InvertedFog

Shader "xdegtyarev/InvertedFog"
{
	Properties
	{
		_FogTexture ("Alpha8", 2D) = "white" {}
		_FogIntencity("Intencity", Float) = 0.5
	}

	SubShader
	{
		Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
		ZWrite Off
		Lighting Off
		Cull Off
		Fog { Mode Off }
		Blend SrcAlpha OneMinusSrcAlpha

		Pass
		{
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma fragmentoption ARB_precision_hint_fastest
			#include "UnityCG.cginc"

			sampler2D _FogTexture;
			float4 _FogTexture_ST;
			float _FogIntencity;

			struct vertDataIn
			{
				float4 vertex : POSITION;
				float2 texcoord : TEXCOORD0;
			};

			struct vertDataOut
			{
				float4 vertex : POSITION;
				float2 texcoord : TEXCOORD0;
			};

			vertDataOut vert(vertDataIn v)
			{
				vertDataOut o;
				o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
				o.texcoord = TRANSFORM_TEX(v.texcoord,_FogTexture);
				return o;
			}

			fixed4 frag(vertDataOut i) : COLOR
			{
				fixed4 col = half4(0,0,0,1) * (1 - tex2D(_FogTexture, i.texcoord).a) * _FogIntencity;
				return col;
			}

			ENDCG
		}
	}
}