float grazingTerm = saturate(roughness + _Metallic);
float3 unityIndirectSpecularity =  indirectSpecular * FresnelLerp(specColor,grazingTerm,NdotV) * 
max(0.15,_Metallic) * (1-roughness*roughness* roughness);

float3 lightingModel = (diffuseColor + specularity 
+ (unityIndirectSpecularity *_UnityLightingContribution));