Shader "Hidden/ProBuilder/NormalPreview"
{
    SubShader
    {
        Tags { "Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="Geometry" }
        Lighting Off
        ZTest LEqual
        Blend SrcAlpha OneMinusSrcAlpha
        ZWrite On
        Cull Off

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

            float _Scale;

            struct appdata
            {
                float4 vertex : POSITION;
                // secretely this is the normal, w is used to pass extrusion
                float4 tangent : TANGENT;
            };

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

            v2f vert (appdata v)
            {
                v2f o;

                float4 world = mul(unity_ObjectToWorld, v.vertex);
                float3 nrm = UnityObjectToWorldNormal(v.tangent.xyz);
                float4 extruded = world + float4((nrm * v.tangent.w * _Scale), 0);
                o.pos = mul(UNITY_MATRIX_VP, extruded);
                o.color = float4(abs(v.tangent.xyz), 1);

                return o;
            }

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

            ENDCG
        }
    }
}