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fgdata/Shaders/ws30-ALS-detailed.vert
Stuart Buchanan 71bdd9e99b WS30 - Improved coastline shader
Make the coastline shader consistent between
the coastline texture and the underlying landclass
texture, irrespective of materials.
2023-02-27 22:02:34 +00:00

372 lines
12 KiB
GLSL

// WS30 VERTEX SHADER
// -*-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.
//
// Colors are not assigned in this shader, as they will come from
// the landclass lookup in the fragment shader.
// Haze part added by Thorsten Renk, Oct. 2011
#define MODE_OFF 0
#define MODE_DIFFUSE 1
#define MODE_AMBIENT_AND_DIFFUSE 2
attribute vec2 orthophotoTexCoord;
// 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 light_diffuse_comp;
varying vec3 normal;
varying vec3 relPos;
varying vec2 ground_tex_coord;
varying vec2 rawPos;
varying vec3 worldPos;
//varying vec2 orthoTexCoord;
varying vec4 eyePos;
varying vec4 ecPosition;
// Sent packed into alpha channels
//varying float yprime_alt;
varying float mie_angle;
varying float steepness;
// For water calculations
varying float earthShade;
varying vec3 lightdir;
varying vec4 waterTex1;
varying vec4 waterTex2;
varying vec4 waterTex4;
varying vec3 specular_light;
uniform float osg_SimulationTime;
uniform float WindN;
uniform float WindE;
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;
// From VPBTechnique.cxx
uniform mat4 fg_zUpTransform;
uniform vec3 fg_modelOffset;
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 createRotationMatrix(in float angle, out mat4 rotmat)
{
rotmat = mat4( cos( angle ), -sin( angle ), 0.0, 0.0,
sin( angle ), cos( angle ), 0.0, 0.0,
0.0 , 0.0 , 1.0, 0.0,
0.0 , 0.0 , 0.0, 1.0 );
}
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 = (fg_zUpTransform * gl_Vertex).xy;
worldPos = fg_modelOffset + gl_Vertex.xyz;
eyePos = gl_ModelViewMatrix * gl_Vertex;
steepness = abs(dot(normalize(vec3(fg_zUpTransform * vec4(gl_Normal,1.0))), vec3 (0.0, 0.0, 1.0)));
// this code is copied from default.vert
//vec4 ecPosition = gl_ModelViewMatrix * gl_Vertex;
ecPosition = gl_ModelViewMatrix * gl_Vertex;
gl_Position = ftransform();
gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
//orthoTexCoord = orthophotoTexCoord;
normal = gl_NormalMatrix * gl_Normal;
//nvec = (gl_NormalMatrix * gl_Normal).xy;
// Temporary value:
ground_tex_coord = gl_TexCoord[0].st;
// 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 = (fg_zUpTransform * vec4(gl_Vertex - 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(relPos.z,100.0);
scattering = ground_scattering + (1.0 - ground_scattering) * smoothstep(hazeLayerAltitude -100.0, hazeLayerAltitude + 100.0, vertex_alt);
// Required for water calculations
lightdir = normalize(vec3(fg_zUpTransform * vec4(gl_ModelViewMatrixInverse * gl_LightSource[0].position)));
waterTex4 = vec4( ecPosition.xzy, 0.0 );
vec4 t1 = vec4(0.0, osg_SimulationTime * 0.005217, 0.0, 0.0);
vec4 t2 = vec4(0.0, osg_SimulationTime * -0.0012, 0.0, 0.0);
float Angle;
float windFactor = sqrt(WindE * WindE + WindN * WindN) * 0.05;
if (WindN == 0.0 && WindE == 0.0) {
Angle = 0.0;
} else {
Angle = atan(-WindN, WindE) - atan(1.0);
}
mat4 RotationMatrix;
createRotationMatrix(Angle, RotationMatrix);
waterTex1 = gl_MultiTexCoord0 * RotationMatrix - t1 * windFactor;
waterTex2 = gl_MultiTexCoord0 * RotationMatrix - t2 * windFactor;
// 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;
//earthShade = 1.0;
// 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;
// Water specular calculations
specular_light.b = light_func(lightArg, 1.330e-05, 0.264, 3.827, 1.08e-05, 1.0);
specular_light.g = light_func(lightArg, 3.931e-06, 0.264, 3.827, 7.93e-06, 1.0);
specular_light.r = light_func(lightArg, 8.305e-06, 0.161, 3.827, 3.04e-05, 1.0);
specular_light = max(specular_light * scattering, vec3 (0.05, 0.05, 0.05));
intensity = length(specular_light.rgb);
specular_light.rgb = intensity * normalize(mix(specular_light.rgb, shadedFogColor, 1.0 -smoothstep(0.1, 0.6,ground_scattering) ));
specular_light.rgb = intensity * normalize(mix(specular_light.rgb, shadedFogColor, 1.0 -smoothstep(0.5, 0.7,earthShade)));
// 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) ));
}
// directional scattering for low sun
if (lightArg < 10.0) {
mie_angle = (0.5 * dot(normalize(relPos), lightdir) ) + 0.5;
} else {
mie_angle = 1.0;
}
// 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);
specular_light = vec3 (1.0, 1.0, 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;
specular_light.b = 0.78 + lightArg * 0.21;
specular_light.g = 0.907 + lightArg * 0.091;
specular_light.r = 0.904 + lightArg * 0.092;
}
light_diffuse = light_diffuse * scattering;
specular_light = specular_light * 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);
specular_light.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
light_diffuse_comp = light_diffuse;
//Testing phase code: ambient colours are not sent to fragement shader yet.
// They are all default except for water/ocean etc. currently
// Emission is all set to the default of vec4(0.0, 0.0, 0.0, 1.0)
//To do: Fix this once ambient colour becomes available in the fragment shaders.
//const vec4 ambient_color = vec4(0.2, 0.2, 0.2, 1.0);
const vec4 ambient_color = vec4(1.0);
vec4 constant_term = ambient_color * (gl_LightModel.ambient + light_ambient);
light_diffuse_comp.a = yprime_alt;
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);
}