Shader "Unlit/shadow"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100

        Pass
        {
            CGPROGRAM

            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_fog

            #include "UnityCG.cginc"
			#include "AutoLight.cginc"

			//UNITY_DECLARE_SHADOWMAP(_ShadowMapTexture);
			//uniform sampler2D _ShadowMapTexture;
			uniform sampler2D m_ShadowmapCopy;

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

            struct v2f
            {
                float2 uv : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                float4 vertex : SV_POSITION;
				float4 _ShadowCoord: TEXCOORD2;
				float3 _worldpos : TEXCOORD3;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                UNITY_TRANSFER_FOG(o,o.vertex);
				o._worldpos = mul(unity_ObjectToWorld, v.vertex);
				//o._ShadowCoord = ComputeScreenPos(o.vertex); //mul(unity_WorldToShadow[0], o._worldpos);
				o._ShadowCoord =  mul(unity_WorldToShadow[1], o._worldpos);
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // sample the texture
                fixed4 col = tex2D(_MainTex, i.uv);
				//float depth = tex2Dproj(_ShadowMapTexture, UNITY_PROJ_COORD(i._ShadowCoord)).x;
				//float depth = tex2Dproj(_ShadowMapTexture, i._ShadowCoord).x;
				//depth = Linear01Depth(depth);
				//col = max(depth > (i._ShadowCoord.z / i._ShadowCoord.w), _LightShadowData.x);
				//col = depth;
				//float shadowAttenuation = UnitySampleShadowmap(
				//	mul(unity_WorldToShadow[0], float4(i._worldpos, 1))
				//);
				float depth = tex2D(m_ShadowmapCopy, i.uv).r;
				//float depth = tex2D(m_ShadowmapCopy, i._ShadowCoord.xy).r;
				//float depth = tex2Dproj(m_ShadowmapCopy, UNITY_PROJ_COORD(i._ShadowCoord)).x;
				//depth = Linear01Depth(depth);
				col = depth;
				col.w = 1;
				return col;
                // apply fog
                UNITY_APPLY_FOG(i.fogCoord, col);
                return col;
            }
            ENDCG
        }
    }
}