dda21aeae1
Implement a simple water shader for HDR. Largely created from the non-HDR WS3.0 water shader, but only generating a fragment normal. Notes: - Water color is a constant in the shader, and set by eye only. - foam etc is not yet implemented. - at very low altitudes the shader breaks down somewhat.
247 lines
8.6 KiB
GLSL
247 lines
8.6 KiB
GLSL
// SPDX-FileCopyrightText: (C) 2024 Stuart Buchanan stuart13@gmail.com
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// SPDX-License-Identifier: GPL-2.0-or-later
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// Helper functions for WS30 HDR water implementation
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#version 330 core
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// Hardcoded indexes into the texture atlas
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const int ATLAS_INDEX_WATER = 0;
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const int ATLAS_INDEX_WATER_REFLECTION = 1;
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const int ATLAS_INDEX_WAVES_VERT10_NM = 2;
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const int ATLAS_INDEX_WATER_SINE_NMAP = 3;
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const int ATLAS_INDEX_WATER_REFLECTION_GREY = 4;
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const int ATLAS_INDEX_SEA_FOAM = 5;
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const int ATLAS_INDEX_PERLIN_NOISE_NM = 6;
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const int ATLAS_INDEX_OCEAN_DEPTH = 7;
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const int ATLAS_INDEX_GLOBAL_COLORS = 8;
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const int ATLAS_INDEX_PACKICE_OVERLAY = 9;
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// WS30 uniforms
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uniform sampler2DArray atlas;
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uniform float fg_tileWidth;
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uniform float fg_tileHeight;
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// Water.eff uniforms
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uniform float osg_SimulationTime;
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uniform float WindN;
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uniform float WindE;
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uniform float WaveFreq;
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uniform float WaveAmp;
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uniform float WaveSharp;
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uniform float WaveAngle;
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uniform float WaveFactor;
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/////// functions /////////
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void rotationmatrix(in float angle, out mat4 rotmat)
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{
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rotmat = mat4( cos( angle ), -sin( angle ), 0.0, 0.0,
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sin( angle ), cos( angle ), 0.0, 0.0,
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0.0 , 0.0 , 1.0, 0.0,
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0.0 , 0.0 , 0.0, 1.0 );
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}
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// wave functions ///////////////////////
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struct Wave {
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float freq; // 2*PI / wavelength
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float amp; // amplitude
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float phase; // speed * 2*PI / wavelength
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vec2 dir;
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};
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Wave wave0 = Wave(1.0, 1.0, 0.5, vec2(0.97, 0.25));
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Wave wave1 = Wave(2.0, 0.5, 1.3, vec2(0.97, -0.25));
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Wave wave2 = Wave(1.0, 1.0, 0.6, vec2(0.95, -0.3));
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Wave wave3 = Wave(2.0, 0.5, 1.4, vec2(0.99, 0.1));
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float evaluateWave(in Wave w, in vec2 pos, in float t) {
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return w.amp * sin( dot(w.dir, pos) * w.freq + t * w.phase);
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}
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// derivative of wave function
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float evaluateWaveDeriv(in Wave w, in vec2 pos, in float t) {
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return w.freq * w.amp * cos( dot(w.dir, pos)*w.freq + t*w.phase);
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}
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// sharp wave functions
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float evaluateWaveSharp(in Wave w, in vec2 pos, in float t, in float k) {
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return w.amp * pow(sin( dot(w.dir, pos)*w.freq + t*w.phase)* 0.5 + 0.5 , k);
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}
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float evaluateWaveDerivSharp(in Wave w, in vec2 pos, in float t, in float k) {
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return k*w.freq*w.amp * pow(sin( dot(w.dir, pos)*w.freq + t*w.phase)* 0.5 + 0.5 , k - 1) * cos( dot(w.dir, pos)*w.freq + t*w.phase);
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}
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void sumWaves(in float angle, in float dangle, in float windScale, in float factor, in vec4 waterTex1, out float ddx, float ddy) {
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mat4 RotationMatrix;
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float deriv;
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vec4 P = waterTex1 * 1024;
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rotationmatrix(radians(angle + dangle * windScale + 0.6 * sin(P.x * factor)), RotationMatrix);
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P *= RotationMatrix;
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P.y += evaluateWave(wave0, P.xz, osg_SimulationTime);
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deriv = evaluateWaveDeriv(wave0, P.xz, osg_SimulationTime );
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ddx = deriv * wave0.dir.x;
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ddy = deriv * wave0.dir.y;
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P.y += evaluateWaveSharp(wave2, P.xz, osg_SimulationTime, WaveSharp);
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deriv = evaluateWaveDerivSharp(wave2, P.xz, osg_SimulationTime, WaveSharp);
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ddx += deriv * wave2.dir.x;
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ddy += deriv * wave2.dir.y;
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}
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vec3 generateWaterNormal(in vec2 texCoords)
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{
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float tileScale = 1 / (fg_tileHeight + fg_tileWidth) / 2.0;
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vec4 sca = vec4(0.005, 0.005, 0.005, 0.005) * tileScale;
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vec4 sca2 = vec4(0.02, 0.02, 0.02, 0.02) * tileScale;
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vec4 tscale = vec4(0.25, 0.25, 0.25, 0.25) / 10000.0 * tileScale;
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vec3 Normal = vec3 (0.0, 0.0, 1.0);
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const float water_shininess = 240.0;
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float windEffect = sqrt( WindE*WindE + WindN*WindN ) * 0.6; //wind speed in kt
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float windScale = 15.0/(3.0 + windEffect); //wave scale
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float windEffect_low = 0.3 + 0.7 * smoothstep(0.0, 5.0, windEffect); //low windspeed wave filter
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float waveRoughness = 0.01 + smoothstep(0.0, 40.0, windEffect); //wave roughness filter
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vec4 t1 = vec4(0.0, osg_SimulationTime * 0.005217, 0.0, 0.0);
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vec4 t2 = vec4(0.0, osg_SimulationTime * -0.0012, 0.0, 0.0);
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float Angle;
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float windFactor = sqrt(WindE * WindE + WindN * WindN) * 0.05;
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if (WindN == 0.0 && WindE == 0.0) {
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Angle = 0.0;
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} else {
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Angle = atan(-WindN, WindE) - atan(1.0);
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}
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mat4 RotationMatrix;
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rotationmatrix(Angle, RotationMatrix);
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vec4 waterTex1 = vec4(texCoords.s, texCoords.t, 0.0, 0.0) * RotationMatrix - t1 * windFactor;
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rotationmatrix(Angle, RotationMatrix);
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vec4 waterTex2 = vec4(texCoords.s, texCoords.t, 0.0, 0.0) * RotationMatrix - t2 * windFactor;
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float mixFactor = 0.2 + 0.02 * smoothstep(0.0, 50.0, windEffect);
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mixFactor = clamp(mixFactor, 0.3, 0.8);
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// sine waves
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float ddx, ddx1, ddx2, ddx3, ddy, ddy1, ddy2, ddy3;
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float angle;
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ddx = 0.0, ddy = 0.0;
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ddx1 = 0.0, ddy1 = 0.0;
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ddx2 = 0.0, ddy2 = 0.0;
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ddx3 = 0.0, ddy3 = 0.0;
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angle = 0.0;
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wave0.freq = WaveFreq ;
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wave0.amp = WaveAmp;
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wave0.dir = vec2 (0.0, 1.0); //vec2(cos(radians(angle)), sin(radians(angle)));
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angle -= 45;
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wave1.freq = WaveFreq * 2.0 ;
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wave1.amp = WaveAmp * 1.25;
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wave1.dir = vec2(0.70710, -0.7071); //vec2(cos(radians(angle)), sin(radians(angle)));
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angle += 30;
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wave2.freq = WaveFreq * 3.5;
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wave2.amp = WaveAmp * 0.75;
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wave2.dir = vec2(0.96592, -0.2588);// vec2(cos(radians(angle)), sin(radians(angle)));
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angle -= 50;
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wave3.freq = WaveFreq * 3.0 ;
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wave3.amp = WaveAmp * 0.75;
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wave3.dir = vec2(0.42261, -0.9063); //vec2(cos(radians(angle)), sin(radians(angle)));
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// sum waves
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sumWaves(WaveAngle, -1.5, windScale, WaveFactor, waterTex1, ddx, ddy);
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sumWaves(WaveAngle, 1.5, windScale, WaveFactor, waterTex1, ddx1, ddy1);
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//reset the waves
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angle = 0.0;
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float waveamp = WaveAmp * 0.75;
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wave0.freq = WaveFreq ;
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wave0.amp = waveamp;
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wave0.dir = vec2 (0.0, 1.0); //vec2(cos(radians(angle)), sin(radians(angle)));
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angle -= 20;
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wave1.freq = WaveFreq * 2.0 ;
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wave1.amp = waveamp * 1.25;
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wave1.dir = vec2(0.93969, -0.34202);// vec2(cos(radians(angle)), sin(radians(angle)));
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angle += 35;
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wave2.freq = WaveFreq * 3.5;
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wave2.amp = waveamp * 0.75;
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wave2.dir = vec2(0.965925, 0.25881); //vec2(cos(radians(angle)), sin(radians(angle)));
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angle -= 45;
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wave3.freq = WaveFreq * 3.0 ;
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wave3.amp = waveamp * 0.75;
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wave3.dir = vec2(0.866025, -0.5); //vec2(cos(radians(angle)), sin(radians(angle)));
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// end sine stuff
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vec2 st = vec2(waterTex2 * tscale * windScale);
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vec4 disdis = texture(atlas, vec3(st, ATLAS_INDEX_WATER_SINE_NMAP)) * 2.0 - 1.0;
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//normalmaps
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st = vec2(waterTex1 + disdis * sca2) * windScale;
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vec4 nmap = texture(atlas, vec3(st, ATLAS_INDEX_WAVES_VERT10_NM)) * 2.0 - 1.0;
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vec4 nmap1 = texture(atlas, vec3(st, ATLAS_INDEX_PERLIN_NOISE_NM)) * 2.0 - 1.0;
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rotationmatrix(radians(3.0 * sin(osg_SimulationTime * 0.0075)), RotationMatrix);
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st = vec2(waterTex2 * RotationMatrix * tscale) * windScale;
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nmap += texture(atlas, vec3(st, ATLAS_INDEX_WAVES_VERT10_NM)) * 2.0 - 1.0;
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nmap *= windEffect_low;
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nmap1 *= windEffect_low;
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// mix water and noise, modulated by factor
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vec4 vNorm = normalize(mix(nmap, nmap1, mixFactor) * waveRoughness);
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vNorm.r += ddx + ddx1 + ddx2 + ddx3;
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st = vec2(waterTex1 + disdis * sca2) * windScale;
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vec3 N0 = vec3(texture(atlas, vec3(st, ATLAS_INDEX_WAVES_VERT10_NM))) * 2.0 - 1.0;
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st = vec2(waterTex1 + disdis * sca) * windScale;
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vec3 N1 = vec3(texture(atlas, vec3(st, ATLAS_INDEX_PERLIN_NOISE_NM))) * 2.0 - 1.0;
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st = vec2(waterTex1 * tscale) * windScale;
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N0 += vec3(texture(atlas, vec3(st, ATLAS_INDEX_WAVES_VERT10_NM))) * 2.0 - 1.0;
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N1 += vec3(texture(atlas, vec3(st, ATLAS_INDEX_PERLIN_NOISE_NM))) * 2.0 - 1.0;
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rotationmatrix(radians(2.0 * sin(osg_SimulationTime * 0.005)), RotationMatrix);
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st = vec2(waterTex2 * RotationMatrix * (tscale + sca2)) * windScale;
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N0 += vec3(texture(atlas, vec3(st, ATLAS_INDEX_WAVES_VERT10_NM))) * 2.0 - 1.0;
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N1 += vec3(texture(atlas, vec3(st, ATLAS_INDEX_PERLIN_NOISE_NM))) * 2.0 - 1.0;
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rotationmatrix(radians(-4.0 * sin(osg_SimulationTime * 0.003)), RotationMatrix);
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st = vec2(waterTex1 * RotationMatrix + disdis * sca2) * windScale;
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N0 += vec3(texture(atlas, vec3(st, ATLAS_INDEX_WAVES_VERT10_NM))) * 2.0 - 1.0;
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st = vec2(waterTex1 * RotationMatrix + disdis * sca) * windScale;
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N1 += vec3(texture(atlas, vec3(st, ATLAS_INDEX_PERLIN_NOISE_NM))) * 2.0 - 1.0;
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N0 *= windEffect_low;
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N1 *= windEffect_low;
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N0.r += (ddx + ddx1 + ddx2 + ddx3);
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N0.g += (ddy + ddy1 + ddy2 + ddy3);
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vec3 N = normalize(mix(Normal + N0, Normal + N1, mixFactor) * waveRoughness);
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// From observation, the normal is generated in the wrong direction, resulting
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// in specular highlights facing away from the Sun. This matrix attempts to correct it
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mat3 rotMat = mat3(0.0, 0.0, 1.0,
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0.0, 1.0, 0.0,
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1.0, 0.0, 0.0);
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N = N * rotMat;
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return N;
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}
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