easy-osm2city-podman/full/fgdata/Shaders/surface-light-ALS.frag

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// -*-C++-*-
#version 120
uniform sampler2D texture;
uniform float visibility;
uniform float avisibility;
uniform float hazeLayerAltitude;
uniform float eye_alt;
uniform float terminator;
uniform float size;
uniform bool use_IR_vision;
uniform bool use_night_vision;
varying vec3 relPos;
varying vec2 rawPos;
varying float pixelSize;
float alt;
float Noise2D(in vec2 coord, in float wavelength);
float fog_func (in float targ)
{
float fade_mix;
// for large altitude > 30 km, we switch to some component of quadratic distance fading to
// create the illusion of improved visibility range
targ = 1.25 * targ * smoothstep(0.04,0.06,targ); // need to sync with the distance to which terrain is drawn
if (alt < 30000.0)
{return exp(-targ - targ * targ * targ * targ);}
else if (alt < 50000.0)
{
fade_mix = (alt - 30000.0)/20000.0;
return fade_mix * exp(-targ*targ - pow(targ,4.0)) + (1.0 - fade_mix) * exp(-targ - pow(targ,4.0));
}
else
{
return exp(- targ * targ - pow(targ,4.0));
}
}
float light_sprite (in vec2 coord, in float transmission, in float noise)
{
coord.s = coord.s - 0.5;
coord.t = coord.t - 0.5;
float r = length(coord);
if (pixelSize<1.3) {return 0.08;}
float angle = noise * 6.2832;
float sinphi = dot(vec2 (sin(angle),cos(angle)), normalize(coord));
float sinterm = sin(mod((sinphi-3.0) * (sinphi-3.0),6.2832));
float ray = 0.0;
if (sinterm == 0.0)
{ray = 0.0;}
else
//{ray = clamp(pow(sinterm,10.0),0.0,1.0);}
{ray = sinterm * sinterm * sinterm * sinterm * sinterm * sinterm * sinterm * sinterm * sinterm * sinterm;}
float fogEffect = (1.0-smoothstep(0.4,0.8,transmission));
float halo = 0.2 * exp(-10.0 * r * r);
float base = exp(-80.0*r*r);
ray *= exp(-40.0 * r * r);
float intensity = clamp(ray + base + halo,0.0,1.0) + 0.1 * fogEffect * (1.0-smoothstep(0.3, 0.6,r));
return intensity;
}
void main()
{
float dist = length(relPos);
float delta_z = hazeLayerAltitude - eye_alt;
float transmission;
float vAltitude;
float delta_zv;
float H;
float distance_in_layer;
float transmission_arg;
if (use_IR_vision) {discard;}
// Discard the second and third vertex, which are used for directional lighting
if (gl_Color.a == 0.0) {discard;}
float noise = Noise2D(rawPos.xy ,1.0);
// angle with horizon
float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
// 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,min(visibility, avisibility)) * 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;
if (visibility < avisibility)
{
transmission_arg = transmission_arg + (distance_in_layer/visibility);
}
else
{
transmission_arg = transmission_arg + (distance_in_layer/avisibility);
}
transmission = fog_func(transmission_arg);
float lightArg = terminator/100000.0;
float attenuationScale = 1.0 + 20.0 * (1.0 -smoothstep(-15.0, 0.0, lightArg));
float dist_att = exp(-dist/200.0/size/attenuationScale);
float intensity = light_sprite(gl_TexCoord[0].st,transmission, noise);
vec3 light_color = gl_Color.rgb;
if (use_night_vision)
{light_color.rgb = vec3 (0.0, 1.0, 0.0);}
light_color = mix(light_color, vec3 (1.0, 1.0, 1.0), 0.5 * intensity * intensity);
gl_FragColor = vec4 (clamp(light_color.rgb,0.0,1.0), intensity * transmission * dist_att);
}