fc42ef3fe4
Previously only the diffuse term was considered in the fragment shader, leading to very dark scenery and deep shadows. Now the ambient light term is also included making the scenery much closer to the way it should be lit.
324 lines
10 KiB
C++
324 lines
10 KiB
C++
// WS30 FRAGMENT SHADER
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// -*-C++-*-
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#version 130
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#extension GL_EXT_texture_array : enable
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// written by Thorsten Renk, Oct 2011, based on default.frag
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// Ambient term comes in gl_Color.rgb.
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varying vec4 diffuse_term;
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varying vec3 normal;
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varying vec3 relPos;
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uniform sampler2D landclass;
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uniform sampler2DArray textureArray;
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uniform sampler1D dimensionsArray;
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uniform sampler1D diffuseArray;
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uniform sampler1D specularArray;
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uniform sampler2D perlin;
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varying float yprime_alt;
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varying float mie_angle;
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varying vec4 ecPosition;
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uniform float visibility;
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uniform float avisibility;
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uniform float scattering;
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uniform float terminator;
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uniform float terrain_alt;
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uniform float hazeLayerAltitude;
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uniform float overcast;
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uniform float eye_alt;
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uniform float cloud_self_shading;
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// Passed from VPBTechnique, not the Effect
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uniform int tile_level;
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uniform float tile_width;
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uniform float tile_height;
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const float EarthRadius = 5800000.0;
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const float terminator_width = 200000.0;
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float alt;
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float eShade;
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float fog_func (in float targ, in float alt);
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vec3 get_hazeColor(in float light_arg);
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vec3 filter_combined (in vec3 color) ;
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float getShadowing();
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vec3 getClusteredLightsContribution(vec3 p, vec3 n, vec3 texel);
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float luminance(vec3 color)
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{
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return dot(vec3(0.212671, 0.715160, 0.072169), color);
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}
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// Test-phase code:
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float rand2D(in vec2 co);
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// Create random landclasses without a texture lookup to stress test
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// Each square of square_size in m is assigned a random landclass value
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int get_random_landclass(in vec2 co)
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{
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float square_size = 200.0;
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//float r = rand2D( floor(vec2(co.s*tile_width, co.t*tile_height)/square_size) );
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float r = rand2D( floor(vec2(co.s*tile_height, co.t*tile_width)/square_size) );
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int lc = int(r*48.0); // only 48 landclasses mapped so far
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return lc;
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}
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float Noise2D(in vec2 coord, in float wavelength);
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// End Test-phase code
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void main()
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{
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vec3 shadedFogColor = vec3(0.55, 0.67, 0.88);
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// this is taken from default.frag
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vec3 n;
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float NdotL, NdotHV, fogFactor;
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vec3 lightDir = gl_LightSource[0].position.xyz;
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vec3 halfVector = gl_LightSource[0].halfVector.xyz;
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vec4 texel;
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vec4 fragColor;
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vec4 specular = vec4(0.0);
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float intensity;
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// Oct 2021:
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// Geometry is in the form of roughly rectangular 'tiles'
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// with a mesh forming a grid with regular spacing.
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// Each vertex in the mesh is given an elevation
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// Tile dimensions in m
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vec2 tile_size = vec2(tile_width , tile_height);
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// Temp: sizes are the wrong way around currently
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tile_size.xy =tile_size.yx;
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// Tile texture coordinates range [0..1] over the tile 'rectangle'
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vec2 tile_coord = gl_TexCoord[0].st;
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// Look up the landclass id [0 .. 255] for this particular fragment
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// Each tile has 1 texture containing landclass ids stetched over it
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// Testing. Landclass sources: texture or random
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int tlc = int(texture2D(landclass, tile_coord.st).g * 255.0 + 0.5);
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//int rlc = get_random_landclass(tile_coord.st);
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int lc = tlc;
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// The landclass id is used to index into arrays containing
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// material parameters and textures for the landclass as
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// defined in the regional definitions
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float index = float(lc)/512.0;
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float mat_shininess = texture(dimensionsArray, index).z;
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vec4 mat_diffuse = texture(diffuseArray, index);
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vec4 mat_specular = texture(specularArray, index);
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vec4 color = gl_Color + mat_diffuse * NdotL * gl_LightSource[0].diffuse;
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// Testing code:
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// Use rlc even when looking up textures to recreate the extra performance hit
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// so any performance difference between the two is due to the texture lookup
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// color = color+0.00001*float(rlc);
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float effective_scattering = min(scattering, cloud_self_shading);
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vec4 light_specular = gl_LightSource[0].specular;
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// If gl_Color.a == 0, this is a back-facing polygon and the
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// normal should be reversed.
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//n = (2.0 * gl_Color.a - 1.0) * normal;
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n = normalize(normal);
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NdotL = dot(n, lightDir);
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if (NdotL > 0.0) {
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float shadowmap = getShadowing();
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color += diffuse_term * NdotL * shadowmap;
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NdotHV = max(dot(n, halfVector), 0.0);
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if (mat_shininess > 0.0)
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specular.rgb = (mat_specular.rgb
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* light_specular.rgb
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* pow(NdotHV, gl_FrontMaterial.shininess)
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* shadowmap);
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}
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color.a = diffuse_term.a;
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// This shouldn't be necessary, but our lighting becomes very
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// saturated. Clamping the color before modulating by the texture
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// is closer to what the OpenGL fixed function pipeline does.
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color = clamp(color, 0.0, 1.0);
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// Look up ground textures by indexing into the texture array.
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// Different textures are stretched along the ground to different
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// lengths along each axes as set by <xsize> and <ysize>
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// regional definitions parameters
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// Look up stretching dimensions of textures in m - scaled to fit in [0..1], so rescale
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vec2 g_texture_stretch_dim = 10000.0 * texture(dimensionsArray, index).st;
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vec2 g_texture_scale = tile_size.xy / g_texture_stretch_dim.xy;
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// Ground texture coords
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vec2 st = g_texture_scale * tile_coord.st;
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// Rotate texture using the perlin texture as a mask to reduce tiling
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float pnoise1 = texture(perlin, st / 8.0).r;
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float pnoise2 = texture(perlin, - st / 16.0).r;
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//Testing: Non texture alternative
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//float pnoise1 = Noise2D(st, 8.0);
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//float pnoise2 = Noise2D(-st, 16.0);
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if (pnoise1 >= 0.5) st = g_texture_scale.st * tile_coord.ts;
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if (pnoise2 >= 0.5) st = -st;
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texel = texture(textureArray, vec3(st, lc));
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fragColor = color * texel + specular;
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fragColor.rgb += getClusteredLightsContribution(ecPosition.xyz, n, texel.rgb);
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// here comes the terrain haze model
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float delta_z = hazeLayerAltitude - eye_alt;
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float dist = length(relPos);
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float mvisibility = min(visibility,avisibility);
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if (dist > 0.04 * mvisibility)
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{
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alt = eye_alt;
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float transmission;
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float vAltitude;
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float delta_zv;
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float H;
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float distance_in_layer;
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float transmission_arg;
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// angle with horizon
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float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
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// we solve the geometry what part of the light path is attenuated normally and what is through the haze layer
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if (delta_z > 0.0) // we're inside the layer
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{
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if (ct < 0.0) // we look down
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{
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distance_in_layer = dist;
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vAltitude = min(distance_in_layer,mvisibility) * ct;
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delta_zv = delta_z - vAltitude;
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}
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else // we may look through upper layer edge
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{
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H = dist * ct;
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if (H > delta_z) {distance_in_layer = dist/H * delta_z;}
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else {distance_in_layer = dist;}
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vAltitude = min(distance_in_layer,visibility) * ct;
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delta_zv = delta_z - vAltitude;
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}
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}
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else // we see the layer from above, delta_z < 0.0
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{
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H = dist * -ct;
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if (H < (-delta_z)) // we don't see into the layer at all, aloft visibility is the only fading
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{
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distance_in_layer = 0.0;
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delta_zv = 0.0;
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}
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else
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{
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vAltitude = H + delta_z;
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distance_in_layer = vAltitude/H * dist;
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vAltitude = min(distance_in_layer,visibility) * (-ct);
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delta_zv = vAltitude;
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}
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}
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// ground haze cannot be thinner than aloft visibility in the model,
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// so we need to use aloft visibility otherwise
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transmission_arg = (dist-distance_in_layer)/avisibility;
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float eqColorFactor;
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if (visibility < avisibility)
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{
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transmission_arg = transmission_arg + (distance_in_layer/visibility);
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// this combines the Weber-Fechner intensity
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eqColorFactor = 1.0 - 0.1 * delta_zv/visibility - (1.0 -effective_scattering);
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}
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else
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{
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transmission_arg = transmission_arg + (distance_in_layer/avisibility);
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// this combines the Weber-Fechner intensity
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eqColorFactor = 1.0 - 0.1 * delta_zv/avisibility - (1.0 -effective_scattering);
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}
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transmission = fog_func(transmission_arg, alt);
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// there's always residual intensity, we should never be driven to zero
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if (eqColorFactor < 0.2) {eqColorFactor = 0.2;}
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float lightArg = (terminator-yprime_alt)/100000.0;
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vec3 hazeColor = get_hazeColor(lightArg);
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// now dim the light for haze
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eShade = 1.0 - 0.9 * smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt);
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// Mie-like factor
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if (lightArg < 10.0)
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{intensity = length(hazeColor);
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float mie_magnitude = 0.5 * smoothstep(350000.0, 150000.0, terminator-sqrt(2.0 * EarthRadius * terrain_alt));
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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)) );
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}
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// high altitude desaturation of the haze color
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intensity = length(hazeColor);
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hazeColor = intensity * normalize (mix(hazeColor, intensity * vec3 (1.0,1.0,1.0), 0.7* smoothstep(5000.0, 50000.0, alt)));
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// blue hue of haze
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hazeColor.x = hazeColor.x * 0.83;
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hazeColor.y = hazeColor.y * 0.9;
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// additional blue in indirect light
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float fade_out = max(0.65 - 0.3 *overcast, 0.45);
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intensity = length(hazeColor);
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hazeColor = intensity * normalize(mix(hazeColor, 1.5* shadedFogColor, 1.0 -smoothstep(0.25, fade_out,eShade) ));
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// change haze color to blue hue for strong fogging
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//intensity = length(hazeColor);
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hazeColor = intensity * normalize(mix(hazeColor, shadedFogColor, (1.0-smoothstep(0.5,0.9,eqColorFactor))));
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// reduce haze intensity when looking at shaded surfaces, only in terminator region
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float shadow = mix( min(1.0 + dot(normal,lightDir),1.0), 1.0, 1.0-smoothstep(0.1, 0.4, transmission));
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hazeColor = mix(shadow * hazeColor, hazeColor, 0.3 + 0.7* smoothstep(250000.0, 400000.0, terminator));
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// don't let the light fade out too rapidly
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lightArg = (terminator + 200000.0)/100000.0;
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float minLightIntensity = min(0.2,0.16 * lightArg + 0.5);
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vec3 minLight = minLightIntensity * vec3 (0.2, 0.3, 0.4);
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hazeColor *= eqColorFactor * eShade;
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hazeColor.rgb = max(hazeColor.rgb, minLight.rgb);
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// determine the right mix of transmission and haze
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fragColor.rgb = mix(hazeColor, fragColor.rgb,transmission);
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}
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fragColor.rgb = filter_combined(fragColor.rgb);
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gl_FragColor = fragColor;
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}
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