barycentric Coordinates

barycentric_coordinates will give the coordinates alpha, beta ,gama of the matrix face_point.

face_point is the point [x,y]' from the mean shape of the face. dt is 3 by 2 matrix that will have the coordinates corresponding 2 the vertices of a triangle. for eg for a triangle with vertices [v1, v2, v3] v1 will have coordinates [x1,y1] so dt will contain the matrix [x1 y1; x2 y2; x3 y3]