Shader "Hidden/VolumetricLights/TransparentDepthWrite"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _Color ("Color", Color) = (1,1,1)
    }
    SubShader
    {
        ColorMask A
        ZWrite Off
        Cull Off

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
            };

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

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.depth = o.vertex.zw;
                return o;
            }

            half4 frag (v2f i) : SV_Target
            {
                half4 color = half4(1, 1, 1, i.depth.x/i.depth.y);
                return color;
            }
            ENDCG
        }
    }
}