Internal spherical flippping function
spherical.flipping(C, mesh, param1, param2)
numeric: coordinates of the point of view
object of class mesh3d
numeric: first parameter for spherical flipping (usually ranged from 0.1 to 3, try!)
numeric second paramter for spherical flipping (don't change it!)
Antonio Profico, Costantino Buzi, Marina Melchionna, Paolo Piras, Pasquale Raia, Alessio Veneziano
Profico, A., Schlager, S., Valoriani, V., Buzi, C., Melchionna, M., Veneziano, A., ... & Manzi, G. (2018). Reproducing the internal and external anatomy of fossil bones: Two new automatic digital tools. American Journal of Physical Anthropology, 166(4), 979-986.#' @export
Katz, S., Tal, A., & Basri, R. (2007). Direct visibility of point sets. In ACM SIGGRAPH 2007 papers (pp. 24-es).