MapReveal

Shader "Custom/MapReveal" {

	Properties{
		_MainTex("Explored Texture", 2D) = "white" {}
		_PaintMap("RevealMap", 2D) = "white" {} // texture to paint on
	}
		SubShader{
		Tags{ "RenderType" = "Opaque" "LightMode" = "ForwardBase" }

		Pass{
		Lighting Off

		CGPROGRAM

#pragma vertex vert
#pragma fragment frag


#include "UnityCG.cginc"
#include "AutoLight.cginc"

	struct v2f {
		float4 pos : SV_POSITION;
		float2 uv0 : TEXCOORD0;
		float2 uv1 : TEXCOORD1;

	};

	struct appdata {
		float4 vertex : POSITION;
		float2 texcoord : TEXCOORD0;
		float2 texcoord1 : TEXCOORD1;

	};

	sampler2D _PaintMap;
	sampler2D _MainTex;
	float4 _MainTex_ST;
	v2f vert(appdata v) {
		v2f o;
		o.pos = UnityObjectToClipPos(v.vertex);
		o.uv0 = TRANSFORM_TEX(v.texcoord, _MainTex);
		o.uv1 = v.texcoord1.xy * unity_LightmapST.xy + unity_LightmapST.zw;// lightmap uvs
		return o;
	}

	half4 frag(v2f o) : COLOR{
		half4 main_color = tex2D(_MainTex, o.uv0); // main texture
		half4 paint = (tex2D(_PaintMap, o.uv1)); // painted on texture
		float4 endresult = (1-paint.r) * main_color; // reveal main texture where painted black
		return endresult;
	}
		ENDCG
	}
	}