What i'm trying to do is compare Normal vectors to know if multiple surfaces are positioned at the exact same direction and if not then to be able to tell how close in direction to each other they are by the difference in their Normal values. So thats why i need to know the answers to 1st & 2nd Paragraphs below if that will also help u to help me obtain the answers to the two questions 1st & 2nd below.
So 1st: If i have a negative normal value to use in C++ coding does it also indicate the direction of that surface.
2nd: If i use Cross Product to find the Normal of a Triangle Surface with vertices p1, p2, p3 its gonna look something like this:
A= p2 - p1 & B= p3 - p1
Nx = Ay * Bz - Az * By
Ny = Az * Bx - Ax * Bz
Nz = Ax * By - Ay * Bx
So if for example Nx equals a negative value how would i process it? Cuz to what i understand negative values cannot work cuz normal values are perpendicular to surfaces and have to be positive to be processed with a Light source vector. So what i saw on another post on this site: (OpenGL how to manage negative normals?) was them iqnoring the negative value ( I THINK )and treating it like a positive to give a positve result that can be processed. I could be wrong thats why im trying to clear that up as well.