season;
uniform float landing_light1_offset;
uniform float landing_light2_offset;
uniform float landing_light3_offset;
uniform int quality_level;
uniform int tquality_level;
uniform int cloud_shadow_flag;
uniform int use_overlay;
uniform int use_grain;
uniform int use_color_overlay;
uniform int use_searchlight;
uniform int use_landing_light;
uniform int use_alt_landing_light;
uniform bool orthophotoAvailable;
const float EarthRadius = 5800000.0;
const float terminator_width = 200000.0;
float alt;
float eShade;
float yprime_alt;
float mie_angle;
float shadow_func (in float x, in float y, in float noise, in float dist);
float Noise2D(in vec2 coord, in float wavelength);
float Noise3D(in vec3 coord, in float wavelength);
float fog_func (in float targ, in float alt);
float rayleigh_in_func(in float dist, in float air_pollution, in float avisibility, in float eye_alt, in float vertex_alt);
float alt_factor(in float eye_alt, in float vertex_alt);
float light_distance_fading(in float dist);
float fog_backscatter(in float avisibility);
vec3 rayleigh_out_shift(in vec3 color, in float outscatter);
vec3 get_hazeColor(in float light_arg);
vec3 searchlight();
vec3 landing_light(in float offset, in float offsetv);
vec3 filter_combined (in vec3 color) ;
float getShadowing();
float detail_fade (in float scale, in float angle, in float dist)
{
float fade_dist = 4000.0 * scale * angle;
return 1.0 - smoothstep(0.5 * fade_dist, fade_dist, dist);
}
// this determines how light is attenuated in the distance
// physically this should be exp(-arg) but for technical reasons we use a sharper cutoff
// for distance > visibility
void main()
{
//if ((gl_FragCoord.y < ylimit) && (gl_FragCoord.x > zlimit1) && (gl_FragCoord.x < zlimit2))
// {discard;}
float effective_scattering = min(scattering, cloud_self_shading);
yprime_alt = diffuse_term.a;
//diffuse_term.a = 1.0;
mie_angle = gl_Color.a;
vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
float dist = length(relPos);
float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
// this is taken from default.frag
vec3 n;
float NdotL, NdotHV, fogFactor;
vec4 color = gl_Color;
color.a = 1.0;
vec3 lightDir = gl_LightSource[0].position.xyz;
vec3 halfVector;
if (quality_level<6)
{halfVector = gl_LightSource[0].halfVector.xyz;}
else
{halfVector = normalize(normalize(lightDir) + normalize(ecViewdir));}
vec4 texel;
vec4 overlay_texel;
vec4 grain_texel;
vec4 snow_texel;
vec4 fragColor;
vec4 specular = vec4(0.0);
float intensity;
// get noise at different wavelengths
// used: 5m, 5m gradient, 10m, 10m gradient: heightmap of the closeup terrain, 10m also snow
// 500m: distortion and overlay
// 1500m: overlay, detail, dust, fog
// 2000m: overlay, detail, snow, fog
float noise_01m;
float noise_1m = Noise2D(rawPos.xy, 1.0);
float noise_2m;
float noise_10m = Noise2D(rawPos.xy, 10.0);
float noise_5m = Noise2D(rawPos.xy,5.0);
float noise_50m = Noise2D(rawPos.xy, 50.0);
float noise_1500m = Noise3D(worldPos.xyz, 1500.0);
float noise_2000m = Noise3D(worldPos.xyz, 2000.0);
//
// get the texels
texel = texture2D(texture, gl_TexCoord[0].st * base_layer_magnification);
float local_autumn_factor = texel.a;
if (orthophotoAvailable) {
vec4 sat_texel = texture2D(orthophotoTexture, orthoTexCoord);
if (sat_texel.a > 0) {
texel.rgb = sat_texel.rgb;
}
}
float distortion_factor = 1.0;
float noise_term;
float snow_alpha;
if (quality_level > 3)
{
//snow_texel = texture2D(snow_texture, gl_TexCoord[0].st);
snow_texel = vec4 (0.95, 0.95, 0.95, 1.0) * (0.9 + 0.1* noise_50m + 0.1* (1.0 - noise_10m) );
snow_texel.a = 1.0;
noise_term = 0.1 * (noise_50m-0.5);
noise_term = noise_term + 0.2 * (noise_10m -0.5) * (1.0 - smoothstep(10000.0, 16000.0, dist) ) ;
noise_term = noise_term + 0.3 * (noise_5m -0.5) * (1.0 - smoothstep(1200.0 , 2000.0 , dist) ) ;
if (dist < 1000.0){ noise_term = noise_term + 0.3 * (noise_1m -0.5) * (1.0 - smoothstep(500.0 , 1000.0 , dist) );}
snow_texel.a = snow_texel.a * 0.2+0.8* smoothstep(0.2,0.8, 0.3 +noise_term + snow_thickness_factor +0.0001*(relPos.z +eye_alt -snowlevel) );
}
if (use_overlay == 1)
{
overlay_texel = texture2D(overlay_texture, gl_TexCoord[0].st * overlay_layer_magnification);
texel.rgb = mix(texel.rgb, overlay_texel.rgb, overlay_texel.a * overlay_alpha * smoothstep(0.45, 0.65, overlay_bias + (0.5 * noise_1m + 0.1 * noise_2m + 0.4 * noise_10m)));
}
if (use_grain == 1)
{
grain_texel = texture2D(grain_texture, gl_TexCoord[0].st * grain_layer_magnification);
texel.rgb = mix(texel.rgb, grain_texel.rgb, grain_texel.a);
}
float dist_fact;
float nSum;
float mix_factor;
float water_factor = 0.0;
float water_threshold1;
float water_threshold2;
// get distribution of water when terrain is wet
if ((dist < 3000.0)&& (quality_level > 3) && (wetness>0.0))
{
water_threshold1 = 1.0-0.5* wetness;
water_threshold2 = 1.0 - 0.3 * wetness;
water_factor = smoothstep(water_threshold1, water_threshold2 , 0.5 * (noise_5m + (1.0 -noise_1m))) * (1.0 - smoothstep(1000.0, 3000.0, dist));
}
// color and shade variation of the grass
if (use_color_overlay == 1)
{
float nfact_1m = 3.0 * (noise_1m - 0.5) * detail_fade(1.0, abs(ct),dist);//* (1.0 - smoothstep(3000.0, 6000.0, dist/ abs(ct)));
float nfact_5m = 2.0 * (noise_5m - 0.5) * detail_fade(2.0, abs(ct),dist);;
float nfact_10m = 1.0 * (noise_10m - 0.5);
texel.rgb = texel.rgb * (0.85 + 0.1 * (nfact_1m * detail_fade(1.0, abs(ct),dist) + nfact_5m + nfact_10m) * grit_alpha);
texel.r = texel.r * (1.0 + 0.14 * smoothstep(0.5,0.7, 0.33*(2.0 * noise_10m + (1.0-noise_5m))));
}
// autumn colors
float autumn_factor = season * 2.0 * (1.0 - local_autumn_factor) ;
texel.r = min(1.0, (1.0 + 2.5 * autumn_factor) * texel.r);
texel.g = texel.g;
texel.b = max(0.0, (1.0 - 4.0 * autumn_factor) * texel.b);
if (local_autumn_factor < 1.0)
{
intensity = length(texel.rgb) * (1.0 - 0.5 * smoothstep(1.1,2.0,season));
texel.rgb = intensity * normalize(mix(texel.rgb, vec3(0.23,0.17,0.08), smoothstep(1.1,2.0, season)));
}
vec4 dust_color;
if (quality_level > 3)
{
// mix dust
dust_color = vec4 (0.76, 0.71, 0.56, 1.0);
texel = mix(texel, dust_color, clamp(0.5 * dust_cover_factor + 3.0 * dust_cover_factor * (((noise_1500m - 0.5) * 0.125)+0.125 ),0.0, 1.0) );
// mix snow
snow_alpha = smoothstep(0.75, 0.85, abs(steepness));
texel = mix(texel, snow_texel, snow_texel.a * smoothstep(snowlevel, snowlevel+200.0, snow_alpha * (relPos.z + eye_alt)+ (noise_2000m + 0.1 * noise_10m -0.55) *400.0));
}
// darken grass when wet
texel.rgb = texel.rgb * (1.0 - 0.6 * wetness);
// light computations
vec4 light_specular = gl_LightSource[0].specular ;
// If gl_Color.a == 0, this is a back-facing polygon and the
// normal should be reversed.
//n = (2.0 * gl_Color.a - 1.0) * normal;
//n = normalize(n);
n = normal;//vec3 (nvec.x, nvec.y, sqrt(1.0 -pow(nvec.x,2.0) - pow(nvec.y,2.0) ));
n = normalize(n);
NdotL = dot(n, lightDir);
if ((dist < 200.0) && (quality_level > 4))
{
noise_01m = Noise2D(rawPos.xy,0.1);
NdotL = NdotL + 0.8 * (noise_01m-0.5) * grit_alpha * detail_fade(0.1, abs(ct),dist) * (1.0 - water_factor);
}
if (NdotL > 0.0) {
float shadowmap = getShadowing();
if (cloud_shadow_flag == 1)
{NdotL = NdotL * shadow_func(relPos.x, relPos.y, noise_1500m, dist);}
color += diffuse_term * NdotL * shadowmap;
NdotHV = max(dot(n, halfVector), 0.0);
if (gl_FrontMaterial.shininess > 0.0)
specular.rgb = ((gl_FrontMaterial.specular.rgb + (water_factor * vec3 (1.0, 1.0, 1.0)))
* light_specular.rgb
* pow(NdotHV, (gl_FrontMaterial.shininess + 20.0 * water_factor))
* shadowmap);
}
color.a = 1.0;
// This shouldn't be necessary, but our lighting becomes very
// saturated. Clamping the color before modulating by the texture
// is closer to what the OpenGL fixed function pipeline does.
color = clamp(color, 0.0, 1.0);
vec3 secondary_light = vec3 (0.0,0.0,0.0);
if (use_searchlight == 1)
{
secondary_light += searchlight();
}
if (use_landing_light == 1)
{
secondary_light += landing_light(landing_light1_offset, landing_light3_offset);
}
if (use_alt_landing_light == 1)
{
secondary_light += landing_light(landing_light2_offset, landing_light3_offset);
}
color.rgb +=secondary_light * light_distance_fading(dist);
fragColor = color * texel + specular;
float lightArg = (terminator-yprime_alt)/100000.0;
vec3 hazeColor = get_hazeColor(lightArg);
// Rayleigh color shift due to out-scattering
if ((quality_level > 5) && (tquality_level > 5))
{
float rayleigh_length = 0.5 * avisibility * (2.5 - 1.9 * air_pollution)/alt_factor(eye_alt, eye_alt+relPos.z);
float outscatter = 1.0-exp(-dist/rayleigh_length);
fragColor.rgb = rayleigh_out_shift(fragColor.rgb,outscatter);
// Rayleigh color shift due to in-scattering
float rShade = 1.0 - 0.9 * smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt + 420000.0);
float lightIntensity = length(hazeColor * effective_scattering) * rShade;
vec3 rayleighColor = vec3 (0.17, 0.52, 0.87) * lightIntensity;
float rayleighStrength = rayleigh_in_func(dist, air_pollution, avisibility/max(lightIntensity,0.05), eye_alt, eye_alt + relPos.z);
fragColor.rgb = mix(fragColor.rgb, rayleighColor,rayleighStrength);
}
// here comes the terrain haze model
float delta_z = hazeLayerAltitude - eye_alt;
float mvisibility = min(visibility,avisibility);
if (dist > 0.04 * mvisibility)
{
alt = eye_alt;
float transmission;
float vAltitude;
float delta_zv;
float H;
float distance_in_layer;
float transmission_arg;
// we solve the geometry what part of the light path is attenuated normally and what is through the haze layer
if (delta_z > 0.0) // we're inside the layer
{
if (ct < 0.0) // we look down
{
distance_in_layer = dist;
vAltitude = min(distance_in_layer,mvisibility) * ct;
delta_zv = delta_z - vAltitude;
}
else // we may look through upper layer edge
{
H = dist * ct;
if (H > delta_z) {distance_in_layer = dist/H * delta_z;}
else {distance_in_layer = dist;}
vAltitude = min(distance_in_layer,visibility) * ct;
delta_zv = delta_z - vAltitude;
}
}
else // we see the layer from above, delta_z < 0.0
{
H = dist * -ct;
if (H < (-delta_z)) // we don't see into the layer at all, aloft visibility is the only fading
{
distance_in_layer = 0.0;
delta_zv = 0.0;
}
else
{
vAltitude = H + delta_z;
distance_in_layer = vAltitude/H * dist;
vAltitude = min(distance_in_layer,visibility) * (-ct);
delta_zv = vAltitude;
}
}
// ground haze cannot be thinner than aloft visibility in the model,
// so we need to use aloft visibility otherwise
transmission_arg = (dist-distance_in_layer)/avisibility;
float eqColorFactor;
if (visibility < avisibility)
{
if (quality_level > 3)
{
transmission_arg = transmission_arg + (distance_in_layer/(1.0 * visibility + 1.0 * visibility * fogstructure * 0.06 * (noise_1500m + noise_2000m -1.0) ));
}
else
{
transmission_arg = transmission_arg + (distance_in_layer/visibility);
}
// this combines the Weber-Fechner intensity
eqColorFactor = 1.0 - 0.1 * delta_zv/visibility - (1.0 - effective_scattering);
}
else
{
if (quality_level > 3)
{
transmission_arg = transmission_arg + (distance_in_layer/(1.0 * avisibility + 1.0 * avisibility * fogstructure * 0.06 * (noise_1500m + noise_2000m - 1.0) ));
}
else
{
transmission_arg = transmission_arg + (distance_in_layer/avisibility);
}
// this combines the Weber-Fechner intensity
eqColorFactor = 1.0 - 0.1 * delta_zv/avisibility - (1.0 - effective_scattering);
}
transmission = fog_func(transmission_arg, alt);
// there's always residual intensity, we should never be driven to zero
if (eqColorFactor < 0.2) eqColorFactor = 0.2;
// now dim the light for haze
eShade = 1.0 - 0.9 * smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt);
// Mie-like factor
if (lightArg < 10.0)
{intensity = length(hazeColor);
float mie_magnitude = 0.5 * smoothstep(350000.0, 150000.0, terminator-sqrt(2.0 * EarthRadius * terrain_alt));
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)) );
}
// high altitude desaturation of the haze color
intensity = length(hazeColor);
if (intensity>0.0)
{
hazeColor = intensity * normalize (mix(hazeColor, intensity * vec3 (1.0,1.0,1.0), 0.7* smoothstep(5000.0, 50000.0, alt)));
// blue hue of haze
hazeColor.x = hazeColor.x * 0.83;
hazeColor.y = hazeColor.y * 0.9;
// additional blue in indirect light
float fade_out = max(0.65 - 0.3 *overcast, 0.45);
intensity = length(hazeColor);
hazeColor = intensity * normalize(mix(hazeColor, 1.5* shadedFogColor, 1.0 -smoothstep(0.25, fade_out,eShade) ));
// change haze color to blue hue for strong fogging
hazeColor = intensity * normalize(mix(hazeColor, shadedFogColor, (1.0-smoothstep(0.5,0.9,eqColorFactor))));
// reduce haze intensity when looking at shaded surfaces, only in terminator region
float shadow = mix( min(1.0 + dot(n,lightDir),1.0), 1.0, 1.0-smoothstep(0.1, 0.4, transmission));
hazeColor = mix(shadow * hazeColor, hazeColor, 0.3 + 0.7* smoothstep(250000.0, 400000.0, terminator));
}
//hazeColor = clamp(hazeColor,0.0,1.0);
// don't let the light fade out too rapidly
lightArg = (terminator + 200000.0)/100000.0;
float minLightIntensity = min(0.2,0.16 * lightArg + 0.5);
vec3 minLight = minLightIntensity * vec3 (0.2, 0.3, 0.4);
hazeColor.rgb *= eqColorFactor * eShade;
hazeColor.rgb = max(hazeColor.rgb, minLight.rgb);
fragColor.rgb = mix(hazeColor+secondary_light * fog_backscatter(mvisibility), fragColor.rgb,transmission);
}
fragColor.rgb = filter_combined(fragColor.rgb);
gl_FragColor = fragColor;
}