grass.shader

Shader "Custom/PlantShader"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "gray" {}
        _Ambience("Ambience", Float) = 1
    }
    SubShader
    {
        //Tags { "Queue" = "AlphaTest" "RenderType" = "Transparent" }
        Tags{ "Queue" = "Transparent" "RenderType" = "TransparentCutout" }
        Blend SrcAlpha OneMinusSrcAlpha
        LOD 200
        ZWrite Off

        Pass
        {
            //Cull Front
            Cull Off
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

           #pragma target 5.0
            #include "UnityCG.cginc"
            #include "Lighting.cginc"

           // make fog work
           #pragma multi_compile_fwdbase nolightmap nodirlightmap nodynlightmap multi_compile_fog

           // shadow helper functions and macros
           #include "AutoLight.cginc"

           struct VertexData {
               float3 Vertex;
               float2 UV;
               float3 Normal;
           };

           uniform StructuredBuffer<VertexData> _Vertex;

           float _Ambience;

           struct v2f
           {
               float2 uv : TEXCOORD0;
               //UNITY_FOG_COORDS(1)
               SHADOW_COORDS(2) // put shadows data into TEXCOORD1
               float4 pos : SV_POSITION;
               fixed3 diff : COLOR0;
               fixed3 ambient : COLOR1;
               fixed3 diff_rev : COLOR2;
               fixed3 ambient_rev : COLOR3;
               float4 worldPos : TEXCOORD3;

               half3 worldNormal : NORMAL;
               half3 worldNormal_rev : NORMAL1;
           };

           sampler2D _MainTex;
           float4 _MainTex_ST;

            v2f vert(uint id : SV_VertexID)
            {
               v2f o;

               float4 in_v = float4(_Vertex[id].Vertex, 1);

               o.pos = UnityObjectToClipPos(in_v);
               o.uv = TRANSFORM_TEX(_Vertex[id].UV, _MainTex);
               //UNITY_TRANSFER_FOG(o, o.pos);

               o.worldPos = mul(unity_ObjectToWorld, in_v);

               half3 worldNorm = UnityObjectToWorldNormal(_Vertex[id].Normal);;
               

               // diffuse and ambient lighting.
               half nl = max(0, dot(-worldNorm, _WorldSpaceLightPos0.xyz));
               o.diff = nl * _LightColor0.rgb;
               o.ambient = ShadeSH9(half4(-worldNorm, 1)) + _Ambience;
               o.worldNormal = -worldNorm;


               nl = max(0, dot(worldNorm, _WorldSpaceLightPos0.xyz));
               o.diff_rev = nl * _LightColor0.rgb;
               o.ambient_rev = ShadeSH9(half4(worldNorm, 1)) + _Ambience;
               o.worldNormal_rev = worldNorm;

               // compute shadows data
               TRANSFER_SHADOW(o)

               return o;
            }

            fixed4 frag(v2f i, half facing : VFACE) : SV_Target
            {
               // sample the texture
               //fixed4 col = fixed4(0.5, 0.5, 0.5, 0.5);//tex2D(_MainTex, i.uv);
               fixed4 col = tex2D(_MainTex, i.uv);

               fixed3 diff = i.diff;
               fixed3 ambient = i.ambient;
               half3 normal = i.worldNormal;

               if (facing < 0.5) {
                  normal = i.worldNormal_rev;
                  diff = i.diff_rev;
                  ambient = i.ambient_rev;
               }

               // compute shadow attenuation (1.0 = fully lit, 0.0 = fully shadowed)
               fixed shadow = SHADOW_ATTENUATION(i);
               // darken light's illumination with shadow, keep ambient intact
               fixed3 lighting = diff * shadow + ambient;
               col.rgb *= lighting;

               // apply fog
               //UNITY_APPLY_FOG(i.fogCoord, col);
               return col;
            }
            ENDCG
        }
    }
}