Shader "DBV/Kristo/WallClip"
{
    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

        _Color ("Main color", Color) = (1,1,1,1)
        _FadeDistance ("Fade distance", Float) = 10
        _FadeSmooth ("Fade smooth distance", Float) = 1

        _DitherTex ("Texture", 2D) = "grey" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 200

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        #pragma surface surf Standard fullforwardshadows

        // Use shader model 3.0 target, to get nicer looking lighting
        #pragma target 3.0

        half _Glossiness;
        half _Metallic;

        sampler2D _MainTex, _DitherTex;
        float4 _DitherTex_TexelSize;

        float4 _Color;
        float _FadeDistance, _FadeSmooth;

        struct Input
        {
            float2 uv_MainTex;
            float4 screenPos;
            float3 worldPos;
        };

        // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
        // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
        // #pragma instancing_options assumeuniformscaling
        UNITY_INSTANCING_BUFFER_START(Props)
            // put more per-instance properties here
        UNITY_INSTANCING_BUFFER_END(Props)

        void surf (Input IN, inout SurfaceOutputStandard o) {
            // Albedo comes from a texture tinted by color
            fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = c.rgb;
            // Metallic and smoothness come from slider variables
            o.Metallic = _Metallic;
            o.Smoothness = _Glossiness;
            o.Alpha = c.a;

            // sample the texture
            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;

            float2 screenPos = IN.screenPos.xy / IN.screenPos.w;
                float2 ditherCoordinate = screenPos * _ScreenParams.xy * _DitherTex_TexelSize.xy;
                float ditherValue = tex2D(_DitherTex, ditherCoordinate).r;

            if(dis < fadeDis) {
                clip(-1);
                }
            else if (dis < fadeSmooth) {
                float v = (1-(fadeSmooth-dis)/fade);
                float d = v * c.a - ditherValue;
                clip(d);
                c.a = d;
                }
            else {
                float d = c.a - ditherValue;
                clip(d);
                c.a = d;
                }
            //o.Alpha = c.a;
            }
        ENDCG
    }
    FallBack "Diffuse"
}