float4 frag(VertexOutput i) : COLOR {

//normal direction calculations
     float3 normalDirection = normalize(i.normalDir);

     float3 lightDirection = normalize(lerp(_WorldSpaceLightPos0.xyz, _WorldSpaceLightPos0.xyz
 - i.posWorld.xyz,_WorldSpaceLightPos0.w));

     float3 lightReflectDirection = reflect( -lightDirection, normalDirection );

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

     float3 viewReflectDirection = normalize(reflect( -viewDirection, normalDirection ));

     float3 halfDirection = normalize(viewDirection+lightDirection); 

     float NdotL = max(0.0, dot( normalDirection, lightDirection ));

     float NdotH =  max(0.0,dot( normalDirection, halfDirection));

     float NdotV =  max(0.0,dot( normalDirection, viewDirection));

     float VdotH = max(0.0,dot( viewDirection, halfDirection));

     float LdotH =  max(0.0,dot(lightDirection, halfDirection));
 
     float LdotV = max(0.0,dot(lightDirection, viewDirection)); 

     float RdotV = max(0.0, dot( lightReflectDirection, viewDirection ));

     float attenuation = LIGHT_ATTENUATION(i);

     float3 attenColor = attenuation * _LightColor0.rgb;