Shader "Custom/ClipShaderV2"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Albedo (RGB)", 2D) = "white" {}
        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Metallic ("Metallic", Range(0,1)) = 0.0

        _BackFaceColor ("Inside color", Color) = (1,1,1,1)
        _FadeColor ("Rim color", Color) = (1,1,1,1)
        _FadeDistance ("Fade distance", Float) = 10
        _FadeSmooth ("Fade smooth distance", Float) = 1
    }
    SubShader
    {
        Tags { "RenderType"="Opaque"}
        Cull Off
        LOD 200

        CGPROGRAM
        #pragma surface surf Standard noshadow
        #pragma target 3.0

        #include "UnityCG.cginc"

        sampler2D _MainTex;
        float4 _FadeColor, _BackFaceColor;
        float _FadeDistance, _FadeSmooth;

        struct Input {
            float3 worldPos;
            float2 uv_MainTex;
            float facing : VFACE;//-1 = if backface
            };

        half _Glossiness;
        half _Metallic;
        fixed4 _Color;

        void surf (Input IN, inout SurfaceOutputStandard o) {
            //color
            fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = c.rgb;
            // Other unity stuff
            o.Metallic = _Metallic;
            o.Smoothness = _Glossiness;
            o.Alpha = c.a;

            if(IN.facing == -1) {//backface
                o.Albedo = _BackFaceColor;
                }
            
            //Camera sphere clip
            fixed3 vec = IN.worldPos.xyz - _WorldSpaceCameraPos;
            float dis = vec.x*vec.x + vec.y*vec.y + vec.z*vec.z;

            float fadeDis = _FadeDistance * _FadeDistance;
            float fade = _FadeSmooth * _FadeSmooth;
            float fadeSmooth = fadeDis + fade;

            if(dis < fadeDis) {
                clip(-1);
                }
            else if (dis < fadeSmooth && IN.facing == 1) {
                float v = (1-(fadeSmooth-dis)/fade);
                o.Albedo = o.Albedo * v + (1-v) * _FadeColor;
                }

            
            }
        ENDCG
    }
    FallBack "Diffuse"
}