PS.
To find a face normal you can take two vectors that lie on the plane of the triangle face and find the cross-product of these vectors. EG a vector from Vertex 0 to Vertex 1, and a vector from vertex 0 to vertex 2 will give 2 two vectors that lie on the plane of the triangle face. Find the cross product of these 2 vectors and you have the normal in which the trinagle is facing. This calculation will rely on your trinagles all following the same rule of having the vertices defined either clockwise or anti-clockwise as you look at them from the 'front'.
pps. I can't spell 'triangle' properly when typing fast.
To find a face normal you can take two vectors that lie on the plane of the triangle face and find the cross-product of these vectors. EG a vector from Vertex 0 to Vertex 1, and a vector from vertex 0 to vertex 2 will give 2 two vectors that lie on the plane of the triangle face. Find the cross product of these 2 vectors and you have the normal in which the trinagle is facing. This calculation will rely on your trinagles all following the same rule of having the vertices defined either clockwise or anti-clockwise as you look at them from the 'front'.
pps. I can't spell 'triangle' properly when typing fast.