351 lines
9.7 KiB
C++
351 lines
9.7 KiB
C++
// -*-C++-*-
|
|
|
|
// 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 vec4 rawPos;
|
|
|
|
|
|
//varying vec3 hazeColor;
|
|
//varying float fogCoord;
|
|
|
|
uniform sampler2D texture;
|
|
uniform sampler3D NoiseTex;
|
|
uniform sampler2D snow_texture;
|
|
|
|
//varying float ct;
|
|
//varying float delta_z;
|
|
//varying float alt;
|
|
|
|
varying float earthShade;
|
|
//varying float yprime;
|
|
//varying float vertex_alt;
|
|
varying float yprime_alt;
|
|
varying float mie_angle;
|
|
varying float steepness;
|
|
|
|
|
|
uniform float visibility;
|
|
uniform float avisibility;
|
|
uniform float scattering;
|
|
//uniform float ground_scattering;
|
|
uniform float terminator;
|
|
uniform float terrain_alt;
|
|
uniform float hazeLayerAltitude;
|
|
uniform float overcast;
|
|
//uniform float altitude;
|
|
uniform float eye_alt;
|
|
uniform float mysnowlevel;
|
|
uniform float dust_cover_factor;
|
|
uniform float fogstructure;
|
|
|
|
const float EarthRadius = 5800000.0;
|
|
const float terminator_width = 200000.0;
|
|
|
|
float alt;
|
|
|
|
float luminance(vec3 color)
|
|
{
|
|
return dot(vec3(0.212671, 0.715160, 0.072169), color);
|
|
}
|
|
|
|
|
|
float light_func (in float x, in float a, in float b, in float c, in float d, in float e)
|
|
{
|
|
x = x - 0.5;
|
|
|
|
// use the asymptotics to shorten computations
|
|
if (x > 30.0) {return e;}
|
|
if (x < -15.0) {return 0.0;}
|
|
|
|
return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d));
|
|
}
|
|
|
|
// 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
|
|
|
|
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; // 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));
|
|
}
|
|
|
|
}
|
|
|
|
void main()
|
|
{
|
|
|
|
// this is taken from default.frag
|
|
vec3 n;
|
|
float NdotL, NdotHV, fogFactor;
|
|
vec4 color = gl_Color;
|
|
vec3 lightDir = gl_LightSource[0].position.xyz;
|
|
vec3 halfVector = gl_LightSource[0].halfVector.xyz;
|
|
vec4 texel;
|
|
vec4 snow_texel;
|
|
vec4 fragColor;
|
|
vec4 specular = vec4(0.0);
|
|
float intensity;
|
|
|
|
|
|
|
|
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);
|
|
|
|
NdotL = dot(n, lightDir);
|
|
if (NdotL > 0.0) {
|
|
color += diffuse_term * NdotL;
|
|
NdotHV = max(dot(n, halfVector), 0.0);
|
|
if (gl_FrontMaterial.shininess > 0.0)
|
|
specular.rgb = (gl_FrontMaterial.specular.rgb
|
|
* light_specular.rgb
|
|
* pow(NdotHV, gl_FrontMaterial.shininess));
|
|
}
|
|
color.a = diffuse_term.a;
|
|
// 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);
|
|
texel = texture2D(texture, gl_TexCoord[0].st);
|
|
snow_texel = texture2D(snow_texture, gl_TexCoord[0].st);
|
|
|
|
|
|
// this is the snow and dust generating part, ger some noise vectors
|
|
vec4 noisevec = texture3D(NoiseTex, (rawPos.xyz)*0.003); // small scale noise
|
|
//vec4 nvL = texture3D(NoiseTex, (rawPos.xyz)*0.00066);
|
|
vec4 nvL = texture3D(NoiseTex, (rawPos.xyz)*0.0001); // large scale noise
|
|
vec4 nvR = texture3D(NoiseTex, (rawPos.xyz)*0.00003); // really large scale noise
|
|
|
|
//float ns=0.06;
|
|
// ns += nvL[0]*0.4;
|
|
//ns += nvL[1]*0.6;
|
|
//ns += nvL[2]*2.0;
|
|
//ns += nvL[3]*4.0;
|
|
//ns += noisevec[0]*0.1;
|
|
//ns += noisevec[1]*0.4;
|
|
|
|
//ns += noisevec[2]*0.8;
|
|
//ns += noisevec[3]*2.1;
|
|
|
|
// gradient effect for snow
|
|
|
|
|
|
// mix dust
|
|
vec4 dust_color = vec4 (0.76, 0.71, 0.56, 1.0);
|
|
//dust_color.rgb = dust_color.rgb * nvL[1];
|
|
|
|
texel = mix(texel, dust_color, clamp(0.5 * dust_cover_factor + 3.0 * dust_cover_factor * nvL[1],0.0, 1.0) );
|
|
|
|
|
|
float snow_alpha = smoothstep(0.7, 0.8, abs(steepness));
|
|
|
|
//vec4 snow_texel = clamp(ns+nvL[2]*4.1+vec4(0.1, 0.1, nvL[2]*2.2, 1.0), 0.7, 1.0);
|
|
//snow_texel.a = snow_alpha * snow_texel.a;
|
|
|
|
|
|
|
|
// mix snow
|
|
texel = mix(texel, snow_texel, smoothstep(mysnowlevel, mysnowlevel+200.0, snow_alpha * (relPos.z + eye_alt)+ (noisevec[1] * abs(noisevec[1])+ nvL[1])*1500.0));
|
|
|
|
// gradient
|
|
//fragColor = mix(vec4(ns-0.30, ns-0.29, ns-0.37, 1.0), fragColor, smoothstep(0.0, 0.40, steepness));// +nvL[2]*1.3));
|
|
|
|
fragColor = color * texel + specular;
|
|
|
|
// here comes the terrain haze model
|
|
|
|
|
|
float delta_z = hazeLayerAltitude - eye_alt;
|
|
float dist = length(relPos);
|
|
|
|
|
|
if (dist > 40.0)
|
|
{
|
|
|
|
alt = eye_alt;
|
|
|
|
|
|
float transmission;
|
|
float vAltitude;
|
|
float delta_zv;
|
|
float H;
|
|
float distance_in_layer;
|
|
float transmission_arg;
|
|
|
|
// 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;
|
|
|
|
|
|
float eqColorFactor;
|
|
|
|
//float scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, relPos.z + eye_alt);
|
|
|
|
|
|
if (visibility < avisibility)
|
|
{
|
|
transmission_arg = transmission_arg + (distance_in_layer/(1.0 * visibility + 0.8 * visibility * fogstructure * (( 0.4 * nvL[1] + 0.6 * nvR[1]) -0.1) ));
|
|
//transmission_arg = transmission_arg + (distance_in_layer/visibility);
|
|
// this combines the Weber-Fechner intensity
|
|
eqColorFactor = 1.0 - 0.1 * delta_zv/visibility - (1.0 -scattering);
|
|
|
|
}
|
|
else
|
|
{
|
|
transmission_arg = transmission_arg + (distance_in_layer/(1.0 * avisibility + 0.8 * avisibility * fogstructure * (( 0.4 * nvL[1] + 0.6 * nvR[1]) -0.1) ));
|
|
//transmission_arg = transmission_arg + (distance_in_layer/avisibility);
|
|
// this combines the Weber-Fechner intensity
|
|
eqColorFactor = 1.0 - 0.1 * delta_zv/avisibility - (1.0 -scattering);
|
|
}
|
|
|
|
|
|
|
|
transmission = fog_func(transmission_arg);
|
|
|
|
// there's always residual intensity, we should never be driven to zero
|
|
if (eqColorFactor < 0.2) eqColorFactor = 0.2;
|
|
|
|
|
|
float lightArg = (terminator-yprime_alt)/100000.0;
|
|
|
|
vec3 hazeColor;
|
|
|
|
hazeColor.b = light_func(lightArg, 1.330e-05, 0.264, 2.527, 1.08e-05, 1.0);
|
|
hazeColor.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
|
|
hazeColor.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
|
|
|
|
|
|
// now dim the light for haze
|
|
earthShade = 0.9 * smoothstep(terminator_width+ terminator, -terminator_width + terminator, yprime_alt) + 0.1;
|
|
|
|
// Mie-like factor
|
|
|
|
if (lightArg < 5.0)
|
|
{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);
|
|
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* vec3 (0.45, 0.6, 0.8), 1.0 -smoothstep(0.25, fade_out,earthShade) ));
|
|
|
|
// change haze color to blue hue for strong fogging
|
|
//intensity = length(hazeColor);
|
|
hazeColor = intensity * normalize(mix(hazeColor, 2.0 * vec3 (0.55, 0.6, 0.8), (1.0-smoothstep(0.3,0.8,eqColorFactor))));
|
|
|
|
|
|
// reduce haze intensity when looking at shaded surfaces, only in terminator region
|
|
|
|
float shadow = mix( min(1.0 + dot(normal,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));
|
|
|
|
// randomness
|
|
|
|
//hazeColor.rgb = hazeColor.rgb + 0.2 * hazeColor.rgb * nvL[1];
|
|
|
|
// determine the right mix of transmission and haze
|
|
|
|
//fragColor.xyz = transmission * fragColor.xyz + (1.0-transmission) * eqColorFactor * hazeColor * earthShade;
|
|
|
|
|
|
//fragColor.rgb = mix(fragColor.rgb, vec3 (1.0, 1.0, 1.0), overcast );
|
|
|
|
|
|
fragColor.xyz = mix(eqColorFactor * hazeColor * earthShade, fragColor.xyz,transmission);
|
|
|
|
|
|
gl_FragColor = fragColor;
|
|
|
|
|
|
}
|
|
else // if dist < 40.0 no fogging at all
|
|
{
|
|
gl_FragColor = fragColor;
|
|
}
|
|
|
|
|
|
//gl_FragColor.rgb = 5.0 * nvL[1] * vec3 (1.0, 1.0, 1.0);
|
|
|
|
}
|
|
|