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102 行
3.3 KiB
102 行
3.3 KiB
#ifndef GERSTNER_WAVES_INCLUDED
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#define GERSTNER_WAVES_INCLUDED
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uniform uint _WaveCount; // how many waves, set via the water component
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float _GlobalTime; // global scene time
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struct Wave
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{
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half amplitude;
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half direction;
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half wavelength;
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half2 origin;
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half omni;
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};
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#if defined(USE_STRUCTURED_BUFFER)
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StructuredBuffer<Wave> _WaveDataBuffer;
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#else
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half4 waveData[20]; // 0-9 amplitude, direction, wavelength, omni, 10-19 origin.xy
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#endif
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struct WaveStruct
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{
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float3 position;
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float3 normal;
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};
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WaveStruct GerstnerWave(half2 pos, float waveCountMulti, half amplitude, half direction, half wavelength, half omni, half2 omniPos)
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{
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WaveStruct waveOut;
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////////////////////////////////wave value calculations//////////////////////////
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half3 wave = 0; // wave vector
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half w = 6.28318 / wavelength; // 2pi over wavelength(hardcoded)
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half wSpeed = sqrt(9.8 * w); // frequency of the wave based off wavelength
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half peak = 1; // peak value, 1 is the sharpest peaks
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half qi = peak / (amplitude * w * _WaveCount);
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direction = radians(direction); // convert the incoming degrees to radians, for directional waves
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half2 dirWaveInput = half2(sin(direction), cos(direction)) * (1 - omni);
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half2 omniWaveInput = (pos - omniPos) * omni;
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half2 windDir = normalize(dirWaveInput + omniWaveInput); // calculate wind direction
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half dir = dot(windDir, pos - (omniPos * omni)); // calculate a gradient along the wind direction
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////////////////////////////position output calculations/////////////////////////
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half calc = dir * w + -_GlobalTime * wSpeed; // the wave calculation
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half cosCalc = cos(calc); // cosine version(used for horizontal undulation)
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half sinCalc = sin(calc); // sin version(used for vertical undulation)
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// calculate the offsets for the current point
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wave.xz = qi * amplitude * windDir.xy * cosCalc;
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wave.y = (((sinCalc * 0.5 + 0.5) * amplitude)) * waveCountMulti;// the height is divided by the number of waves
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////////////////////////////normal output calculations/////////////////////////
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half wa = w * amplitude;
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// normal vector
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half3 n = half3(-(windDir.xy * wa * cosCalc),
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1-(qi * wa * sinCalc));
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////////////////////////////////assign to output///////////////////////////////
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waveOut.position = wave * saturate(amplitude * 10000);
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waveOut.normal = (n * waveCountMulti) * amplitude;
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return waveOut;
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}
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inline void SampleWaves(float3 position, half opacity, out WaveStruct waveOut)
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{
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half2 pos = position.xz;
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WaveStruct waves[10];
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waveOut.position = 0;
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waveOut.normal = 0;
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half waveCountMulti = 1.0 / _WaveCount;
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UNITY_LOOP
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for(uint i = 0; i < _WaveCount; i++)
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{
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#if defined(USE_STRUCTURED_BUFFER)
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waves[i] = GerstnerWave(pos,
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waveCountMulti,
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_WaveDataBuffer[i].amplitude * opacity,
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_WaveDataBuffer[i].direction,
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_WaveDataBuffer[i].wavelength,
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_WaveDataBuffer[i].omni,
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_WaveDataBuffer[i].origin); // calculate the wave
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#else
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waves[i] = GerstnerWave(pos,
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waveCountMulti,
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waveData[i].x * opacity,
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waveData[i].y,
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waveData[i].z,
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waveData[i].w,
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waveData[i + 10].xy); // calculate the wave
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#endif
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waveOut.position += waves[i].position; // add the position
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waveOut.normal += waves[i].normal; // add the normal
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}
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}
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#endif // GERSTNER_WAVES_INCLUDED
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