#ifndef SGAME_VLIGHT_INCLUDED
#define SGAME_VLIGHT_INCLUDED
	#if defined(_ANISOGGX_ON)
		inline half D_GGXAniso_SGame(half TdotH, half BdotH, half mt, half mb, half nh) 
		{
			half d = TdotH * TdotH / (mt * mt) + BdotH * BdotH / (mb * mb) + nh * nh;
			return (1.0 / (3.14159 * mt * mb * d * d));
		}
		inline half V_SmithJointGGXAniso_SGame(half TdotV, half BdotV, half NdotV, half TdotL, half BdotL, half NdotL, half roughnessT, half roughnessB) 
		{
			half lambdaV = NdotL * sqrt(roughnessT * TdotV * TdotV + roughnessB * BdotV * BdotV + NdotV * NdotV);
			half lambdaL = NdotV * sqrt(roughnessT * TdotL * TdotL + roughnessB * BdotL * BdotL + NdotL * NdotL);
			return 0.5 / max(1e-5f, (lambdaV + lambdaL));
		}
		inline half GGXSpecularTermAniso_SGame(half3 worldTangent, half3 worldBiTangent, half roughnessT, 
			half roughnessB, half3 halfDir, half3 lightDir, half3 viewDir, half nl, half nh, half nv) 
		{
			half mt = roughnessT;
			half mb = roughnessB;
			half TdotH = dot(worldTangent, halfDir);
			half BdotH = dot(worldBiTangent, halfDir);
			half TdotV = dot(worldTangent, viewDir);
			half BdotV = dot(worldBiTangent, viewDir);
			half TdotL = dot(worldTangent, lightDir);
			half BdotL = dot(worldBiTangent, lightDir);
			half D = D_GGXAniso_SGame(TdotH, BdotH, mt, mb, nh);
			half V = V_SmithJointGGXAniso_SGame(TdotV, BdotV, nv, TdotL, BdotL, nl, mt, mb);
			half specularTerm = (V * D) * 3.14159;

			return clamp(specularTerm, 0, 10);
		}
	#endif
	#define VLIGHT_BY_PERCEPTUALROUGHNESS 1
	inline half3 VLightDiffuse(half3 normal)
	{
		half3 lightDir = GetMainLight().direction;
		half3 NDotL = saturate( dot(normal, lightDir) );
		NDotL = 0.444 + NDotL * 0.556;
		half3 lightColor = 1;
		half3 vLightDiff =  lightColor * NDotL;
		return vLightDiff;
	}

	inline half3 Unreal4SpecBRDF_Simple(half roughness, half3 normal, half3 viewDir, half3 lightDir,  half3 specularColor, half3 diffuseTerm )
	{
		roughness = max(0.08, roughness);
		half3 H = normalize(viewDir + lightDir);
		half NoH = saturate(dot(normal, H));
		half m2 = roughness * roughness;
		m2 *= m2;
		half D = (NoH * m2 - NoH) * NoH + 1;
		D = D * D + (1e-06);
		D = (0.25 * m2) / D;
		half3 specLighting = specularColor * D * diffuseTerm;
		return specLighting;
	}

	#define SGameVLightDiffuse VLightDiffuse
	#define VLightSpecular Unreal4SpecBRDF_Simple
	inline half3 SGameVLightSpecular(half roughness, half3 normal, half3 viewDir,  half3 specularColor, half3 diffuseTerm)
	{
		half3 lightDir = GetMainLight().direction;
		roughness = max(roughness, 0.3);
		return VLightSpecular(roughness, normal, viewDir, lightDir,  specularColor, diffuseTerm);
	}

	#if defined(_ANISOGGX_ON)
		inline half3 SGameVLightSpecularAniso(half roughness, half3 normal, half3 viewDir,  half3 specularColor, half3 diffuseTerm, half3 worldTangent, half3 worldBitangent)
		{
			half3 lightDir = GetMainLight().direction;
		    half3 halfDir = normalize (lightDir + GetMainLight().direction);
			half nl = dot(normal, lightDir);
		    half nh = saturate(dot(normal, halfDir));
		    half nv = dot(normal, viewDir);
			return GGXSpecularTermAniso_SGame(worldTangent, worldBitangent, roughness, 0, halfDir, lightDir, GetMainLight().direction, nl, nh, nv);
		}
	#endif
#endif //SGAME_VLIGHT_INCLUDED