您最多选择25个主题
主题必须以中文或者字母或数字开头，可以包含连字符 (-)，并且长度不得超过35个字符
107 行
3.7 KiB
107 行
3.7 KiB
#ifndef UNITY_ATMOSPHERIC_SCATTERING_INCLUDED
|
|
#define UNITY_ATMOSPHERIC_SCATTERING_INCLUDED
|
|
|
|
#include "CoreRP/ShaderLibrary/VolumeRendering.hlsl"
|
|
#include "CoreRP/ShaderLibrary/Filtering.hlsl"
|
|
|
|
#include "AtmosphericScattering.cs.hlsl"
|
|
#include "../SkyVariables.hlsl"
|
|
#include "../../ShaderVariables.hlsl"
|
|
#include "../../Lighting/Volumetrics/VBuffer.hlsl"
|
|
|
|
#if (SHADEROPTIONS_VOLUMETRIC_LIGHTING_PRESET != 0)
|
|
TEXTURE3D(_VBufferLighting);
|
|
#endif
|
|
|
|
CBUFFER_START(AtmosphericScattering)
|
|
int _AtmosphericScatteringType;
|
|
// Common
|
|
float _FogColorMode;
|
|
float4 _FogColorDensity; // color in rgb, density in alpha
|
|
float4 _MipFogParameters;
|
|
// Linear fog
|
|
float4 _LinearFogParameters;
|
|
// Exp fog
|
|
float4 _ExpFogParameters;
|
|
CBUFFER_END
|
|
|
|
#define _MipFogNear _MipFogParameters.x
|
|
#define _MipFogFar _MipFogParameters.y
|
|
#define _MipFogMaxMip _MipFogParameters.z
|
|
|
|
#define _FogDensity _FogColorDensity.w
|
|
#define _FogColor _FogColorDensity
|
|
|
|
#define _LinearFogStart _LinearFogParameters.x
|
|
#define _LinearFogOneOverRange _LinearFogParameters.y
|
|
#define _LinearFogHeightEnd _LinearFogParameters.z
|
|
#define _LinearFogHeightOneOverRange _LinearFogParameters.w
|
|
|
|
#define _ExpFogDistance _ExpFogParameters.x
|
|
#define _ExpFogBaseHeight _ExpFogParameters.y
|
|
#define _ExpFogHeightAttenuation _ExpFogParameters.z
|
|
|
|
float3 GetFogColor(PositionInputs posInput)
|
|
{
|
|
if (_FogColorMode == FOGCOLORMODE_CONSTANT_COLOR)
|
|
{
|
|
return _FogColor.rgb;
|
|
}
|
|
else if (_FogColorMode == FOGCOLORMODE_SKY_COLOR)
|
|
{
|
|
// 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 = -GetWorldSpaceNormalizeViewDir(posInput.positionWS);
|
|
return SampleSkyTexture(dir, mipLevel).rgb;
|
|
}
|
|
else // Should not be possible.
|
|
return float3(0.0, 0.0, 0.0);
|
|
}
|
|
|
|
// Returns fog color in rgb and fog factor in alpha.
|
|
float4 EvaluateAtmosphericScattering(PositionInputs posInput)
|
|
{
|
|
float3 fogColor = 0;
|
|
float fogFactor = 0;
|
|
|
|
switch (_AtmosphericScatteringType)
|
|
{
|
|
case FOGTYPE_LINEAR:
|
|
{
|
|
fogColor = GetFogColor(posInput);
|
|
fogFactor = _FogDensity * saturate((posInput.linearDepth - _LinearFogStart) * _LinearFogOneOverRange) * saturate((_LinearFogHeightEnd - GetAbsolutePositionWS(posInput.positionWS).y) * _LinearFogHeightOneOverRange);
|
|
break;
|
|
}
|
|
case FOGTYPE_EXPONENTIAL:
|
|
{
|
|
fogColor = GetFogColor(posInput);
|
|
float 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));
|
|
break;
|
|
}
|
|
case FOGTYPE_VOLUMETRIC:
|
|
{
|
|
#if (SHADEROPTIONS_VOLUMETRIC_LIGHTING_PRESET != 0)
|
|
float4 volFog = SampleVolumetricLighting(TEXTURE3D_PARAM(_VBufferLighting, s_linear_clamp_sampler),
|
|
posInput.positionNDC,
|
|
posInput.linearDepth,
|
|
_VBufferResolution,
|
|
_VBufferSliceCount.xy,
|
|
_VBufferUvScaleAndLimit.xy,
|
|
_VBufferUvScaleAndLimit.zw,
|
|
_VBufferDepthEncodingParams,
|
|
_VBufferDepthDecodingParams,
|
|
true, true);
|
|
|
|
fogFactor = 1 - volFog.a; // Opacity from transmittance
|
|
fogColor = volFog.rgb * min(rcp(fogFactor), FLT_MAX); // Un-premultiply, clamp to avoid (0 * INF = NaN)
|
|
#endif
|
|
break;
|
|
}
|
|
}
|
|
|
|
return float4(fogColor, fogFactor);
|
|
}
|
|
|
|
#endif
|