Shader "MyShader/PDRDiffuse4"
{
	Properties
	{
		_Color("MainColor", Color) = (0.5,0.5,0.5,1)
		_MainTex("Base 2D", 2D) = "white"{}
		_MaskTex("Mask 2D", 2D) = "white"{}
		_Normal("Normal", 2D) = "white"{}
		_EmissionRatio("EmissionRatio", Range(0, 30)) = 1
		_RoughnessScale("Roughness Scale", Range(0, 2)) = 1
		_MetallicScale("Metallic Scale", Range(0, 5)) = 1
		_LMcolScale("LMcol Scale", Range(1, 5)) = 1
		_MCScale("MCScale Scale", Range(0, 2)) = 0.5
	}

	SubShader
	{
		LOD 300
		Tags{ "RenderType" = "Opaque" }

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

			struct appdataInput
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
				float2 uv1 : TEXCOORD1;
				float3 normal:NORMAL;
				float4 tangent : TANGENT;
			};

			struct v2f
			{
				float4 pos : SV_POSITION;
				float4 uv : TEXCOORD0;
				float4 posWorld : TEXCOORD1;
				float3 normalDir : TEXCOORD2;
				float3 tangentDir : TEXCOORD3;
				float3 bitangentDir : TEXCOORD4;
				UNITY_FOG_COORDS(5)
			};

			sampler2D _MainTex, _MaskTex, _Normal;
			float _EmissionRatio;
			float4 _Color;
			float4 _GlobalLightColor, _GlobalLightDir;
			half _RoughnessScale, _MetallicScale, _LMcolScale, _MCScale;

			half GGX_Mobile(half Roughness, half NoH)
			{
				float OneMinusNoHSqr = 1.0 - NoH * NoH;

				half a = Roughness * Roughness;
				float n = NoH * a;
				float p = a / (OneMinusNoHSqr + n * n);
				float d = min(32, p * p);
				return d;
			}

			half3 EnvBRDFApprox(half3 SpecularColor, half Roughness, half NoV)
			{
				const half4 c0 = { -1, -0.0275, -0.572, 0.022 };
				const half4 c1 = { 1, 0.0425, 1.04, -0.04 };
				half4 r = Roughness * c0 + c1;
				half a004 = min(r.x * r.x, exp2(-9.28 * NoV)) * r.x + r.y;
				half2 AB = half2(-1.04, 1.04) * a004 + r.zw;

				AB.y *= saturate(50.0 * SpecularColor.g);
				return SpecularColor * AB.x + AB.y;
			}

			v2f vert(appdataInput v)
			{
				v2f o;
				o.posWorld = mul(unity_ObjectToWorld, v.vertex);
				o.pos = mul(UNITY_MATRIX_VP, o.posWorld);
				o.uv.xy = v.uv;
				o.uv.zw = v.uv1.xy * unity_LightmapST.xy + unity_LightmapST.zw;

				o.normalDir = UnityObjectToWorldNormal(v.normal);
				o.tangentDir = normalize(mul((float3x3)unity_ObjectToWorld, v.tangent.xyz));
				o.bitangentDir = cross(o.normalDir, o.tangentDir) * v.tangent.w;

				UNITY_TRANSFER_FOG(o, o.pos);
				return o;
			}

			float4 frag(v2f i) : SV_Target
			{
				float3 mainColor = tex2D(_MainTex, i.uv.xy).rgb;
				mainColor *= mainColor;
				float4 maskColor = tex2D(_MaskTex, i.uv.xy);

				float3 V = normalize(_WorldSpaceCameraPos.xyz - i.posWorld.xyz);

				float3x3 tangentTransform = float3x3(i.tangentDir, i.bitangentDir, i.normalDir);
				float3 N = UnpackNormal(tex2D(_Normal, i.uv.xy));
				N = normalize(mul(N, tangentTransform));

				//float3 R = reflect(-V, i.normalDir);

				float Metallic = maskColor.r * _MetallicScale;
				float Roughness = max(maskColor.g, 0.008) * _RoughnessScale;

				float3 DiffuseColor = mainColor - mainColor * Metallic;
				float3 SpecularColor0 = (0.04 - 0.04 * Metallic) + mainColor * Metallic;

				float3 L = _GlobalLightDir.xyz; //;
				float3 H = normalize(L + V);

				float4 resultColor = 0;
				float NdotL = max(dot(N, L), 0.001);
				float NdotV = max(dot(N, V), 0.001);
				float NdotH = max(dot(N, H), 0.01);

				float3 SpecularColor = SpecularColor0 *0.9;//EnvBRDFApprox(SpecularColor0, Roughness, NdotV);
				float3 specular = SpecularColor * (Roughness * 0.25 + 0.25) * GGX_Mobile(Roughness, NdotH);
				resultColor.rgb = (DiffuseColor + specular) * _GlobalLightColor * NdotL;

				float3 lmCol = DecodeLightmap(UNITY_SAMPLE_TEX2D(unity_Lightmap, i.uv.zw));
				float3 lmGray = Luminance(lmCol.rgb) * _LMcolScale;
				resultColor.rgb += lmCol.rgb * lmCol.rgb * mainColor.rgb * lmGray * lmGray;

				resultColor.rgb += maskColor.b * mainColor * _EmissionRatio;
				resultColor.rgb = sqrt(resultColor.rgb);

				resultColor.rgb *= (_MCScale* _Color.rgb);
				//resultColor = clamp(resultColor, 0.0, 10.0);
				UNITY_APPLY_FOG(i.fogCoord, resultColor);
				resultColor.a = 1;
				return resultColor;
			}
			ENDCG
		}
	}

	Fallback "Diffuse" 
}