Shader "Unlit/TextureGlow"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _Color ("Color", Color) = (0.0, 0.0, 0.0, 0.0)
        _Glow ("Glow", Range (0.0, 1.0)) = 0.5
    }
    SubShader
    {
        Tags { "Queue" = "Transparent" }
        Blend SrcAlpha OneMinusSrcAlpha ZWrite On

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 2.0

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            sampler2D _MainTex;
            // Needed for TRANSFORM_TEX
            float4 _MainTex_ST;
            fixed4 _Color;
            float _Glow;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // sample the texture
                fixed4 col = tex2D(_MainTex, i.uv);
                // blend color
                col = (col * (1.0 - _Glow) + _Color * _Glow);

                col.a = _Color.a;

                return col;
            }
            ENDCG
        }
    }
}