Shader "UnityCommunity/Sprites/SpriteDropShadow"
{
    Properties
    {
        [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
        _Color ("Tint", Color) = (1,1,1,1)
        [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
        _ShadowColor ("Shadow", Color) = (0,0,0,1)
        _ShadowOffset ("ShadowOffset", Vector) = (0,-0.1,0,0)
    }
    SubShader
    {
        Tags
        {
            "Queue"="Transparent"
            "IgnoreProjector"="True"
            "RenderType"="Transparent"
            "PreviewType"="Plane"
            "CanUseSpriteAtlas"="True"
        }
        Cull Off
        Lighting Off
        ZWrite Off
        Blend One OneMinusSrcAlpha
        // draw shadow
        Pass
        {
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile _ PIXELSNAP_ON
            #include "UnityCG.cginc"

            struct appdata_t
            {
                float4 vertex   : POSITION;
                float4 color    : COLOR;
                float2 texcoord : TEXCOORD0;
            };
            struct v2f
            {
                float4 vertex   : SV_POSITION;
                fixed4 color    : COLOR;
                float2 texcoord  : TEXCOORD0;
            };

            fixed4 _Color;
            fixed4 _ShadowColor;
            float4 _ShadowOffset;
            v2f vert(appdata_t IN)
            {
                v2f OUT;
                OUT.vertex = UnityObjectToClipPos(IN.vertex+_ShadowOffset);
                OUT.texcoord = IN.texcoord;
                OUT.color = IN.color *_ShadowColor;
                #ifdef PIXELSNAP_ON
                OUT.vertex = UnityPixelSnap (OUT.vertex);
                #endif
                return OUT;
            }
            sampler2D _MainTex;
            sampler2D _AlphaTex;
            float _AlphaSplitEnabled;
            fixed4 SampleSpriteTexture (float2 uv)
            {
                fixed4 color = tex2D (_MainTex, uv);
                color.rgb = _ShadowColor.rgb;
                #if UNITY_TEXTURE_ALPHASPLIT_ALLOWED
                if (_AlphaSplitEnabled)
                    color.a = tex2D (_AlphaTex, uv).r;
                #endif //UNITY_TEXTURE_ALPHASPLIT_ALLOWED
                return color;
            }
            fixed4 frag(v2f IN) : SV_Target
            {
                fixed4 c = SampleSpriteTexture (IN.texcoord) * IN.color;
                c.rgb *= c.a;
                return c;
            }
        ENDCG
        }
        // draw real sprite
        Pass
        {
        CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile _ PIXELSNAP_ON
            #include "UnityCG.cginc"

            struct appdata_t
            {
                float4 vertex   : POSITION;
                float4 color    : COLOR;
                float2 texcoord : TEXCOORD0;
            };
            struct v2f
            {
                float4 vertex   : SV_POSITION;
                fixed4 color    : COLOR;
                float2 texcoord  : TEXCOORD0;
            };

            fixed4 _Color;
            v2f vert(appdata_t IN)
            {
                v2f OUT;
                OUT.vertex = UnityObjectToClipPos(IN.vertex);
                OUT.texcoord = IN.texcoord;
                OUT.color = IN.color * _Color;
                #ifdef PIXELSNAP_ON
                OUT.vertex = UnityPixelSnap (OUT.vertex);
                #endif
                return OUT;
            }
            sampler2D _MainTex;
            sampler2D _AlphaTex;
            float _AlphaSplitEnabled;
            fixed4 SampleSpriteTexture (float2 uv)
            {
                fixed4 color = tex2D (_MainTex, uv);
                #if UNITY_TEXTURE_ALPHASPLIT_ALLOWED
                if (_AlphaSplitEnabled)
                    color.a = tex2D (_AlphaTex, uv).r;
                #endif //UNITY_TEXTURE_ALPHASPLIT_ALLOWED
                return color;
            }
            fixed4 frag(v2f IN) : SV_Target
            {
                fixed4 c = SampleSpriteTexture (IN.texcoord) * IN.color;
                c.rgb *= c.a;
                return c;
            }
        ENDCG
        }
    }
}