Shader "Outlined/Silhouette Only"
{
    Properties{
        _OutlineColor("Outline Color", Color) = (0,0,0,1)
        _Outline("Outline width", Range(0.0, 1.0)) = .005
    }

        CGINCLUDE
#include "UnityCG.cginc"

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

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

    uniform float _Outline;
    uniform float4 _OutlineColor;

    v2f vert(appdata v) {
        // just make a copy of incoming vertex data but scaled according to normal direction
        v2f o;
        o.pos = UnityObjectToClipPos(v.vertex);

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

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

        SubShader{
            Tags { "Queue" = "Transparent" }

            Pass {
                Name "BASE"
                Cull Back
                Blend Zero One

        // uncomment this to hide inner details:
        //Offset -8, -8

        SetTexture[_OutlineColor] {
            ConstantColor(0,0,0,0)
            Combine constant
        }
    }

        // note that a vertex shader is specified here but it's using the one above
        Pass {
            Name "OUTLINE"
            Tags { "LightMode" = "Always" }
            Cull Front

        // you can choose what kind of blending mode you want for the outline
        //Blend SrcAlpha OneMinusSrcAlpha // Normal
        //Blend One One // Additive
        Blend One OneMinusDstColor // Soft Additive
        //Blend DstColor Zero // Multiplicative
        //Blend DstColor SrcColor // 2x Multiplicative

CGPROGRAM
#pragma vertex vert
#pragma fragment frag

half4 frag(v2f i) :COLOR {
    return i.color;
}
ENDCG
        }


    }

        Fallback "Diffuse"
}