// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)

Shader "Hidden/Nature/Lux Tree Creator Leaves Rendertex" {
Properties {
    _TranslucencyColor ("Translucency Color", Color) = (0.73,0.85,0.41,1) // (187,219,106,255)
    _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
    _HalfOverCutoff ("0.5 / alpha cutoff", Range(0,1)) = 1.0
    _TranslucencyViewDependency ("View dependency", Range(0,1)) = 0.7

    _MainTex ("Base (RGB) Alpha (A)", 2D) = "white" {}
    _BumpSpecMap ("Normalmap (GA) Spec (R) Shadow Offset (B)", 2D) = "bump" {}
    _TranslucencyMap ("Trans (B) Gloss(A)", 2D) = "white" {}
}

SubShader {

    Pass {
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
#include "UnityBuiltin3xTreeLibrary.cginc"

struct v2f {
    float4 pos : SV_POSITION;
    float2 uv : TEXCOORD0;
    float3 color : TEXCOORD1;
    float3 backContrib : TEXCOORD2;
    float3 nl : TEXCOORD3;
    float3 nh : TEXCOORD4;

    half3 ambient : TEXCOORD5;

    UNITY_VERTEX_OUTPUT_STEREO
};

CBUFFER_START(UnityTerrainImposter)
    float3 _TerrainTreeLightDirections[4];
    float4 _TerrainTreeLightColors[4];
CBUFFER_END


v2f vert (appdata_full v) {
    v2f o;
    UNITY_SETUP_INSTANCE_ID(v);
    UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
    ExpandBillboard (UNITY_MATRIX_IT_MV, v.vertex, v.normal, v.tangent);
    o.pos = UnityObjectToClipPos(v.vertex);
    o.uv = v.texcoord.xy;
    float3 viewDir = normalize(ObjSpaceViewDir(v.vertex));

    for (int j = 0; j < 3; j++)
    {
        float3 lightDir = _TerrainTreeLightDirections[j];

        half nl = dot (v.normal, lightDir);

        // view dependent back contribution for translucency
        half backContrib = saturate(dot(viewDir, -lightDir));

        // normally translucency is more like -nl, but looks better when it's view dependent
        backContrib = lerp(saturate(-nl), backContrib, _TranslucencyViewDependency);
        o.backContrib[j] = backContrib * 2;

        // wrap-around diffuse
        nl = max (0, nl * 0.6 + 0.4);
//nl = saturate(nl);        
        o.nl[j] = nl;

        half3 h = normalize (lightDir + viewDir);
        float nh = max (0, dot (v.normal, h));
        o.nh[j] = nh;
    }
    o.color = v.color.a;
    o.ambient = ShadeSH9(half4 (v.normal, 1));
    return o;
}

sampler2D _MainTex;
sampler2D _BumpSpecMap;
sampler2D _TranslucencyMap;
fixed _Cutoff;

half3 CalcTreeLighting(half3 lightColor, fixed3 albedo, half backContrib, half nl, half nh, half specular, half gloss)
{
    half3 translucencyColor = backContrib * _TranslucencyColor;

    half spec = pow (nh, specular) * gloss;
    return (albedo * (translucencyColor + nl) + _SpecColor.rgb * spec) * lightColor;
}

fixed4 frag (v2f i) : SV_Target {
    fixed4 col = tex2D (_MainTex, i.uv);
    clip (col.a - _Cutoff);

    fixed3 albedo = col.rgb;

    half specular = tex2D (_BumpSpecMap, i.uv).r * 128.0;

    fixed4 trngls = tex2D (_TranslucencyMap, i.uv);
    half gloss = trngls.a;

    //half3 light = UNITY_LIGHTMODEL_AMBIENT * albedo;
    half3 light = i.ambient * albedo * i.color;
    half3 backContribs = i.backContrib * trngls.b;

    light += CalcTreeLighting(_TerrainTreeLightColors[0].rgb, albedo, backContribs.x, i.nl.x, i.nh.x, specular, gloss);
    light += CalcTreeLighting(_TerrainTreeLightColors[1].rgb, albedo, backContribs.y, i.nl.y, i.nh.y, specular, gloss);
    light += CalcTreeLighting(_TerrainTreeLightColors[2].rgb, albedo, backContribs.z, i.nl.z, i.nh.z, specular, gloss);

    fixed4 c;
    c.rgb = light;

    c.a = 1;

    return c;
}
ENDCG
    }
}

FallBack Off
}
