435 lines
16 KiB
C++
435 lines
16 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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//////////////////////////////////////////////////////////////////
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// TEST PHASE TOGGLES AND CONTROLS
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//
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// Remove haze and lighting and shows just the texture.
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// Useful for checking texture rendering and scenery.
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// The compiler will likely optimise out the haze and lighting calculations.
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// Possible values: 0:Normal, 1:Just the texture.
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const int remove_haze_and_lighting = 0;
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// Randomise texture lookups for 5 non-base textures e.g. mix_texture, detaile_texture etc.
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// Each landclass is assigned 5 random textures from the ground texture array.
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// This simulates a worst case possible texture lookup scenario, without needing access to material parameters.
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// This does not simulate multiple texture sets, of which there may be up-to 4.
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// The performance will likely be worse than in a real situation - there might be fewer textures
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// for mix, detail and other textures. This might be easier on the GPUs texture caches.
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// Possible values: 0: disabled (default),
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// 1: enabled,
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// 2: remove texture array lookups for 5 textures - only base texture + neighbour base textures
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const int randomise_texture_lookups = 0;
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// Use built-in water shader. Use for testing impact of ws30-water.frag
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const int water_shader = 1;
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//
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// End of test phase controls
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//////////////////////////////////////////////////////////////////
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// Ambient term comes in gl_Color.rgb.
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varying vec4 light_diffuse_comp;
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varying vec3 normal;
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varying vec3 relPos;
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varying vec2 ground_tex_coord;
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varying vec3 worldPos;
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varying vec2 rawPos;
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varying vec3 ecViewdir;
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varying vec2 grad_dir;
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varying vec4 ecPosition;
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varying float steepness;
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uniform sampler2D landclass;
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uniform sampler2DArray textureArray;
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uniform sampler2D perlin;
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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 snowlevel;
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uniform float dust_cover_factor;
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uniform float lichen_cover_factor;
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uniform float wetness;
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uniform float fogstructure;
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uniform float snow_thickness_factor;
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uniform float cloud_self_shading;
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uniform float season;
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uniform float air_pollution;
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uniform float WindE;
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uniform float WindN;
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uniform float landing_light1_offset;
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uniform float landing_light2_offset;
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uniform float landing_light3_offset;
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uniform float osg_SimulationTime;
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uniform int wind_effects;
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uniform int cloud_shadow_flag;
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uniform int use_searchlight;
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uniform int use_landing_light;
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uniform int use_alt_landing_light;
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// Testing code: Currently hardcoded to 2000, to allow noise functions to run while waiting for landclass lookup(s)
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uniform int swatch_size; //in metres, typically 1000 or 2000
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// Passed from VPBTechnique, not the Effect
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uniform float fg_tileWidth;
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uniform float fg_tileHeight;
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uniform bool fg_photoScenery;
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// Material parameters, from material definitions and effect defaults, for each landclass.
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// xsize and ysize
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uniform vec4 fg_dimensionsArray[128];
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// RGBA ambient color
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uniform vec4 fg_ambientArray[128];
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// RGBA diffuse color
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uniform vec4 fg_diffuseArray[128];
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// RGBA specular color
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uniform vec4 fg_specularArray[128];
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// Indicies of textures in the ground texture array for different
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// texture slots (grain, gradient, dot, mix, detail) for each landclass
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uniform vec4 fg_textureLookup1[128];
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uniform vec4 fg_textureLookup2[128];
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// Each element of a vec4 contains a different materials parameter.
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uniform vec4 fg_materialParams1[128];
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uniform vec4 fg_materialParams2[128];
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uniform vec4 fg_materialParams3[128];
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// Coastline texture - generated from VPBTechnique
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uniform sampler2D coastline;
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// Sand texture
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uniform sampler2D sand;
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uniform mat4 fg_zUpTransform;
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uniform vec3 fg_modelOffset;
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const float terminator_width = 200000.0;
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float shadow_func (in float x, in float y, in float noise, in float dist);
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float DotNoise2D(in vec2 coord, in float wavelength, in float fractionalMaxDotSize, in float dot_density);
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float Noise2D(in vec2 coord, in float wavelength);
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float Noise3D(in vec3 coord, in float wavelength);
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float SlopeLines2D(in vec2 coord, in vec2 gradDir, in float wavelength, in float steepness);
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float Strata3D(in vec3 coord, in float wavelength, in float variation);
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float fog_func (in float targ, in float alt);
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float rayleigh_in_func(in float dist, in float air_pollution, in float avisibility, in float eye_alt, in float vertex_alt);
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float alt_factor(in float eye_alt, in float vertex_alt);
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float light_distance_fading(in float dist);
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float fog_backscatter(in float avisibility);
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vec3 rayleigh_out_shift(in vec3 color, in float outscatter);
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vec3 get_hazeColor(in float light_arg);
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vec3 searchlight();
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vec3 landing_light(in float offset, in float offsetv);
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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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// a fade function for procedural scales which are smaller than a pixel
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float detail_fade (in float scale, in float angle, in float dist)
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{
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float fade_dist = 2000.0 * scale * angle/max(pow(steepness,4.0), 0.1);
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return 1.0 - smoothstep(0.5 * fade_dist, fade_dist, dist);
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}
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//////////////////////////
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// Test-phase code:
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// These should be sent as uniforms
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// Tile dimensions in meters
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// vec2 tile_size = vec2(fg_tileWidth , fg_tileHeight);
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// Testing: texture coords are sent flipped right now:
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// Note tile_size is defined in the shader include: ws30-landclass-search-functions.frag.
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//vec2 tile_size = vec2(fg_tileHeight , fg_tileWidth);
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// Uniform array lookup functions example:
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// Access data[] as if it was a 1-d array of floats
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// with data sorted as rows of data values for each row of texture variants
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// using index for the relevant value
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/*
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float getFloatFromArrayData(int i)
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{
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int n = int(floor(float(i/4.0)));
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vec4 v4 = someArray[n];
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int index_within_v4 = int(mod(float(i),4.0));
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float value = v4[index_within_v4];
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return value;
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}
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vec4 getVec4FromArrayData(int i)
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{
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return (vec4(getFloatFromArrayData(i), getFloatFromArrayData(i+1), getFloatFromArrayData(i+2), getFloatFromArrayData(i+3)));
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}
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*/
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// From noise.frag
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float rand2D(in vec2 co);
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// Generates a full precision 32 bit random number from 2 seeds
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// as well as 6 random integers between 0 and factor that are rescaled 0.0-1.0
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// by re-using the significant figures from the full precision number.
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// This avoids having to generate 6 random numbers when
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// limited variation is needed: say 6 numbers with 100 levels (i.e between 0 and 100).
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// Seed 2 is incremented so the function can be called again to generate
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// a different set of numbers
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float get6_rand_nums(in float PRNGseed1,
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inout float PRNGseed2, float factor, out float [6] random_integers
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);
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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, in vec2 tile_size);
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// End Test-phase code
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////////////////////////
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// These functions, and other function they depend on, are defined
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// in ws30-ALS-landclass-search.frag.
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// Lookup a ground texture at a point based on the landclass at that point, without visible
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// seams at coordinate discontinuities or at landclass boundaries where texture are switched.
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// The partial derivatives of the tile_coord at the fragment is needed to adjust for
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// the stretching of different textures, so that the correct mip-map level is looked
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// up and there are no seams.
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// Texture types: 0: base texture, 1: grain texture, 2: gradient texture, 3 dot texture,
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// 4: mix texture, 5: detail texture.
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vec4 lookup_ground_texture_array(in int texture_type, in vec2 ground_texture_coord, in int landclass_id,
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in vec4 dFdx_and_dFdy);
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// Look up the landclass id [0 .. 255] for this particular fragment.
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// Lookup id of any neighbouring landclass that is within the search distance.
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// Searches are performed in upto 4 directions right now, but only one landclass is looked up
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// Create a mix factor werighting the influences of nearby landclasses
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void get_landclass_id(in vec2 tile_coord, in vec4 dFdx_and_dFdy,
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out int landclass_id, out ivec4 neighbor_landclass_ids,
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out int num_unique_neighbors,out vec4 mix_factor
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);
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// Look up the texel of the specified texture type (e.g. grain or detail textures) for this fragment
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// and any neighbor texels, then mix.
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vec4 get_mixed_texel(in int texture_type, in vec2 g_texture_coord,
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in int landclass_id, in int num_unique_neighbors,
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in ivec4 neighbor_texel_landclass_ids, in vec4 neighbor_mix_factors,
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in vec4 dFdx_and_dFdy
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);
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// Determine the texel and material parameters for a particular fragment,
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// Taking into account photoscenery etc.
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void get_material(in int landclass,
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in vec2 ground_tex_coord,
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in vec4 dxdy_gc,
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out float mat_shininess,
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out vec4 mat_ambient,
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out vec4 mat_diffuse,
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out vec4 mat_specular,
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out vec4 dxdy,
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out vec2 st
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);
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// Apply the ALS haze model to a specific fragment
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vec4 applyHaze(inout vec4 fragColor,
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inout vec3 hazeColor,
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in vec3 secondary_light,
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in float ct,
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in float hazeLayerAltitude,
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in float visibility,
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in float avisibility,
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in float dist,
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in float lightArg,
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in float mie_angle);
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// Procedurally generate a water texel for this fragment
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vec4 generateWaterTexel();
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void main()
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{
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float yprime_alt = light_diffuse_comp.a;
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//diffuse_term.a = 1.0;
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float mie_angle = gl_Color.a;
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float effective_scattering = min(scattering, cloud_self_shading);
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// distance to fragment
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float dist = length(relPos);
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// angle of view vector with horizon
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float ct = dot(vec3(0.0, 0.0, 1.0), relPos)/dist;
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// float altitude of fragment above sea level
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float msl_altitude = (relPos.z + eye_alt);
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// this is taken from default.frag
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float NdotL, NdotHV, fogFactor;
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vec3 n = normalize(normal);
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vec3 lightDir = gl_LightSource[0].position.xyz;
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vec3 halfVector = normalize(normalize(lightDir) + normalize(ecViewdir));
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vec3 secondary_light = vec3 (0.0,0.0,0.0);
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// Material/texel properties
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float mat_shininess;
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vec2 st;
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vec4 mat_ambient, mat_diffuse, mat_specular, dxdy;
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vec4 texel;
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vec4 snow_texel;
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vec4 detail_texel;
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vec4 mix_texel;
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vec4 grain_texel;
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vec4 dot_texel;
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vec4 gradient_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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// Wind motion of the overlay noise simulating movement of vegetation and loose debris
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vec2 windPos;
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if (wind_effects > 1)
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{
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float windSpeed = length(vec2 (WindE,WindN)) /3.0480;
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// interfering sine wave wind pattern
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float sineTerm = sin(0.35 * windSpeed * osg_SimulationTime + 0.05 * (rawPos.x + rawPos.y));
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sineTerm = sineTerm + sin(0.3 * windSpeed * osg_SimulationTime + 0.04 * (rawPos.x + rawPos.y));
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sineTerm = sineTerm + sin(0.22 * windSpeed * osg_SimulationTime + 0.05 * (rawPos.x + rawPos.y));
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sineTerm = sineTerm/3.0;
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// non-linear amplification to simulate gusts
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sineTerm = sineTerm * sineTerm;//smoothstep(0.2, 1.0, sineTerm);
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// wind starts moving dust and leaves at around 8 m/s
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float timeArg = 0.01 * osg_SimulationTime * windSpeed * smoothstep(8.0, 15.0, windSpeed);
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timeArg = timeArg + 0.02 * sineTerm;
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windPos = vec2 (rawPos.x + WindN * timeArg, rawPos.y + WindE * timeArg);
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}
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else
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{
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windPos = rawPos.xy;
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}
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// get noise at different wavelengths in units of swatch_size
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// original assumed 4km texture.
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// used: 5m, 5m gradient, 10m, 10m gradient: heightmap of the closeup terrain, 10m also snow
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// 50m: detail texel
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// 250m: detail texel
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// 500m: distortion and overlay
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// 1500m: overlay, detail, dust, fog
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// 2000m: overlay, detail, snow, fog
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// Perlin noise
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float noise_10m = Noise2D(rawPos.xy, 10.0);
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float noise_5m = Noise2D(rawPos.xy ,5.0);
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float noise_2m = Noise2D(rawPos.xy ,2.0);
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float noise_1m = Noise2D(rawPos.xy ,1.0);
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float noise_01m = Noise2D(windPos.xy, 0.1);
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// Noise relative to swatch size
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float noise_25m = Noise2D(rawPos.xy, swatch_size*0.000625);
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float noise_50m = Noise2D(rawPos.xy, swatch_size*0.00125);
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float noise_250m = Noise3D(worldPos.xyz,swatch_size*0.0625);
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float noise_500m = Noise3D(worldPos.xyz, swatch_size*0.125);
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float noise_1500m = Noise3D(worldPos.xyz, swatch_size*0.3750);
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float noise_2000m = Noise3D(worldPos.xyz, swatch_size*0.5);
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float noise_4000m = Noise3D(worldPos.xyz, swatch_size);
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float dotnoisegrad_10m;
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// slope noise
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float slopenoise_50m = SlopeLines2D(rawPos.xy, grad_dir, 50.0, steepness);
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float slopenoise_100m = SlopeLines2D(rawPos.xy, grad_dir, 100.0, steepness);
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float snownoise_25m = mix(noise_25m, slopenoise_50m, clamp(3.0*(1.0-steepness),0.0,1.0));
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float snownoise_50m = mix(noise_50m, slopenoise_100m, clamp(3.0*(1.0-steepness),0.0,1.0));
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// get the texels
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float distortion_factor = 1.0;
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vec2 stprime;
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int flag = 1;
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int mix_flag = 1;
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float noise_term;
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float snow_alpha;
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// Oct 27 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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// Testing: created from two float uniforms in global scope. Should be sent as a vec2
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// vec2 tile_size
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// This is a water fragment, so calculate the fragment color procedurally
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// and mix with some sand and cliff colour depending on steepness
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//vec4 steep_texel = lookup_ground_texture_array(2, ground_tex_coord, lc, dxdy_gc); // Uses the same index as the gradient texture, which it is
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//vec4 beach_texel = lookup_ground_texture_array(3, ground_tex_coord, lc, dxdy_gc); // Use the dot texture, which is overloaded to be the beach texture
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// Mix from a rocky texture to beach for steep slopes, which invariably represent the elevation mesh not being perfectly
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// aligned with the landclass mesh.
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// texel = mix(steep_texel, beach_texel, smoothstep(waterline_max_steepness - 0.1, waterline_max_steepness - 0.03, steepness));
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// Mix from the beach into the water, which produces a pleasing translucent shallow water effect.
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//fragColor = mix(texel, generateWaterTexel(), smoothstep(waterline_min_steepness,waterline_max_steepness,steepness));
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fragColor = generateWaterTexel();
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fragColor.rgb += getClusteredLightsContribution(ecPosition.xyz, n, fragColor.rgb);
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float lightArg = (terminator-yprime_alt)/100000.0;
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vec3 hazeColor = get_hazeColor(lightArg);
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// Rayleigh color shift due to out-scattering
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float rayleigh_length = 0.5 * avisibility * (2.5 - 1.9 * air_pollution)/alt_factor(eye_alt, msl_altitude);
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float outscatter = 1.0-exp(-dist/rayleigh_length);
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fragColor.rgb = rayleigh_out_shift(fragColor.rgb,outscatter);
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// Rayleigh color shift due to in-scattering
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float rShade = 1.0 - 0.9 * smoothstep(-terminator_width+ terminator, terminator_width + terminator, yprime_alt + 420000.0);
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//float lightIntensity = length(diffuse_term.rgb)/1.73 * rShade;
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float lightIntensity = length(hazeColor * effective_scattering) * rShade;
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vec3 rayleighColor = vec3 (0.17, 0.52, 0.87) * lightIntensity;
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float rayleighStrength = rayleigh_in_func(dist, air_pollution, avisibility/max(lightIntensity,0.05), eye_alt, msl_altitude);
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fragColor.rgb = mix(fragColor.rgb, rayleighColor,rayleighStrength);
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gl_FragColor = applyHaze(fragColor, hazeColor, secondary_light, ct, hazeLayerAltitude, visibility, avisibility, dist, lightArg, mie_angle);
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// Testing phase controls:
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if (remove_haze_and_lighting == 1)
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{
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gl_FragColor = texel;
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}
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}
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