// Upgrade NOTE: commented out 'float4 unity_LightmapST', a built-in variable
// Upgrade NOTE: commented out 'sampler2D unity_Lightmap', a built-in variable
// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'
// Upgrade NOTE: replaced tex2D unity_Lightmap with UNITY_SAMPLE_TEX2D

Shader "M/Terrain Mesh" {
	Properties {
		_SplatTex ("Splat (RGBA)", 2D) = "white" {}
		_Layer1("Layer 1 (RGB)", 2D) = "white" {}
		_Layer2("Layer 2 (RGB)", 2D) = "white" {}
		_Layer3("Layer 3 (RGB)", 2D) = "white" {}
		_Layer4("Layer 4 (RGB)", 2D) = "white" {}

	}
	SubShader {
		Tags { "Queue"="Geometry" "RenderType"="Opaque"}
		LOD 200
		
		Pass {

			CGPROGRAM
			
			#pragma vertex vert
			#pragma fragment frag

			#include "UnityCG.cginc"


			sampler2D _SplatTex;
			sampler2D _Layer1;
			sampler2D _Layer2;
			sampler2D _Layer3;
			sampler2D _Layer4;
			// sampler2D	 unity_Lightmap; //Far lightmap.
			// float4	 unity_LightmapST; //Lightmap atlasing data.
			float4 unity_LightmapIndST;
			float4 _Layer1_ST;
			float4 _Layer2_ST;
			float4 _Layer3_ST;
			float4 _Layer4_ST;


 
			struct appdata {
				float4 vertex : POSITION;
				float4 normal : NORMAL;
				float4 texcoord : TEXCOORD0;
				float4 texcoord1 : TEXCOORD1;
			};
			
			struct v2f {
				float4  pos : SV_POSITION;
				float2  uv : TEXCOORD0;
				float2 lightmapUV : TEXCOORD1;
				float2 uvLayer1 : TEXCOORD2;
				float2 uvLayer2 : TEXCOORD3;
				float2 uvLayer3 : TEXCOORD4; 
				float2 uvLayer4 : TEXCOORD5;
			};

			

 
			v2f vert (appdata v)
			{ 
				v2f o;
		
				o.pos = UnityObjectToClipPos (v.vertex);
				o.uv = v.texcoord.xy;
				o.lightmapUV = v.texcoord1.xy * unity_LightmapST.xy + unity_LightmapST.zw;
				o.uvLayer1 = TRANSFORM_TEX(v.texcoord, _Layer1);
				o.uvLayer2 = TRANSFORM_TEX(v.texcoord, _Layer2);
				o.uvLayer3 = TRANSFORM_TEX(v.texcoord, _Layer3);
				o.uvLayer4 = TRANSFORM_TEX(v.texcoord, _Layer4);
				
				return o;
			}

			float4 getLayerColor(sampler2D layer, float2 uv, float weight)
			{
				return tex2D(layer, uv) * weight;
			}
 
			fixed4 frag (v2f i) : COLOR
			{
			
				float4 weights = tex2D(_SplatTex, i.uv);
				float4 layersColor = getLayerColor(_Layer1, i.uvLayer1.xy, weights.x);
				layersColor += getLayerColor(_Layer2, i.uvLayer2.xy, weights.y);
				layersColor += getLayerColor(_Layer3, i.uvLayer3.xy, weights.z);
				layersColor += getLayerColor(_Layer4, i.uvLayer4.xy, weights.w);
				 
				
				fixed4 light = UNITY_SAMPLE_TEX2D (unity_Lightmap, i.lightmapUV);
				light.xyz = DecodeLightmap(light);
				light.w = 1;



	
				return (layersColor * light);

			}

			ENDCG
		}
	} 
}