SkyEmitter(Stream *stream, InstanceManager *manager)
: Emitter(stream, manager) {
m_scale = stream->readFloat();
m_turbidity = stream->readFloat();
m_stretch = stream->readFloat();
m_resolution = stream->readInt();
m_extend = stream->readBool();
m_albedo = Spectrum(stream);
m_sun = SphericalCoordinates(stream);
Float sunElevation = 0.5f * M_PI - m_sun.elevation;
#if SPECTRUM_SAMPLES == 3
for (int i=0; i<SPECTRUM_SAMPLES; ++i)
m_state[i] = arhosek_rgb_skymodelstate_alloc_init(
m_turbidity, m_albedo[i], sunElevation);
#else
for (int i=0; i<SPECTRUM_SAMPLES; ++i)
m_state[i] = arhosekskymodelstate_alloc_init(
m_turbidity, m_albedo[i], sunElevation);
#endif
configure();
}
SkyEmitter(const Properties &props)
: Emitter(props) {
m_scale = props.getFloat("scale", 1.0f);
m_turbidity = props.getFloat("turbidity", 3.0f);
m_stretch = props.getFloat("stretch", 1.0f);
m_resolution = props.getInteger("resolution", 512);
m_albedo = props.getSpectrum("albedo", Spectrum(0.2f));
m_sun = computeSunCoordinates(props);
m_extend = props.getBoolean("extend", false);
if (m_turbidity < 1 || m_turbidity > 10)
Log(EError, "The turbidity parameter must be in the range [1,10]!");
if (m_stretch < 1 || m_stretch > 2)
Log(EError, "The stretch parameter must be in the range [1,2]!");
for (int i=0; i<SPECTRUM_SAMPLES; ++i) {
if (m_albedo[i] < 0 || m_albedo[i] > 1)
Log(EError, "The albedo parameter must be in the range [0,1]!");
}
Float sunElevation = 0.5f * M_PI - m_sun.elevation;
if (sunElevation < 0)
Log(EError, "The sun is below the horizon -- this is not supported by the sky model.");
#if SPECTRUM_SAMPLES == 3
for (int i=0; i<SPECTRUM_SAMPLES; ++i)
m_state[i] = arhosek_rgb_skymodelstate_alloc_init(
m_turbidity, m_albedo[i], sunElevation);
#else
for (int i=0; i<SPECTRUM_SAMPLES; ++i)
m_state[i] = arhosekskymodelstate_alloc_init(
m_turbidity, m_albedo[i], sunElevation);
#endif
configure();
}
TextureResult HosekWilkieSky(const BufferUploads::TextureDesc& desc, const ParameterBox& parameters)
{
// The "turbidity" parameter is Linke’s turbidity factor. Hosek and Wilkie give these example parameters:
// T = 2 yields a very clear, Arctic-like sky
// T = 3 a clear sky in a temperate climate
// T = 6 a sky on a warm, moist day
// T = 10 a slightly hazy day
// T > 50 represent dense fog
auto defaultSunDirection = Normalize(Float3(1.f, 1.f, 0.33f));
Float3 sunDirection = parameters.GetParameter<Float3>(ParameterBox::ParameterNameHash("SunDirection"), defaultSunDirection);
sunDirection = Normalize(sunDirection);
auto turbidity = (double)parameters.GetParameter(ParameterBox::ParameterNameHash("turbidity"), 3.f);
auto albedo = (double)parameters.GetParameter(ParameterBox::ParameterNameHash("albedo"), 0.1f);
auto elevation = (double)Deg2Rad(parameters.GetParameter(ParameterBox::ParameterNameHash("elevation"), XlASin(sunDirection[2])));
auto* state = arhosek_rgb_skymodelstate_alloc_init(turbidity, albedo, elevation);
auto pixels = std::make_unique<Float4[]>(desc._width*desc._height);
for (unsigned y=0; y<desc._height; ++y)
for (unsigned x=0; x<desc._width; ++x) {
auto p = y*desc._width+x;
pixels[p] = Float4(0.f, 0.f, 0.f, 1.f);
Float3 direction(0.f, 0.f, 0.f);
bool hitPanel = false;
for (unsigned c = 0; c < 6; ++c) {
Float2 tc(x / float(desc._width), y / float(desc._height));
auto tcMins = s_verticalPanelCoords[c][0];
auto tcMaxs = s_verticalPanelCoords[c][1];
if (tc[0] >= tcMins[0] && tc[1] >= tcMins[1] && tc[0] < tcMaxs[0] && tc[1] < tcMaxs[1]) {
tc[0] = 2.0f * (tc[0] - tcMins[0]) / (tcMaxs[0] - tcMins[0]) - 1.0f;
tc[1] = 2.0f * (tc[1] - tcMins[1]) / (tcMaxs[1] - tcMins[1]) - 1.0f;
hitPanel = true;
auto plusX = s_verticalPanels[c][0];
auto plusY = s_verticalPanels[c][1];
auto center = s_verticalPanels[c][2];
direction = center + plusX * tc[0] + plusY * tc[1];
}
}
if (hitPanel) {
auto theta = CartesianToSpherical(direction)[0];
theta = std::min(.4998f * gPI, theta);
auto gamma = XlACos(std::max(0.f, Dot(Normalize(direction), sunDirection)));
auto R = arhosek_tristim_skymodel_radiance(state, theta, gamma, 0);
auto G = arhosek_tristim_skymodel_radiance(state, theta, gamma, 1);
auto B = arhosek_tristim_skymodel_radiance(state, theta, gamma, 2);
pixels[p][0] = (float)R;
pixels[p][1] = (float)G;
pixels[p][2] = (float)B;
}
}
arhosekskymodelstate_free(state);
return TextureResult
{
BufferUploads::CreateBasicPacket(
(desc._width*desc._height)*sizeof(Float4),
pixels.get(),
BufferUploads::TexturePitches(desc._width*sizeof(Float4), desc._width*desc._height*sizeof(Float4))),
RenderCore::Metal::NativeFormat::R32G32B32A32_FLOAT,
UInt2(desc._width, desc._height)
};
}
