Shader "DBV/Kristo/FastGrass2.0"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Texture", 2D) = "white" {}
        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Metallic ("Metallic", Range(0,1)) = 0.0

        [Space]
        _AlphaCutoff ("Alpha cutoff", Range(0,1)) = 0.05

        [Space]
        _WindTexture ("Wind texture", 2D) = "white" {}
        _WindSpeed ("Wind direction", Vector) = (1,1,1,1)
        _HeightStart ("Height start", Float) = 0.05
        _WindStrength ("Wind strength", Float) = 1
        _WindTimeSpeed ("Wind speed", Float) = 1
    }
    SubShader
    {
        Tags { "RenderType"="Transparent" }
        LOD 200
        Cull Off
        ZWrite Off

        CGPROGRAM
        // Physically based Standard lighting model, and enable shadows on all light types
        #pragma surface surf Standard vertex:vert noshadowmask nodynlightmap nodirlightmap nolightmap noshadow

        // Use shader model 3.0 target, to get nicer looking lighting
        #pragma target 3.0

        sampler2D _MainTex,_WindTexture;

        struct Input {
            float2 uv_MainTex;
            };

        half _Glossiness;
        half _Metallic;
        fixed4 _Color;
        float _AlphaCutoff, _HeightStart, _WindStrength, _WindTimeSpeed;
        float4 _WindSpeed;

        // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
        // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
        // #pragma instancing_options assumeuniformscaling
        UNITY_INSTANCING_BUFFER_START(Props)
            // put more per-instance properties here
        UNITY_INSTANCING_BUFFER_END(Props)

        void vert (inout appdata_full v) {
            // get vertex world position
            float4 worldPos = mul(v.vertex, unity_ObjectToWorld);
            float2 samplePos = worldPos.xz;
            samplePos += _Time.x * _WindSpeed.xz;
            float windAmount = tex2Dlod(_WindTexture, float4(samplePos, 0, 0));
            float heightAmount = v.vertex.z > _HeightStart;//v.vertex.y - _HeightStart;
            v.vertex.y += sin(_WindTimeSpeed*windAmount)*_WindStrength * heightAmount;
            v.vertex.x += cos(_WindTimeSpeed*windAmount)*_WindStrength * heightAmount;
            }

        void surf (Input IN, inout SurfaceOutputStandard o)
        {
            // Albedo comes from a texture tinted by color
            fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
            o.Albedo = c.rgb;
            // Metallic and smoothness come from slider variables
            o.Metallic = _Metallic;
            o.Smoothness = _Glossiness;
            clip(c.a-_AlphaCutoff);
            o.Alpha = c.a;
        }
        ENDCG
    }
    FallBack "Diffuse"
}