Shader "Azure[Sky]/Vertex Sky"
{
SubShader
{
Tags { "Queue"="Background" "RenderType"="Background" "PreviewType"="Skybox" "IgnoreProjector"="True" }
Cull [_Azure_CullMode] // Render side
Fog{Mode Off} // Don't use fog
ZWrite Off // Don't draw to bepth buffer
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma target 3.0
uniform int _Azure_SunsetColorMode;
uniform float _Azure_Pi316, _Azure_Pi14, _Azure_Scattering, _Azure_SunDiskIntensity, _Azure_Pi, _Azure_Exposure, _Azure_NightIntensity, _Azure_LightSpeed, _Azure_SunSize, _Azure_MoonSize,
_Azure_MoonBrightRange, _Azure_MoonEmission, _Azure_StarfieldIntensity, _Azure_MilkyWayIntensity, _Azure_Kr, _Azure_Km;
uniform float3 _Azure_SunDirection, _Azure_MoonDirection, _Azure_Br, _Azure_Bm, _Azure_MieG, _Azure_StarfieldColorBalance;
uniform float4 _Azure_RayleighColor, _Azure_MieColor, _Azure_SunDiskColor, _Azure_MoonColor, _Azure_MoonBrightColor;
uniform float4x4 _Azure_SunMatrix, _Azure_MoonMatrix, _Azure_StarMatrix, _Azure_NoiseMatrix, _Azure_RelativeSunMatrix, _Azure_UpMatrix;
uniform sampler2D _Azure_SunTexture, _Azure_MoonTexture;
uniform samplerCUBE _Azure_StarfieldTexture, _Azure_StarNoiseTexture;
struct appdata
{
float4 vertex : POSITION;
};
struct v2f
{
float4 Position : SV_POSITION;
float3 WorldPos : TEXCOORD0;
float3 SunPos : TEXCOORD1;
float3 MoonPos : TEXCOORD2;
float3 StarPos : TEXCOORD3;
float3 NoiseRot : TEXCOORD4;
float4 OutColor : COLOR;
float4 Fex : COLOR1;
};
v2f vert (appdata v)
{
v2f Output;
UNITY_INITIALIZE_OUTPUT(v2f, Output);
Output.Position = UnityObjectToClipPos(v.vertex);
Output.WorldPos = normalize(mul((float3x3)unity_WorldToObject, v.vertex.xyz));
Output.WorldPos = normalize(mul((float3x3)_Azure_UpMatrix, Output.WorldPos));
//Matrix.
//--------------------------------
Output.SunPos = mul((float3x3)_Azure_SunMatrix, v.vertex.xyz) * 2.0 * _Azure_SunSize;
Output.StarPos = mul((float3x3)_Azure_RelativeSunMatrix, Output.WorldPos);
Output.StarPos = mul((float3x3)_Azure_StarMatrix, Output.StarPos);
Output.NoiseRot = mul((float3x3)_Azure_NoiseMatrix, v.vertex.xyz);
Output.MoonPos = mul((float3x3)_Azure_MoonMatrix, v.vertex.xyz) * 1.5 * _Azure_MoonSize;
Output.MoonPos.x *= -1.0;
//Initializations.
//--------------------------------
float3 inScatter = float3(0.0, 0.0, 0.0);
float3 nightSky = float3(0.0, 0.0, 0.0);
float3 fex = float3(0.0, 0.0, 0.0);
float r = length(float3(0.0, _Azure_LightSpeed, 0.0));
//Directions.
//--------------------------------
float3 viewDir = normalize(Output.WorldPos);
float sunCosTheta = dot(viewDir, _Azure_SunDirection);
float sunRise = saturate(dot(float3(0.0, 500.0, 0.0), _Azure_SunDirection) / r);
if(_Azure_SunsetColorMode == 0)
{
//Optical Depth.
//--------------------------------
float zenith = acos(saturate(dot(float3(0.0, 1.0, 0.0), viewDir)));
float z = cos(zenith) + 0.15 * pow(93.885 - ((zenith * 180.0) / _Azure_Pi), -1.253);
float SR = _Azure_Kr / z;
float SM = _Azure_Km / z;
//Total Extinction.
//--------------------------------
fex = exp(-(_Azure_Br*SR + _Azure_Bm*SM));
float sunset = clamp(dot(float3(0.0, 1.0, 0.0), _Azure_SunDirection), 0.0, 0.5);
float3 extinction = lerp(fex, (1.0 - fex), sunset);
//Scattering.
//--------------------------------
//float rayPhase = 1.0 + pow(sunCosTheta, 2.0); //Preetham rayleigh phase function.
float rayPhase = 2.0 + 0.5 * pow(sunCosTheta, 2.0); //Rayleigh phase function based on the Nielsen's paper.
float miePhase = _Azure_MieG.x / pow(_Azure_MieG.y - _Azure_MieG.z * sunCosTheta, 1.5); //The Henyey-Greenstein phase function.
float3 BrTheta = _Azure_Pi316 * _Azure_Br * rayPhase * _Azure_RayleighColor.rgb * extinction;
float3 BmTheta = _Azure_Pi14 * _Azure_Bm * miePhase * _Azure_MieColor.rgb * extinction * sunRise;
float3 BrmTheta = (BrTheta + BmTheta) / (_Azure_Br + _Azure_Bm);
inScatter = BrmTheta * _Azure_Scattering * (1.0 - fex);
inScatter *= sunRise;
//Night Sky.
//--------------------------------
BrTheta = _Azure_Pi316 * _Azure_Br * rayPhase * _Azure_RayleighColor.rgb;
BrmTheta = (BrTheta) / (_Azure_Br + _Azure_Bm);
nightSky = BrmTheta * _Azure_NightIntensity * (1.0 - fex);
}
else
{
//Optical Depth
//--------------------------------
float zenith = acos(length(viewDir.y));
//float zenith = acos(saturate(dot(float3(0.0, 1.0, 0.0), viewDir)));
float z = cos(zenith) + 0.15 * pow(93.885 - ((zenith * 180.0) / _Azure_Pi), -1.253);
float SR = _Azure_Kr / z;
float SM = _Azure_Km / z;
//Total Extinction.
//--------------------------------
fex = exp(-(_Azure_Br*SR + _Azure_Bm*SM));
//Scattering.
//--------------------------------
float rayPhase = 2.0 + 0.5 * pow(sunCosTheta, 2.0);
float miePhase = _Azure_MieG.x / pow(_Azure_MieG.y - _Azure_MieG.z * sunCosTheta, 1.5);
float3 BrTheta = _Azure_Pi316 * _Azure_Br * rayPhase * _Azure_RayleighColor.rgb;
float3 BmTheta = _Azure_Pi14 * _Azure_Bm * miePhase * _Azure_MieColor.rgb * sunRise;
float3 BrmTheta = (BrTheta + BmTheta) / (_Azure_Br + _Azure_Bm);
inScatter = BrmTheta * _Azure_Scattering * (1.0 - fex);
inScatter *= sunRise;
//inScatter *= pow(max(0.5, viewDir.y + 0.5), 2.0);
//Night Sky.
//--------------------------------
//nightSky = (1.0 - fex) * _Azure_RayleighColor.rgb * _Azure_NightIntensity;
BrmTheta = (BrTheta) / (_Azure_Br + _Azure_Bm);
nightSky = BrmTheta * _Azure_NightIntensity * (1.0 - fex);
}
float horizonExtinction = saturate((viewDir.y) * 1000.0) * fex.b;
//Moon Bright.
//--------------------------------
float moonRise = saturate(dot(float3(0.0, 500.0, 0.0), _Azure_MoonDirection) / r);
float bright = 1.0 + dot(viewDir, -_Azure_MoonDirection);
float3 moonBright = 1.0 / (1.0 + bright * _Azure_MoonBrightRange) * _Azure_MoonBrightColor.rgb;
moonBright += 1.0 / (_Azure_MoonEmission + bright * 200.0) * _Azure_MoonColor.rgb;
moonBright = moonBright * moonRise;
float4 OutputColor = float4(inScatter + nightSky + moonBright, horizonExtinction);
//Outputs.
//--------------------------------
Output.OutColor = OutputColor;
Output.Fex = float4(fex, sunCosTheta);
return Output;
}
bool iSphere(in float3 origin, in float3 direction, in float3 position, in float radius, out float3 normalDirection)
{
float3 rc = origin - position;
float c = dot(rc, rc) - (radius * radius);
float b = dot(direction, rc);
float d = b * b - c;
float t = -b - sqrt(abs(d));
float st = step(0.0, min(t, d));
normalDirection = normalize(-position + (origin + direction * t));
if (st > 0.0) { return true; }
return false;
}
float4 frag (v2f IN) : SV_Target
{
//Sun Disk.
//--------------------------------
float3 sunTex = tex2D( _Azure_SunTexture, IN.SunPos + 0.5).rgb * _Azure_SunDiskColor * _Azure_SunDiskIntensity;
sunTex = pow(sunTex, 2.0);
sunTex *= IN.Fex.b * saturate(IN.Fex.a);
//Moon Sphere.
//--------------------------------
float3 rayOrigin = float3(0.0, 0.0, 0.0);//_WorldSpaceCameraPos;
float3 rayDirection = normalize(IN.WorldPos);
float moonCosTheta = saturate(dot(rayDirection, _Azure_MoonDirection));
float3 moonPosition = _Azure_MoonDirection * 38400.0 * _Azure_MoonSize;
float3 normalDirection = float3(0.0, 0.0, 0.0);
float3 moonColor = float3(0.0, 0.0, 0.0);
float4 moonTex = tex2D( _Azure_MoonTexture, IN.MoonPos.xy + 0.5) * moonCosTheta;
float moonMask = 1.0 - moonTex.a;
if(iSphere(rayOrigin, rayDirection, moonPosition, 17370.0, normalDirection))
{
float moonSphere = max(dot(normalDirection, _Azure_SunDirection), 0.0) * moonTex.a * 2.0;
moonColor = moonTex.rgb * moonSphere * _Azure_MoonColor.rgb * IN.OutColor.a;
}
//Starfield.
//--------------------------------
float scintillation = texCUBE(_Azure_StarNoiseTexture, IN.NoiseRot) * 2.0;
float4 starTex = texCUBE(_Azure_StarfieldTexture, IN.StarPos);
float3 stars = starTex.rgb * starTex.a * scintillation;
float3 milkyWay = pow(starTex.rgb, 1.5) * _Azure_MilkyWayIntensity;
float3 starfield = (stars + milkyWay) * _Azure_StarfieldColorBalance * moonMask * IN.OutColor.a * _Azure_StarfieldIntensity;
//Output.
//--------------------------------
float3 OutputColor = IN.OutColor.rgb + sunTex + starfield + moonColor;
//Tonemapping.
OutputColor = saturate(1.0 - exp(-_Azure_Exposure * OutputColor));
//Color Correction.
OutputColor = pow(OutputColor, 2.2);
#ifdef UNITY_COLORSPACE_GAMMA
OutputColor = pow(OutputColor, 0.4545);
#else
OutputColor = OutputColor;
#endif
return float4(OutputColor, 1.0);
}
ENDCG
}
}
}