#! /usr/bin/python3
# Last edited on 2020-03-08 08:54:54 by jstolfi 

# This module provides functions to convert from absolute
# matchstick part placements to parent-relative ones.

# For a description of the matchstick model and of the structure
# of (absolute) placement data, see {nmwk_compute_abs_matchstick_parms.py}

import sys, math, rn, rmxn

def nmwk_model_abs_to_rel(Labs):
  # Each element of {Labs} should be a part placement tuple with the
  # coordinates of the local origin and axis vectors relative to the
  # scene's coordinate system. The first two elements of the placement
  # tuple should be the name of the part and the name of its parent, the
  # proximal body part to which it is attached; or "none" if the part is
  # a /root part/ (has no parent). These parent links must define a
  # forest structure.
  
  # The function returns the list of the same placements, except that
  # the origin and axis vector of each part which has a parent are
  # expressed relative to the local coordinate system of that parent.

  assert False # To be implemented.
  #---------------------------------------------------------------------

def nmwk_part_abs_to_rel(Pabs, Rabs):
  # Given the absolure placement data {Pabs,Rabs} for some
  # part {P} and for its parent part {R}, returns the 
  # placement {Prel} of {P}  relative to {R}. Namely,
  # the origin and axis vectors of {P} are expressed relative to
  # the coordinate system  of {R}.
  
  assert False # To be implemented.
  #---------------------------------------------------------------------