Given a list of vertices and faces, generate the normals for a triangle mesh.
Given an array of triangles' vertices, return a
Float32Array of their normal
vectors. Helpful for quickly calculating the the normals of a mesh (assuming
it's made up of triangles).
Takes an array-like list of
triangles. Each vertex should take up 3 elements,
combined into groups of 3 to make each triangle. Optionally, you can pass in
output object to set the values directly. If not, a
Float32Array will be created for you - either way, the new/updated array will