gistfile1.txt

Shader "Custom/Frost" {
  Properties {
		_MainTex ("Frost Map (RGB)", 2D) = "white" {}
		_FrostColor ("Frost Color", Color) = (1.0, 1.0, 1.0, 1.0)
		_Mask ("Mask", Vector) = (1.0, 1.0, 1.0, 1.0)
	}
	SubShader {
		Tags { "Queue"="Transparent" "RenderType"="Transparent" }
		LOD 100
		Pass {
			Blend SrcAlpha OneMinusSrcAlpha
			ZWrite Off
			Lighting Off
			
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			
			uniform sampler2D _MainTex;
			uniform float4 _Mask;
			uniform fixed4 _FrostColor;
			
			struct Attribute {
				float4 vertex : POSITION;
				half2 texcoord : TEXCOORD0;
			};
			
			struct Varying {
				float4 pos : SV_POSITION;
				half2 uv : TEXCOORD1;
			};
			
			Varying vert(Attribute a) {
				Varying v;
				v.pos = mul(UNITY_MATRIX_MVP, a.vertex);
				v.uv = a.texcoord;
				return v;
			}
			
			fixed4 frag(Varying v) : COLOR {
				fixed4 c = tex2D(_MainTex, v.uv);
				float r = step(0.1f, _Mask.x*c.r)*c.r*2.0f;
				float b = step(0.1f, _Mask.y*c.b)*.5f;
				fixed4 res = _FrostColor;
				res.a = max(max(r, _Mask.z*c.g), b);
				return res;
			} 
			
			ENDCG
		}
	} 
}