307 lines
9.5 KiB
GLSL
307 lines
9.5 KiB
GLSL
// -*-C++-*-
|
|
#version 120
|
|
|
|
// Shader that uses OpenGL state values to do per-pixel lighting
|
|
//
|
|
// The only light used is gl_LightSource[0], which is assumed to be
|
|
// directional.
|
|
//
|
|
// Diffuse colors come from the gl_Color, ambient from the material. This is
|
|
// equivalent to osg::Material::DIFFUSE.
|
|
// Haze part added by Thorsten Renk, Oct. 2011
|
|
|
|
|
|
#define MODE_OFF 0
|
|
#define MODE_DIFFUSE 1
|
|
#define MODE_AMBIENT_AND_DIFFUSE 2
|
|
|
|
// The constant term of the lighting equation that doesn't depend on
|
|
// the surface normal is passed in gl_{Front,Back}Color. The alpha
|
|
// component is set to 1 for front, 0 for back in order to work around
|
|
// bugs with gl_FrontFacing in the fragment shader.
|
|
varying vec4 diffuse_term;
|
|
varying vec3 normal;
|
|
varying vec3 relPos;
|
|
varying vec2 rawPos;
|
|
varying vec3 worldPos;
|
|
|
|
|
|
varying float mie_angle;
|
|
varying float steepness;
|
|
|
|
|
|
uniform int colorMode;
|
|
uniform float hazeLayerAltitude;
|
|
uniform float terminator;
|
|
uniform float terrain_alt;
|
|
uniform float avisibility;
|
|
uniform float visibility;
|
|
uniform float overcast;
|
|
uniform float ground_scattering;
|
|
uniform float eye_alt;
|
|
uniform float moonlight;
|
|
|
|
uniform bool use_IR_vision;
|
|
|
|
uniform mat4 osg_ViewMatrixInverse;
|
|
|
|
float earthShade;
|
|
float yprime_alt;
|
|
//float mie_angle;
|
|
|
|
|
|
// This is the value used in the skydome scattering shader - use the same here for consistency?
|
|
const float EarthRadius = 5800000.0;
|
|
const float terminator_width = 200000.0;
|
|
|
|
vec3 moonlight_perception (in vec3 light);
|
|
void setupShadows(vec4 eyeSpacePos);
|
|
|
|
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 < -15.0) {return 0.0;}
|
|
|
|
return e / pow((1.0 + a * exp(-b * (x-c)) ),(1.0/d));
|
|
}
|
|
|
|
|
|
void main()
|
|
{
|
|
|
|
vec4 light_diffuse;
|
|
vec4 light_ambient;
|
|
vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
|
|
vec3 moonLightColor = vec3 (0.095, 0.095, 0.15) * moonlight;
|
|
moonLightColor = moonlight_perception (moonLightColor);
|
|
|
|
//float yprime_alt;
|
|
float yprime;
|
|
float lightArg;
|
|
float intensity;
|
|
float vertex_alt;
|
|
float scattering;
|
|
|
|
rawPos = gl_Vertex.xy;
|
|
vec4 eyePos = gl_ModelViewMatrix * gl_Vertex;
|
|
worldPos = (osg_ViewMatrixInverse * eyePos).xyz;
|
|
steepness = dot(normalize(gl_Normal), vec3 (0.0, 0.0, 1.0));
|
|
|
|
|
|
// this code is copied from default.vert
|
|
|
|
//vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex;
|
|
gl_Position = ftransform();
|
|
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
|
|
normal = gl_NormalMatrix * gl_Normal;
|
|
//nvec = (gl_NormalMatrix * gl_Normal).xy;
|
|
vec4 ambient_color, diffuse_color;
|
|
if (colorMode == MODE_DIFFUSE) {
|
|
diffuse_color = gl_Color;
|
|
ambient_color = gl_FrontMaterial.ambient;
|
|
} else if (colorMode == MODE_AMBIENT_AND_DIFFUSE) {
|
|
diffuse_color = gl_Color;
|
|
ambient_color = gl_Color;
|
|
} else {
|
|
diffuse_color = gl_FrontMaterial.diffuse;
|
|
ambient_color = gl_FrontMaterial.ambient;
|
|
}
|
|
|
|
|
|
|
|
// here start computations for the haze layer
|
|
// we need several geometrical quantities
|
|
|
|
|
|
// first current altitude of eye position in model space
|
|
vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);
|
|
|
|
// and relative position to vector
|
|
relPos = gl_Vertex.xyz - ep.xyz;
|
|
|
|
//ecViewdir = (gl_ModelViewMatrix * (ep - gl_Vertex)).xyz;
|
|
|
|
// unfortunately, we need the distance in the vertex shader, although the more accurate version
|
|
// is later computed in the fragment shader again
|
|
float dist = length(relPos);
|
|
|
|
|
|
// altitude of the vertex in question, somehow zero leads to artefacts, so ensure it is at least 100m
|
|
vertex_alt = max(gl_Vertex.z,100.0);
|
|
scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, vertex_alt);
|
|
|
|
|
|
// early culling of vertices which can't be seen due to ground haze despite being in aloft visibility range
|
|
|
|
//float delta_z = hazeLayerAltitude - eye_alt;
|
|
//if (((dist * (relPos.z - delta_z)/relPos.z > visibility ) && (relPos.z < 0.0) && (delta_z < 0.0) && (dist > 30000.0)))
|
|
if (0==1)
|
|
{
|
|
gl_Position = vec4(0.0, 0.0, -1000.0, 1.0); // move outside of view frustrum, gets culled before reaching fragment shader
|
|
earthShade = 1.0;
|
|
mie_angle = 1.0;
|
|
yprime_alt = 0.0;
|
|
}
|
|
else
|
|
{
|
|
|
|
|
|
// branch dependent on daytime
|
|
|
|
if (terminator < 1000000.0) // the full, sunrise and sunset computation
|
|
{
|
|
|
|
|
|
// establish coordinates relative 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
|
|
yprime = -dot(relPos, lightHorizon);
|
|
|
|
// this gets an altitude correction, higher terrain gets to see the sun earlier
|
|
yprime_alt = yprime - sqrt(2.0 * EarthRadius * vertex_alt);
|
|
|
|
// two times terminator width governs how quickly light fades into shadow
|
|
// now the light-dimming factor
|
|
earthShade = 0.6 * (1.0 - smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt)) + 0.4;
|
|
|
|
// parametrized version of the Flightgear ground lighting function
|
|
lightArg = (terminator-yprime_alt)/100000.0;
|
|
|
|
// directional scattering for low sun
|
|
if (lightArg < 10.0)
|
|
{mie_angle = (0.5 * dot(normalize(relPos), normalize(lightFull)) ) + 0.5;}
|
|
else
|
|
{mie_angle = 1.0;}
|
|
|
|
|
|
|
|
|
|
light_diffuse.b = light_func(lightArg, 1.330e-05, 0.264, 3.827, 1.08e-05, 1.0);
|
|
light_diffuse.g = light_func(lightArg, 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 = light_diffuse * scattering;
|
|
|
|
//light_ambient.b = light_func(lightArg, 0.000506, 0.131, -3.315, 0.000457, 0.5);
|
|
//light_ambient.g = light_func(lightArg, 2.264e-05, 0.134, 0.967, 3.66e-05, 0.4);
|
|
light_ambient.r = light_func(lightArg, 0.236, 0.253, 1.073, 0.572, 0.33);
|
|
light_ambient.g = light_ambient.r * 0.4/0.33; //light_func(lightArg, 0.236, 0.253, 1.073, 0.572, 0.4);
|
|
light_ambient.b = light_ambient.r * 0.5/0.33; //light_func(lightArg, 0.236, 0.253, 1.073, 0.572, 0.5);
|
|
light_ambient.a = 1.0;
|
|
|
|
|
|
|
|
|
|
// correct ambient light intensity and hue before sunrise
|
|
if (earthShade < 0.5)
|
|
{
|
|
intensity = length(light_ambient.rgb);
|
|
light_ambient.rgb = intensity * normalize(mix(light_ambient.rgb, shadedFogColor, 1.0 -smoothstep(0.4, 0.8,earthShade) ));
|
|
light_ambient.rgb = light_ambient.rgb + moonLightColor * (1.0 - smoothstep(0.4, 0.5, earthShade));
|
|
|
|
intensity = length(light_diffuse.rgb);
|
|
light_diffuse.rgb = intensity * normalize(mix(light_diffuse.rgb, shadedFogColor, 1.0 -smoothstep(0.4, 0.7,earthShade) ));
|
|
}
|
|
|
|
|
|
// the haze gets the light at the altitude of the haze top if the vertex in view is below
|
|
// but the light at the vertex if the vertex is above
|
|
|
|
vertex_alt = max(vertex_alt,hazeLayerAltitude);
|
|
|
|
if (vertex_alt > hazeLayerAltitude)
|
|
{
|
|
if (dist > 0.8 * avisibility)
|
|
{
|
|
vertex_alt = mix(vertex_alt, hazeLayerAltitude, smoothstep(0.8*avisibility, avisibility, dist));
|
|
yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
vertex_alt = hazeLayerAltitude;
|
|
yprime_alt = yprime -sqrt(2.0 * EarthRadius * vertex_alt);
|
|
}
|
|
|
|
}
|
|
else // the faster, full-day version without lightfields
|
|
{
|
|
//vertex_alt = max(gl_Vertex.z,100.0);
|
|
|
|
earthShade = 1.0;
|
|
mie_angle = 1.0;
|
|
|
|
if (terminator > 3000000.0)
|
|
{light_diffuse = vec4 (1.0, 1.0, 1.0, 1.0);
|
|
light_ambient = vec4 (0.33, 0.4, 0.5, 1.0); }
|
|
else
|
|
{
|
|
|
|
lightArg = (terminator/100000.0 - 10.0)/20.0;
|
|
light_diffuse.b = 0.78 + lightArg * 0.21;
|
|
light_diffuse.g = 0.907 + lightArg * 0.091;
|
|
light_diffuse.r = 0.904 + lightArg * 0.092;
|
|
light_diffuse.a = 1.0;
|
|
|
|
//light_ambient.b = 0.41 + lightArg * 0.08;
|
|
//light_ambient.g = 0.333 + lightArg * 0.06;
|
|
light_ambient.r = 0.316 + lightArg * 0.016;
|
|
light_ambient.g = light_ambient.r * 0.4/0.33;
|
|
light_ambient.b = light_ambient.r * 0.5/0.33;
|
|
light_ambient.a = 1.0;
|
|
}
|
|
|
|
light_diffuse = light_diffuse * scattering;
|
|
yprime_alt = -sqrt(2.0 * EarthRadius * hazeLayerAltitude);
|
|
}
|
|
|
|
|
|
// a sky/earth irradiation map model - the sky creates much more diffuse radiation than the ground, so
|
|
// steep faces end up shaded more
|
|
|
|
light_ambient = light_ambient * ((1.0+steepness)/2.0 * 1.2 + (1.0-steepness)/2.0 * 0.2);
|
|
|
|
|
|
// deeper shadows when there is lots of direct light
|
|
|
|
float shade_depth = 1.0 * smoothstep (0.6,0.95,ground_scattering) * (1.0-smoothstep(0.1,0.5,overcast)) * smoothstep(0.4,1.5,earthShade);
|
|
|
|
light_ambient.rgb = light_ambient.rgb * (1.0 - shade_depth);
|
|
light_diffuse.rgb = light_diffuse.rgb * (1.0 + 1.2 * shade_depth);
|
|
|
|
if (use_IR_vision)
|
|
{
|
|
light_ambient.rgb = max(light_ambient.rgb, vec3 (0.5, 0.5, 0.5));
|
|
}
|
|
|
|
// default lighting based on texture and material using the light we have just computed
|
|
|
|
diffuse_term = diffuse_color* light_diffuse;
|
|
vec4 constant_term = gl_FrontMaterial.emission + ambient_color *
|
|
(gl_LightModel.ambient + light_ambient);
|
|
// Super hack: if diffuse material alpha is less than 1, assume a
|
|
// transparency animation is at work
|
|
// if (gl_FrontMaterial.diffuse.a < 1.0)
|
|
// diffuse_term.a = gl_FrontMaterial.diffuse.a;
|
|
//else
|
|
// diffuse_term.a = gl_Color.a;
|
|
diffuse_term.a = yprime_alt;
|
|
// Another hack for supporting two-sided lighting without using
|
|
// gl_FrontFacing in the fragment shader.
|
|
gl_FrontColor.rgb = constant_term.rgb; //gl_FrontColor.a = 1.0;
|
|
gl_BackColor.rgb = constant_term.rgb; //gl_BackColor.a = 0.0;
|
|
gl_FrontColor.a = mie_angle;
|
|
gl_BackColor.a = mie_angle;
|
|
}
|
|
|
|
setupShadows(eyePos);
|
|
}
|
|
|
|
|