238 lines
8.7 KiB
GLSL
238 lines
8.7 KiB
GLSL
// -*-C++-*-
|
|
#version 120
|
|
|
|
varying float fogFactor;
|
|
varying vec3 hazeColor;
|
|
|
|
uniform float range; // From /sim/rendering/clouds3d-vis-range
|
|
uniform float detail_range; // From /sim/rendering/clouds3d_detail-range
|
|
uniform float scattering;
|
|
uniform float terminator;
|
|
uniform float altitude;
|
|
uniform float cloud_self_shading;
|
|
uniform float visibility;
|
|
uniform float moonlight;
|
|
uniform float air_pollution;
|
|
uniform float flash;
|
|
uniform float lightning_pos_x;
|
|
uniform float lightning_pos_y;
|
|
uniform float lightning_range;
|
|
|
|
attribute vec3 usrAttr1;
|
|
attribute vec3 usrAttr2;
|
|
|
|
float alpha_factor = usrAttr1.r;
|
|
float shade_factor = usrAttr1.g;
|
|
float cloud_height = usrAttr1.b;
|
|
float bottom_factor = usrAttr2.r;
|
|
float middle_factor = usrAttr2.g;
|
|
float top_factor = usrAttr2.b;
|
|
|
|
const float EarthRadius = 5800000.0;
|
|
|
|
// light_func is a generalized logistic function fit to the light intensity as a function
|
|
// of scaled terminator position obtained from Flightgear core
|
|
|
|
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 0.03;}
|
|
|
|
|
|
return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d));
|
|
}
|
|
|
|
|
|
float mie_func (in float x, in float Mie)
|
|
{
|
|
return x + 2.0 * x * Mie * (1.0 -0.8*x) * (1.0 -0.8*x);
|
|
}
|
|
|
|
void main(void)
|
|
{
|
|
|
|
|
|
//shade_factor = shade_factor * cloud_self_shading;
|
|
//top_factor = top_factor * cloud_self_shading;
|
|
//shade_factor = min(shade_factor, top_factor);
|
|
//middle_factor = min(middle_factor, top_factor);
|
|
//bottom_factor = min(bottom_factor, top_factor);
|
|
|
|
float intensity;
|
|
float mix_factor;
|
|
|
|
|
|
vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
|
|
vec3 moonLightColor = vec3 (0.095, 0.095, 0.15) * moonlight * scattering;
|
|
gl_TexCoord[0] = gl_MultiTexCoord0;
|
|
vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);
|
|
vec4 l = gl_ModelViewMatrixInverse * vec4(0.0,0.0,1.0,1.0);
|
|
vec3 u = normalize(ep.xyz - l.xyz);
|
|
|
|
// Find a rotation matrix that rotates 1,0,0 into u. u, r and w are
|
|
// the columns of that matrix.
|
|
vec3 absu = abs(u);
|
|
vec3 r = normalize(vec3(-u.y, u.x, 0.0));
|
|
vec3 w = cross(u, r);
|
|
|
|
// Do the matrix multiplication by [ u r w pos]. Assume no
|
|
// scaling in the homogeneous component of pos.
|
|
gl_Position = vec4(0.0, 0.0, 0.0, 1.0);
|
|
gl_Position.xyz = gl_Vertex.x * u;
|
|
gl_Position.xyz += gl_Vertex.y * r;
|
|
gl_Position.xyz += gl_Vertex.z * w;
|
|
// Apply Z scaling to allow sprites to be squashed in the z-axis
|
|
gl_Position.z = gl_Position.z * gl_Color.w;
|
|
|
|
// Now shift the sprite to the correct position in the cloud.
|
|
gl_Position.xyz += gl_Color.xyz;
|
|
|
|
// Determine a lighting normal based on the vertex position from the
|
|
// center of the cloud, so that sprite on the opposite side of the cloud to the sun are darker.
|
|
float n = dot(normalize(-gl_LightSource[0].position.xyz),
|
|
normalize(vec3(gl_ModelViewMatrix * vec4(- gl_Position.x, - gl_Position.y, - gl_Position.z, 0.0))));
|
|
|
|
// Determine the position - used for fog and shading calculations
|
|
float fogCoord = length(vec3(gl_ModelViewMatrix * vec4(gl_Color.x, gl_Color.y, gl_Color.z, 1.0)));
|
|
float center_dist = length(vec3(gl_ModelViewMatrix * vec4(0.0,0.0,0.0,1.0)));
|
|
|
|
if ((fogCoord > detail_range) && (fogCoord > center_dist) && (shade_factor < 0.7)) {
|
|
// More than detail_range away, so discard all sprites on opposite side of
|
|
// cloud center by shifting them beyond the view fustrum
|
|
gl_Position = vec4(0.0,0.0,10.0,1.0);
|
|
gl_FrontColor.a = 0.0;
|
|
} else {
|
|
|
|
// Determine the shading of the vertex. We shade it based on it's position
|
|
// in the cloud relative to the sun, and it's vertical position in the cloud.
|
|
float shade = mix(shade_factor, top_factor, smoothstep(-0.3, 0.3, n));
|
|
//if (n < 0) {
|
|
// shade = mix(top_factor, shade_factor, abs(n));
|
|
//}
|
|
|
|
if (gl_Position.z < 0.5 * cloud_height) {
|
|
shade = min(shade, mix(bottom_factor, middle_factor, gl_Position.z * 2.0 / cloud_height));
|
|
} else {
|
|
shade = min(shade, mix(middle_factor, top_factor, gl_Position.z * 2.0 / cloud_height - 1.0));
|
|
}
|
|
|
|
//float h = gl_Position.z / cloud_height;
|
|
//if (h < 0.5) {
|
|
// shade = min(shade, mix(bottom_factor, middle_factor, smoothstep(0.0, 0.5, h)));
|
|
//} else {
|
|
// shade = min(shade, mix(middle_factor, top_factor, smoothstep(2.0 * (h - 0.5)));
|
|
// }
|
|
|
|
// Final position of the sprite
|
|
vec3 relVector = gl_Position.xyz - ep.xyz;
|
|
gl_Position = gl_ModelViewProjectionMatrix * gl_Position;
|
|
|
|
|
|
// Light at the final position
|
|
|
|
// first obtain normal to sun position
|
|
|
|
vec3 lightFull = (gl_ModelViewMatrixInverse * gl_LightSource[0].position).xyz;
|
|
vec3 lightHorizon = normalize(vec3(lightFull.x,lightFull.y, 0.0));
|
|
|
|
|
|
|
|
// yprime is the distance of the vertex into sun direction, corrected for altitude
|
|
// the altitude correction is clamped to reasonable values, sometimes altitude isn't parsed correctly, leading
|
|
// to overbright or overdark clouds
|
|
// float vertex_alt = clamp(altitude * 0.30480 + relVector.z,1000.0,10000.0);
|
|
float vertex_alt = clamp(altitude + relVector.z, 300.0, 10000.0);
|
|
float yprime = -dot(relVector, lightHorizon);
|
|
float yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
|
|
|
|
// two times terminator width governs how quickly light fades into shadow
|
|
float terminator_width = 200000.0;
|
|
float earthShade = 1.0- 0.9* smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt);
|
|
float earthShadeFactor = 1.0 - smoothstep(0.4, 0.5, earthShade);
|
|
|
|
// compute the light at the position
|
|
vec4 light_diffuse;
|
|
|
|
float lightArg = (terminator-yprime_alt)/100000.0;
|
|
|
|
light_diffuse.b = light_func(lightArg -1.2 * air_pollution, 1.330e-05, 0.264, 2.227, 1.08e-05, 1.0);
|
|
light_diffuse.g = light_func(lightArg -0.6 * air_pollution, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
|
|
light_diffuse.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
|
|
light_diffuse.a = 1.0;
|
|
|
|
//light_diffuse *= cloud_self_shading;
|
|
intensity = (1.0 - (0.8 * (1.0 - earthShade))) * length(light_diffuse.rgb);
|
|
light_diffuse.rgb = intensity * normalize(mix(light_diffuse.rgb, shadedFogColor, (1.0 - smoothstep(0.5,0.9, min(scattering, cloud_self_shading) ))));
|
|
|
|
// correct ambient light intensity and hue before sunrise
|
|
if (earthShade < 0.6)
|
|
{
|
|
light_diffuse.rgb = intensity * normalize(mix(light_diffuse.rgb, shadedFogColor, 1.0 -smoothstep(0.1, 0.6,earthShade ) ));
|
|
|
|
}
|
|
|
|
|
|
|
|
gl_FrontColor.rgb = intensity * shade * normalize(mix(light_diffuse.rgb, shadedFogColor, smoothstep(0.1,0.4, (1.0 - shade) ))) ;
|
|
|
|
// lightning
|
|
vec2 lightningRelVector = relVector.xy - vec2(lightning_pos_x, lightning_pos_y);
|
|
float rCoord = length(lightningRelVector);
|
|
|
|
|
|
float rn = 0.5 + 0.5 * fract(gl_Color.x);
|
|
gl_FrontColor.rgb += flash * vec3 (0.43, 0.57, 1.0) * (1.0 - smoothstep(lightning_range, 5.0 * lightning_range, rCoord)) * rn;
|
|
|
|
|
|
// fading of cloudlets
|
|
|
|
if ((fogCoord > (0.9 * detail_range)) && (fogCoord > center_dist) && (shade_factor < 0.7)) {
|
|
// cloudlet is almost at the detail range, so fade it out.
|
|
gl_FrontColor.a = 1.0 - smoothstep(0.9 * detail_range, detail_range, fogCoord);
|
|
} else {
|
|
// As we get within 100m of the sprite, it is faded out. Equally at large distances it also fades out.
|
|
gl_FrontColor.a = min(smoothstep(10.0, 100.0, fogCoord), 1.0 - smoothstep(0.9 * range, range, fogCoord));
|
|
}
|
|
gl_FrontColor.a = gl_FrontColor.a * (1.0 - smoothstep(visibility, 3.0* visibility, fogCoord));
|
|
|
|
fogFactor = exp(-fogCoord/visibility);
|
|
|
|
// haze of ground haze shader is slightly bluish
|
|
hazeColor = light_diffuse.rgb;
|
|
hazeColor.r = hazeColor.r * 0.83;
|
|
hazeColor.g = hazeColor.g * 0.9;
|
|
hazeColor = hazeColor * scattering;
|
|
|
|
|
|
// Mie correction
|
|
float Mie;
|
|
float MieFactor;
|
|
|
|
if (bottom_factor > 0.6)
|
|
{
|
|
MieFactor = dot(normalize(lightFull), normalize(relVector));
|
|
Mie = 1.5 * smoothstep(0.9,1.0, MieFactor) * smoothstep(0.6, 0.8, bottom_factor) * (1.0-earthShadeFactor) ;
|
|
}
|
|
else {Mie = 0.0;}
|
|
|
|
if (Mie > 0.0)
|
|
{
|
|
hazeColor.r = mie_func(hazeColor.r, Mie);
|
|
hazeColor.g = mie_func(hazeColor.g, 0.8* Mie);
|
|
hazeColor.b = mie_func(hazeColor.b, 0.5* Mie);
|
|
|
|
gl_FrontColor.r = mie_func(gl_FrontColor.r, Mie);
|
|
gl_FrontColor.g = mie_func(gl_FrontColor.g, 0.8* Mie);
|
|
gl_FrontColor.b = mie_func(gl_FrontColor.b, 0.5*Mie);
|
|
}
|
|
|
|
gl_FrontColor.rgb = gl_FrontColor.rgb + moonLightColor * earthShadeFactor;
|
|
hazeColor.rgb = hazeColor.rgb + moonLightColor * earthShadeFactor;
|
|
gl_FrontColor.a = gl_FrontColor.a * alpha_factor;
|
|
gl_BackColor = gl_FrontColor;
|
|
}
|
|
}
|