// WS30 FRAGMENT SHADER
// -*-C++-*-
#version 130
#extension GL_EXT_texture_array : enable
// written by Thorsten Renk, Oct 2011, based on default.frag
//////////////////////////////////////////////////////////////////
// TEST PHASE TOGGLES AND CONTROLS
//
// Development tools:
// Reduce haze to almost zero, while preserving lighting. Useful for observing distant tiles.
// Keeps the calculation overhead. This can be used for profiling.
// Possible values: 0:Normal, 1:Reduced haze.
const int reduce_haze_without_removing_calculation_overhead = 0;
// Remove haze and lighting and shows just the texture.
// Useful for checking texture rendering and scenery.
// The compiler will likely optimise out the haze and lighting calculations.
// Possible values: 0:Normal, 1:Just the texture.
const int remove_haze_and_lighting = 0;
//
// End of test phase controls
//////////////////////////////////////////////////////////////////
// Ambient term comes in gl_Color.rgb.
varying vec4 light_diffuse_comp;
varying vec3 normal;
varying vec3 relPos;
uniform sampler2D landclass;
uniform sampler2DArray textureArray;
varying float yprime_alt;
varying float mie_angle;
varying vec4 ecPosition;
uniform float visibility;
uniform float avisibility;
uniform float scattering;
uniform float terminator;
uniform float terrain_alt;
uniform float hazeLayerAltitude;
uniform float overcast;
uniform float eye_alt;
uniform float cloud_self_shading;
// Passed from VPBTechnique, not the Effect
uniform int tile_level;
uniform float tile_width;
uniform float tile_height;
uniform bool photoScenery;
uniform vec4 dimensionsArray[128];
uniform vec4 ambientArray[128];
uniform vec4 diffuseArray[128];
uniform vec4 specularArray[128];
const float EarthRadius = 5800000.0;
const float terminator_width = 200000.0;
float alt;
float eShade;
float fog_func (in float targ, in float alt);
vec3 get_hazeColor(in float light_arg);
vec3 filter_combined (in vec3 color) ;
float shadow_func (in float x, in float y, in float noise, in float dist);
float DotNoise2D(in vec2 coord, in float wavelength, in float fractionalMaxDotSize, in float dot_density);
float Noise2D(in vec2 coord, in float wavelength);
float Noise3D(in vec3 coord, in float wavelength);
float SlopeLines2D(in vec2 coord, in vec2 gradDir, in float wavelength, in float steepness);
float Strata3D(in vec3 coord, in float wavelength, in float variation);
float fog_func (in float targ, in float alt);
float rayleigh_in_func(in float dist, in float air_pollution, in float avisibility, in float eye_alt, in float vertex_alt);
float alt_factor(in float eye_alt, in float vertex_alt);
float light_distance_fading(in float dist);
float fog_backscatter(in float avisibility);
vec3 rayleigh_out_shift(in vec3 color, in float outscatter);
vec3 get_hazeColor(in float light_arg);
vec3 searchlight();
vec3 landing_light(in float offset, in float offsetv);
vec3 filter_combined (in vec3 color) ;
float getShadowing();
vec3 getClusteredLightsContribution(vec3 p, vec3 n, vec3 texel);
// Not used
float luminance(vec3 color)
{
return dot(vec3(0.212671, 0.715160, 0.072169), color);
}
//////////////////////////
// Test-phase code:
// These should be sent as uniforms
// Tile dimensions in meters
// vec2 tile_size = vec2(tile_width , tile_height);
// Testing: texture coords are sent flipped right now:
// Note tile_size is defined in the shader include: ws30-landclass-search-functions.frag.
// vec2 tile_size = vec2(tile_height , tile_width);
// From noise.frag
float rand2D(in vec2 co);
// These functions, and other function they depend on, are defined
// in ws30-ALS-landclass-search.frag.
// Create random landclasses without a texture lookup to stress test.
// Each square of square_size in m is assigned a random landclass value.
int get_random_landclass(in vec2 co, in vec2 tile_size);
// Lookup a ground texture at a point based on the landclass at that point, without visible
// seams at coordinate discontinuities or at landclass boundaries where texture are switched.
// The partial derivatives of the tile_coord at the fragment is needed to adjust for
// the stretching of different textures, so that the correct mip-map level is looked
// up and there are no seams.
vec4 lookup_ground_texture_array(in vec2 tile_coord, in int landclass_id, in vec2 dx, in vec2 dy);
// Look up the landclass id [0 .. 255] for this particular fragment.
// Lookup id of any neighbouring landclass that is within the search distance.
// Searches are performed in upto 4 directions right now, but only one landclass is looked up
// Create a mix factor werighting the influences of nearby landclasses
void get_landclass_id(in vec2 tile_coord,
const in float landclass_texel_size_m, in vec2 dx, in vec2 dy,
out int landclass_id, out ivec4 neighbor_landclass_ids,
out int num_unique_neighbors,out vec4 mix_factor
);
// End Test-phase code
////////////////////////
void main()
{
vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
// this is taken from default.frag
vec3 n;
float NdotL, NdotHV, fogFactor;
vec3 lightDir = gl_LightSource[0].position.xyz;
vec3 halfVector = gl_LightSource[0].halfVector.xyz;
vec4 texel;
vec4 fragColor;
vec4 specular = vec4(0.0);
float intensity;
// Oct 27 2021:
// Geometry is in the form of roughly rectangular 'tiles'
// with a mesh forming a grid with regular spacing.
// Each vertex in the mesh is given an elevation
// Tile dimensions in m
// Testing: created from two float uniforms in global scope. Should be sent as a vec2
// vec2 tile_size
// Tile texture coordinates range [0..1] over the tile 'rectangle'
vec2 tile_coord = gl_TexCoord[0].st;
// Test phase: Constants and toggles for transitions between landlcasses are defined at
// the top of this file.
// Look up the landclass id [0 .. 255] for this particular fragment
// and any neighbouring landclass that is close.
// Each tile has 1 texture containing landclass ids stetched over it.
// Landclass for current fragment, and up-to 4 neighboring landclasses - 2 used currently
int lc;
ivec4 lc_n;
int num_unique_neighbors = 0;
// Mix factor of base textures for 2 neighbour landclass(es)
vec4 mfact;
const float landclass_texel_size_m = 25.0;
// Partial derivatives of s and t for this fragment,
// with respect to window (screen space) x and y axes.
// Used to pick mipmap LoD levels, and turn off unneeded procedural detail
vec2 dx = dFdx(tile_coord);
vec2 dy = dFdy(tile_coord);
get_landclass_id(tile_coord, landclass_texel_size_m, dx, dy,
lc, lc_n, num_unique_neighbors, mfact);
// The landclass id is used to index into arrays containing
// material parameters and textures for the landclass as
// defined in the regional definitions
float index = float(lc)/512.0;
vec4 index_n = vec4(lc_n)/512.0;
// Material properties.
vec4 mat_diffuse, mat_ambient, mat_specular;
float mat_shininess;
if (photoScenery) {
mat_ambient = vec4(1.0,1.0,1.0,1.0);
mat_diffuse = vec4(1.0,1.0,1.0,1.0);
mat_specular = vec4(0.1, 0.1, 0.1, 1.0);
mat_shininess = 1.2;
texel = texture(landclass, vec2(gl_TexCoord[0].s, 1.0 - gl_TexCoord[0].t));
} else {
// Color Mode is always AMBIENT_AND_DIFFUSE, which means
// using a base colour of white for ambient/diffuse,
// rather than the material color from ambientArray/diffuseArray.
mat_ambient = vec4(1.0,1.0,1.0,1.0);
mat_diffuse = vec4(1.0,1.0,1.0,1.0);
mat_specular = specularArray[lc];
mat_shininess = dimensionsArray[lc].z;
// Look up ground textures by indexing into the texture array.
// Different textures are stretched along the ground to different
// lengths along each axes as set by <xsize> and <ysize>
// regional definitions parameters
// Look up texture coordinates and scale of ground textures
// Landclass for this fragment
texel = lookup_ground_texture_array(tile_coord, lc, dx, dy);
// Mix texels - to work consistently it needs a more preceptual interpolation than mix()
if (num_unique_neighbors != 0)
{
// Closest neighbor landclass
vec4 texel_closest = lookup_ground_texture_array(tile_coord, lc_n[0], dx, dy);
// Neighbor contributions
vec4 texel_nc=texel_closest;
if (num_unique_neighbors > 1)
{
// 2nd Closest neighbor landclass
vec4 texel_2nd_closest = lookup_ground_texture_array(tile_coord, lc_n[1],
dx, dy);
texel_nc = mix(texel_closest, texel_2nd_closest, mfact[1]);
}
texel = mix(texel, texel_nc, mfact[0]);
}
}
vec4 color = mat_ambient * (gl_LightModel.ambient + gl_LightSource[0].ambient);
// Testing code:
// Use rlc even when looking up textures to recreate the extra performance hit
// so any performance difference between the two is due to the texture lookup
// color = color+0.00001*float(get_random_landclass(tile_coord.st, tile_size));
float effective_scattering = min(scattering, cloud_self_shading);
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(normal);
NdotL = dot(n, lightDir);
vec4 diffuse_term = light_diffuse_comp * mat_diffuse;
if (NdotL > 0.0) {
float shadowmap = getShadowing();
vec4 diffuse_term = light_diffuse_comp * mat_diffuse;
color += diffuse_term * NdotL * shadowmap;
NdotHV = max(dot(n, halfVector), 0.0);
if (mat_shininess > 0.0)
specular.rgb = (mat_specular.rgb
* light_specular.rgb
* pow(NdotHV, gl_FrontMaterial.shininess)
* shadowmap);
}
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);
// Testing code: mix with green to show values of variables at each point
//vec4 green = vec4(0.0, 0.5, 0.0, 0.0);
//texel = mix(texel, green, (mfact[2]));
fragColor = color * texel + specular;
fragColor.rgb += getClusteredLightsContribution(ecPosition.xyz, n, texel.rgb);
// here comes the terrain haze model
float delta_z = hazeLayerAltitude - eye_alt;
float dist = length(relPos);
float mvisibility = min(visibility,avisibility);
if (dist > 0.04 * mvisibility)
{
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,mvisibility) * 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;
if (visibility < avisibility)
{
transmission_arg = transmission_arg + (distance_in_layer/visibility);
// this combines the Weber-Fechner intensity
eqColorFactor = 1.0 - 0.1 * delta_zv/visibility - (1.0 -effective_scattering);
}
else
{
transmission_arg = transmission_arg + (distance_in_layer/avisibility);
// this combines the Weber-Fechner intensity
eqColorFactor = 1.0 - 0.1 * delta_zv/avisibility - (1.0 -effective_scattering);
}
transmission = fog_func(transmission_arg, alt);
// 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 = get_hazeColor(lightArg);
// now dim the light for haze
eShade = 1.0 - 0.9 * smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt);
// Mie-like factor
if (lightArg < 10.0)
{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* shadedFogColor, 1.0 -smoothstep(0.25, fade_out,eShade) ));
// change haze color to blue hue for strong fogging
//intensity = length(hazeColor);
hazeColor = intensity * normalize(mix(hazeColor, shadedFogColor, (1.0-smoothstep(0.5,0.9,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));
// don't let the light fade out too rapidly
lightArg = (terminator + 200000.0)/100000.0;
float minLightIntensity = min(0.2,0.16 * lightArg + 0.5);
vec3 minLight = minLightIntensity * vec3 (0.2, 0.3, 0.4);
hazeColor *= eqColorFactor * eShade;
hazeColor.rgb = max(hazeColor.rgb, minLight.rgb);
// determine the right mix of transmission and haze
// Testing phase controls
if (reduce_haze_without_removing_calculation_overhead == 1)
{
transmission = 1.0 - (transmission/1000000.0);
}
fragColor.rgb = mix(hazeColor, fragColor.rgb,transmission);
}
fragColor.rgb = filter_combined(fragColor.rgb);
gl_FragColor = fragColor;
// Testing phase controls:
if (remove_haze_and_lighting == 1)
{
gl_FragColor = texel;
}
}