I have a obj file which has Vertex Normals. I know that Vertex Normals are used for lighting. The only thing I can find on the internet about Vertex Normals is calculating the vertex normal which is already given in the file. What am I supposed to do with the Normal and the face?
The normals are used when calculating lighting, among other things.
Illumination Model (http://nccastaff.bournemouth.ac.uk/jmacey/CGF/slides/IlluminationModels4up.pdf)