Shader "Carmen/SDF/Light Strip"
{
    Properties
    {
        _MainTex ("_MainTex", 2D) = "white" {}
        _Color ("Color", Color) = (1,1,1,1)
        _Glow ("Glow", Range(0.0, 100.0)) = 0.0
    }
    SubShader
    {
        Tags { "Queue"="Transparent" "RenderType"="Transparent" }
        LOD 200

        Pass {
            Cull Off
            Blend SrcAlpha OneMinusSrcAlpha

            CGPROGRAM
            #include "UnityCG.cginc"
            #pragma vertex vert
            #pragma fragment frag
            
            UNITY_DECLARE_TEX2D(_MainTex);
            float4 _MainTex_ST;
            fixed4 _Color;
            half _Glow;

            struct Data
            {
                float4 vertex : POSITION;
                float4 normal : NORMAL;
                float2 uv : TEXCOORD0;
            };

            struct V2F
            {
                float4 position : SV_POSITION;
                float2 uv : TEXCOORD0;
            };

            V2F vert(Data v)
            {
                V2F o;
                o.position = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            fixed4 frag(V2F i) : SV_TARGET
            {
                half _LineThickness = 0.05;

				half sdf_sample = UNITY_SAMPLE_TEX2D(_MainTex, i.uv).r;
				half sdf_halfchange = (abs(ddx(sdf_sample)) + abs(ddy(sdf_sample))) / 2.0;
				half alphastep_loweredge = (1.0 - _LineThickness) - sdf_halfchange;
				half alphastep_upperedge = (1.0 - _LineThickness) + sdf_halfchange;
				half alphastep = saturate((sdf_sample - alphastep_loweredge) / (alphastep_upperedge - alphastep_loweredge));

                //half3 Tex = UNITY_SAMPLE_TEX2D(_MainTex, i.uv).rrr;
                //if (Tex.r < 0.9) discard;
                return fixed4((_Color * (_Glow + 1.0)).rgb, alphastep.r);
            }
            ENDCG
        }
    }
    FallBack "Diffuse"
}