cvr-props/Assets/sunset_box/sunset_dynamic.shader

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Shader "CrispyPin/Sunset (Dynamic)"
{
Properties
{
[Header(Sky)]
_SkyCol ("Sky color", Color) = (0.22, 0.23, 0.58, 1.0)
_HorizonCol ("Horizon color", Color) = (0.43, 0.27, 0.49, 1.0)
[Header(Sun)]
_SunCol ("Sun color", Color) = (1.0, 0.65, 0.05, 1.0)
_SunAngle ("Sun angle", Range(0, 6.28)) = 0
_SunRadius ("Sun radius", Range(0, 0.3)) = 0.06
_SunCutoff ("Sun cutoff", Range(0, 0.5)) = 0.08
[Header(Star Layout)]
[NoScaleOffset]
_MainTex ("Noise source", 2D) = "white" {}
_StarDensity ("Star density", Range(4, 50)) = 20
_StarRandom ("Star randomness", Range(0, 1)) = 0.85
[Header(Star)]
_StarsMissing ("Stars missing", Range(0, 1)) = 0.75
_StarSize ("Star size", Range(0, 0.1)) = 0.06
_StarSizeRandom ("Star size randomness", Range(0, 1)) = 0.5
_StarTint ("Star tint", Range(0, 1)) = 0.4
[Header(Debug)]
_Grid ("Grid visibility", Range(0, 1)) = 0
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100
Cull back
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#define PI 3.1416f
#define WHITE fixed4(1.0, 1.0, 1.0, 1.0)
struct appdata
{
float4 vertex : POSITION;
};
struct v2f
{
float4 vertex : SV_POSITION;
float3 camPos : TEXCOORD1;
float3 hitPos : TEXCOORD2;
};
sampler2D _MainTex;
fixed4 _SkyCol;
fixed4 _HorizonCol;
float _StarsMissing;
float _StarDensity;
float _StarRandom;
float _StarSize;
float _StarSizeRandom;
float _StarTint;
fixed4 _SunCol;
float _SunAngle;
float _SunRadius;
float _SunCutoff;
float _Grid;
v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.camPos = _WorldSpaceCameraPos;
o.hitPos = mul(unity_ObjectToWorld, v.vertex);
return o;
}
fixed4 frag (v2f i) : SV_Target
{
float3 dir = normalize(i.hitPos - i.camPos);
float y = asin(dir.y);
float phi = atan2(dir.x, dir.z);
/// sky
float factor = smoothstep(0.0, 0.5, dir.y + 0.2);
factor = min(factor, 1.0);
fixed4 col = lerp(_HorizonCol, _SkyCol, factor);
/// stars
float2 cells = float2(-1, floor(_StarDensity));
float cell_x_base = floor(cells.y * PI);
float celly = y * cells.y;
// cells per ring depend on y pos, to reduce warping around the poles:
cells.x = max(floor(cos(floor(celly)/_StarDensity) * cell_x_base), 3);
float cellx = (phi / PI * cells.x);
float2 pos = float2(cellx, celly);// cell-space pos of this fragment
float2 cell_pos = float2(floor(cellx), floor(celly)); // position of this cell
float2 cell_center = cell_pos + float2(0.5, 0.5);
float2 star_pos = cell_center + (tex2D(_MainTex, cell_pos / cells + float2(0., 0.1)) - 0.5) * _StarRandom;
/// star color
float3 r = tex2D(_MainTex, cell_pos / cells);
float rnum = frac((r.r + r.g - r.b) * 10);
float rnum2 = frac((r.r - r.g + r.b) * 10);
float star_size = _StarSize * (rnum * _StarSizeRandom + (1 - _StarSizeRandom));
float distance = length(pos - star_pos);
float star_strength = max(min(star_size/distance*0.5, 1.25)-0.25, 0); // star glow
star_strength *= clamp(sin(y*2) - 0.1, 0, 1); // fade stars near/under horizon
star_strength *= length(r)/2; // fade stars
star_strength *= rnum2 > _StarsMissing; // remove stars
fixed3 star_col = lerp(1.0, r, _StarTint);
col = lerp(col, fixed4(star_col, 1.0), star_strength);
/// debug grid
col = lerp(col, WHITE, _Grid * (frac(cellx) < 0.04 || frac(celly) < 0.04) );
/// sun
float3 sun_dir = float3(sin(_SunAngle), 0.0, cos(_SunAngle));
float alignment = min(acos(dot(dir, sun_dir)), 1);
// float sun_gradient = pow(y-1, 2) * 0.5 + 0.8;
float sun_gradient = 1;
float sun_amount = max(min(_SunRadius/alignment * sun_gradient, 5) - _SunCutoff, 0);
col = lerp(col, _SunCol, sun_amount);
return col;
}
ENDCG
}
}
}