Shader "Hidden/ProBuilder/SmoothingPreview"
{
    Properties {
        _Opacity ("Opacity", Float) = .5
    }

    SubShader
    {
        Tags { "IgnoreProjector"="True" "RenderType"="Geometry" }
        Lighting Off
        ZTest LEqual
        ZWrite On
        Cull Back
        Blend SrcAlpha OneMinusSrcAlpha

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            float _Opacity;
            float _Dither;

            struct appdata
            {
                float4 vertex : POSITION;
                float4 color : COLOR;
            };

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

            v2f vert (appdata v)
            {
                v2f o;

                o.pos = float4(UnityObjectToViewPos(v.vertex.xyz), 1);
                o.pos.xyz *= .98;
                o.pos = mul(UNITY_MATRIX_P, o.pos);
                o.color = v.color;

                return o;
            }

            half4 frag (v2f i) : COLOR
            {
                i.pos.xy = floor(i.pos.xy * 1) * .5;
                float checker = -frac(i.pos.x + i.pos.y);
                clip(lerp(1, checker, _Dither));

                half4 c = half4(i.color.rgb, i.color.a * _Opacity);
                return c;
            }

            ENDCG
        }
    }
}