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
 
 
 
 

73 行
2.4 KiB

#ifndef UNITY_ATMOSPHERIC_SCATTERING_INCLUDED
#define UNITY_ATMOSPHERIC_SCATTERING_INCLUDED
#include "../../../Core/ShaderLibrary/VolumeRendering.hlsl"
#include "AtmosphericScattering.cs.hlsl"
#include "../SkyVariables.hlsl"
#include "../../ShaderVariables.hlsl"
CBUFFER_START(AtmosphericScattering)
float _AtmosphericScatteringType;
// Common
float _FogColorMode;
float4 _FogColor;
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 _LinearFogStart _LinearFogParameters.x
#define _LinearFogEnd _LinearFogParameters.y
#define _LinearFogOneOverRange _LinearFogParameters.z
#define _LinearFogDensity _LinearFogParameters.w
#define _ExpFogDistance _ExpFogParameters.x
#define _ExpFogDensity _ExpFogParameters.y
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.depthVS - _MipFogNear) / (_MipFogFar - _MipFogNear))) * _SkyTextureMipCount;
float3 dir = normalize(posInput.positionWS - GetPrimaryCameraPosition());
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)
{
if (_AtmosphericScatteringType == FOGTYPE_EXPONENTIAL)
{
float3 fogColor = GetFogColor(posInput);
float fogFactor = _ExpFogDensity * (1.0f - Transmittance(OpticalDepthHomogeneous(1.0f / _ExpFogDistance, posInput.depthVS)));
return float4(fogColor, fogFactor);
}
else if (_AtmosphericScatteringType == FOGTYPE_LINEAR)
{
float3 fogColor = GetFogColor(posInput);
float fogFactor = _LinearFogDensity * saturate((posInput.depthVS - _LinearFogStart) * _LinearFogOneOverRange);
return float4(fogColor, fogFactor);
}
else // NONE
{
return float4(0.0, 0.0, 0.0, 0.0);
}
}
#endif