outline shader

Shader "Toon/Basic Outline" {
    Properties {
        _Color ("Main Color", Color) = (.5,.5,.5,1)
        _OutlineColor ("Outline Color", Color) = (0,0,0,1)
        _Outline ("Outline width", Range (.002, 0.03)) = .005
        _OutlineAlpha ("Outline alpha", Range (0, 1)) = 1
        _MainTex ("Base (RGB)", 2D) = "white" { }
    }

    CGINCLUDE
    #include "UnityCG.cginc"

    struct appdata {
        float4 vertex : POSITION;
        float3 normal : NORMAL;
    };

    struct v2f {
        float4 pos : POSITION;
        float4 color : COLOR;
    };

    uniform float _Outline;
    uniform float _OutlineAlpha;
    uniform float4 _OutlineColor;

    v2f vert(appdata v) {
        v2f o;
        o.pos = mul(UNITY_MATRIX_MVP, v.vertex);

        float3 norm   = mul ((float3x3)UNITY_MATRIX_IT_MV, v.normal);
        norm.z = -0.4;
        float2 offset = TransformViewToProjection(norm.xy);

        o.pos.xy += offset * o.pos.z * _Outline;
        //o.pos.xy += offset * _Outline;
        //o.color = _OutlineColor;
        return o;
    }
    ENDCG

    SubShader {
        Tags { "RenderType"="Opaque" }
        UsePass "Toon/Basic/BASE"
        Pass {
            Name "OUTLINE"
            Tags { "LightMode" = "Always" }
            Cull Front
            ZWrite On
            ColorMask RGB
            Blend SrcAlpha OneMinusSrcAlpha

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            half4 frag(v2f i) :COLOR {
                half4 c = _OutlineColor;
                c.a = _OutlineAlpha;
                return c;
                //return i.color;
            }
            ENDCG
        }
    }

    SubShader {
        Tags { "RenderType"="Opaque" }
        UsePass "Toon/Basic/BASE"
        Pass {
            Name "OUTLINE"
            Tags { "LightMode" = "Always" }
            Cull Front
            ZWrite On
            ColorMask RGB
            Blend SrcAlpha OneMinusSrcAlpha

            CGPROGRAM
            #pragma vertex vert
            #pragma exclude_renderers shaderonly
            ENDCG
            SetTexture [_MainTex] { combine primary }
        }
    }

    Fallback "Toon/Basic"
}