Shader "Hidden/Post FX/Fog"
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{
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Properties
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{
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_MainTex("Main Texture", 2D) = "white" {}
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}
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CGINCLUDE
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#pragma multi_compile __ FOG_LINEAR FOG_EXP FOG_EXP2
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#include "UnityCG.cginc"
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#include "Common.cginc"
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#define SKYBOX_THREASHOLD_VALUE 0.9999
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struct Varyings
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{
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float2 uv : TEXCOORD0;
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float4 vertex : SV_POSITION;
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};
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Varyings VertFog(AttributesDefault v)
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{
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Varyings o;
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o.vertex = UnityObjectToClipPos(v.vertex);
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o.uv = UnityStereoScreenSpaceUVAdjust(v.texcoord, _MainTex_ST);
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return o;
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}
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sampler2D _CameraDepthTexture;
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half4 _FogColor;
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float _Density;
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float _Start;
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float _End;
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half ComputeFog(float z)
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{
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half fog = 0.0;
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#if FOG_LINEAR
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fog = (_End - z) / (_End - _Start);
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#elif FOG_EXP
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fog = exp2(-_Density * z);
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#else // FOG_EXP2
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fog = _Density * z;
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fog = exp2(-fog * fog);
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#endif
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return saturate(fog);
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}
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float ComputeDistance(float depth)
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{
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float dist = depth * _ProjectionParams.z;
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dist -= _ProjectionParams.y;
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return dist;
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}
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half4 FragFog(Varyings i) : SV_Target
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{
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half4 color = tex2D(_MainTex, i.uv);
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float depth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv);
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depth = Linear01Depth(depth);
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float dist = ComputeDistance(depth);
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half fog = 1.0 - ComputeFog(dist);
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return lerp(color, _FogColor, fog);
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}
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half4 FragFogExcludeSkybox(Varyings i) : SV_Target
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{
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half4 color = tex2D(_MainTex, i.uv);
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float depth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv);
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depth = Linear01Depth(depth);
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float skybox = depth < SKYBOX_THREASHOLD_VALUE;
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float dist = ComputeDistance(depth);
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half fog = 1.0 - ComputeFog(dist);
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return lerp(color, _FogColor, fog * skybox);
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}
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ENDCG
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SubShader
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{
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Cull Off ZWrite Off ZTest Always
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Pass
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{
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CGPROGRAM
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#pragma vertex VertFog
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#pragma fragment FragFog
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ENDCG
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}
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Pass
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{
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CGPROGRAM
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#pragma vertex VertFog
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#pragma fragment FragFogExcludeSkybox
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ENDCG
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}
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}
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}
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