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#ifndef _EPIPOLAR_LIGHT_SCATTERING_FUNCTIONS_FXH_
#define _EPIPOLAR_LIGHT_SCATTERING_FUNCTIONS_FXH_
void GetSunLightExtinctionAndSkyLight(in float3 f3PosWS,
in float3 f3EarthCentre,
in float3 f3LightDirection,
in AirScatteringAttribs MediaAttribs,
in Texture2D<float2> tex2DOccludedNetDensityToAtmTop,
in SamplerState tex2DOccludedNetDensityToAtmTop_sampler,
in Texture2D< float3 > tex2DAmbientSkylight,
in SamplerState tex2DAmbientSkylight_sampler,
out float3 f3Extinction,
out float3 f3AmbientSkyLight)
{
float3 f3DirFromEarthCentre = f3PosWS - f3EarthCentre;
float fDistToCentre = length(f3DirFromEarthCentre);
f3DirFromEarthCentre /= fDistToCentre;
float fAltitude = fDistToCentre - MediaAttribs.fEarthRadius;
float fCosZenithAngle = dot(f3DirFromEarthCentre, -f3LightDirection);
float fNormalizedAltitude = (fAltitude - MediaAttribs.fAtmBottomAltitude) * MediaAttribs.fAtmAltitudeRangeInv;
float2 f2ParticleDensityToAtmTop = tex2DOccludedNetDensityToAtmTop.SampleLevel( tex2DOccludedNetDensityToAtmTop_sampler, float2(fNormalizedAltitude, fCosZenithAngle*0.5 + 0.5), 0 );
float3 f3RlghOpticalDepth = MediaAttribs.f4RayleighExtinctionCoeff.rgb * f2ParticleDensityToAtmTop.x;
float3 f3MieOpticalDepth = MediaAttribs.f4MieExtinctionCoeff.rgb * f2ParticleDensityToAtmTop.y;
f3Extinction = exp( -(f3RlghOpticalDepth + f3MieOpticalDepth) );
f3AmbientSkyLight = tex2DAmbientSkylight.SampleLevel( tex2DAmbientSkylight_sampler, float2(fCosZenithAngle*0.5 + 0.5, 0.5), 0 );
}
#endif //_EPIPOLAR_LIGHT_SCATTERING_FUNCTIONS_FXH_
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