float4 _ExpFogParameters;
CBUFFER_END
#define _MipFogNear _MipFogParameters.x
#define _MipFogFar _MipFogParameters.y
#define _MipFogMaxMip _MipFogParameters.z
#define _MipFogNear _MipFogParameters.x
#define _MipFogFar _MipFogParameters.y
#define _MipFogMaxMip _MipFogParameters.z
#define _FogDensity _FogColorDensity.w
#define _FogColor _FogColorDensity
#define _FogDensity _FogColorDensity.w
#define _FogColor _FogColorDensity
#define _LinearFogStart _LinearFogParameters.x
#define _LinearFogEnd _LinearFogParameters.y
#define _LinearFogOneOverRange _LinearFogParameters.z
#define _LinearFogStart _LinearFogParameters.x
#define _LinearFogOneOverRange _LinearFogParameters.y
#define _LinearFogHeightEnd _LinearFogParameters.z
#define _LinearFogHeightOneOverRange _LinearFogParameters.w
#define _ExpFogDistance _ExpFogParameters.x
#define _ExpFogDistance _ExpFogParameters.x
#define _ExpFogBaseHeight _ExpFogParameters.y
#define _ExpFogHeightAttenuation _ExpFogParameters.z
float3 GetFogColor(PositionInputs posInput)
{
{
// Based on Uncharted 4 "Mip Sky Fog" trick: http://advances.realtimerendering.com/other/2016/naughty_dog/NaughtyDog_TechArt_Final.pdf
float mipLevel = (1.0 - _MipFogMaxMip * saturate((posInput.linearDepth - _MipFogNear) / (_MipFogFar - _MipFogNear))) * _SkyTextureMipCount;
float3 dir = normalize(posInput.positionWS - GetPrimaryCameraPosition() );
float3 dir = -GetWorldSpaceNormalizeViewDir(posInput.positionWS );
return SampleSkyTexture(dir, mipLevel).rgb;
}
else // Should not be possible.
// Returns fog color in rgb and fog factor in alpha.
float4 EvaluateAtmosphericScattering(PositionInputs posInput)
{
float3 fogColor = 0;
float fogFactor = 0;
float3 fogColor = 0;
float fogFactor = 0;
float4 volFog = SampleInScatteredRadianceAndTransmittance(TEXTURE3D_PARAM(_VBufferLighting, s_trilinear_clamp_sampler),
posInput.positionNDC, posInput.linearDepth,
_VBufferResolution, _VBufferScaleAndSliceCount,
_VBufferDepthEncodingParams);
fogColor = volFog.rgb;
fogFactor = 1 - volFog.a;
float4 volFog = SampleInScatteredRadianceAndTransmittance(TEXTURE3D_PARAM(_VBufferLighting, s_trilinear_clamp_sampler),
posInput.positionNDC, posInput.linearDepth,
_VBufferResolution, _VBufferScaleAndSliceCount,
_VBufferDepthEncodingParams);
fogColor = volFog.rgb;
fogFactor = 1 - volFog.a;
if (_AtmosphericScatteringType == FOGTYPE_EXPONENTIAL)
{
fogColor = GetFogColor(posInput);
fogFactor = _FogDensity * (1.0f - TransmittanceHomogeneousMedium(1.0f / _ExpFogDistance, posInput.linearDepth));
}
else if (_AtmosphericScatteringType == FOGTYPE_LINEAR)
{
fogColor = GetFogColor(posInput);
fogFactor = _FogDensity * saturate((posInput.linearDepth - _LinearFogStart) * _LinearFogOneOverRange);
}
else // NONE
{
}
if (_AtmosphericScatteringType == FOGTYPE_EXPONENTIAL)
{
fogColor = GetFogColor(posInput);
float3 distance = length(GetWorldSpaceViewDir(posInput.positionWS));
float fogHeight = max(0.0, GetAbsolutePositionWS(posInput.positionWS).y - _ExpFogBaseHeight);
fogFactor = _FogDensity * TransmittanceHomogeneousMedium(_ExpFogHeightAttenuation, fogHeight) * (1.0f - TransmittanceHomogeneousMedium(1.0f / _ExpFogDistance, distance));
}
else if (_AtmosphericScatteringType == FOGTYPE_LINEAR)
{
fogColor = GetFogColor(posInput);
fogFactor = _FogDensity * saturate((posInput.linearDepth - _LinearFogStart) * _LinearFogOneOverRange) * saturate((_LinearFogHeightEnd - GetAbsolutePositionWS(posInput.positionWS).y) * _LinearFogHeightOneOverRange);
}
else // NONE
{
}
return float4(fogColor, fogFactor);
return float4(fogColor, fogFactor);
}
#endif
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