Method Init

SHTest/SampleFramework12/v1.04/Graphics/Skybox.cpp:48–215

}

bool SkyCache::Init(const Float3& sunDirection_, float sunSize, const Float3& groundAlbedo_, float turbidity, bool createCubemap)
{
    Float3 sunDirection = sunDirection_;
    Float3 groundAlbedo = groundAlbedo_;
    sunDirection.y = Saturate(sunDirection.y);
    sunDirection = Float3::Normalize(sunDirection);
    turbidity = Clamp(turbidity, 1.0f, 32.0f);
    groundAlbedo = Saturate(groundAlbedo);
    sunSize = Max(sunSize, 0.01f);

    // Do nothing if we're already up-to-date
    if(Initialized() && sunDirection == SunDirection && groundAlbedo == Albedo && turbidity == Turbidity && SunSize == sunSize)
        return false;

    Shutdown();

    sunDirection.y = Saturate(sunDirection.y);
    sunDirection = Float3::Normalize(sunDirection);
    turbidity = Clamp(turbidity, 1.0f, 32.0f);
    groundAlbedo = Saturate(groundAlbedo);

    float thetaS = AngleBetween(sunDirection, Float3(0, 1, 0));
    float elevation = Pi_2 - thetaS;
    StateR = arhosek_rgb_skymodelstate_alloc_init(turbidity, groundAlbedo.x, elevation);
    StateG = arhosek_rgb_skymodelstate_alloc_init(turbidity, groundAlbedo.y, elevation);
    StateB = arhosek_rgb_skymodelstate_alloc_init(turbidity, groundAlbedo.z, elevation);

    Albedo = groundAlbedo;
    Elevation = elevation;
    SunDirection = sunDirection;
    Turbidity = turbidity;
    SunSize = sunSize;

    // Compute the irradiance of the sun for a surface perpendicular to the sun using monte carlo integration.
    // Note that the solar radiance function provided by the authors of this sky model only works using
    // spectral rendering, so we sample a range of wavelengths and then convert to RGB.
    SampledSpectrum groundAlbedoSpectrum = SampledSpectrum::FromRGB(Albedo, SpectrumType::Reflectance);
    SampledSpectrum solarRadiance;

    // Init the Hosek solar radiance model for all wavelengths
    ArHosekSkyModelState* skyStates[NumSpectralSamples] = { };
    for(int32 i = 0; i < NumSpectralSamples; ++i)
        skyStates[i] = arhosekskymodelstate_alloc_init(thetaS, turbidity, groundAlbedoSpectrum[i]);

    SunIrradiance = Float3(0.0f);

    // Uniformly sample the solid area of the solar disc.
    // Note that we use the *actual* sun size here and not the passed in the sun direction, so that
    // we always end up with the appropriate intensity. This allows changing the size of the sun
    // as it appears in the skydome without actually changing the sun intensity.
    Float3 sunDirX = Float3::Perpendicular(sunDirection);
    Float3 sunDirY = Float3::Cross(sunDirection, sunDirX);
    Float3x3 sunOrientation = Float3x3(sunDirX, sunDirY, sunDirection);

    const uint64 NumSamples = 8;
    for(uint64 x = 0; x < NumSamples; ++x)
    {
        for(uint64 y = 0; y < NumSamples; ++y)