smesh/src/Tools/blocFissure/gmu/projettePointSurCourbe.py
2014-01-09 14:20:44 +00:00

59 lines
1.6 KiB
Python

# -*- coding: utf-8 -*-
from geomsmesh import geompy
import logging
import math
# -----------------------------------------------------------------------------
# --- projection d'un point sur une courbe.
def projettePointSurCourbe(pt, edge):
"""
projection d'un point p sur une courbe c
on suppose que la distance (c(u), p) passe par un minimum quand u varie entre 0 et 1
et qu'elle presente pas de minimum local
"""
#logging.debug("start")
dist = []
nbSlices = 50
du = 1.0/nbSlices
for i in range(nbSlices + 1):
p = geompy.MakeVertexOnCurve(edge, du*i)
d = geompy.MinDistance(p,pt)
dist.append((d,i))
dist.sort()
#logging.debug("dist %s", dist)
umin = du*dist[0][1]
umax = du*dist[1][1]
#umin = 0.0
#umax = 1.0
tol = 1.e-8
pmin = geompy.MakeVertexOnCurve(edge, umin)
pmax = geompy.MakeVertexOnCurve(edge, umax)
dmin = geompy.MinDistance(pmin,pt)
dmax = geompy.MinDistance(pmax,pt)
dext = geompy.MinDistance(pmin,pmax)
i=0
while dext > tol and i < 100 :
i = i+1
utest = (umax + umin) / 2.0
ptest = geompy.MakeVertexOnCurve(edge, utest)
dtest = geompy.MinDistance(ptest,pt)
if dmin < dmax:
umax = utest
pmax = ptest
dmax = dtest
else:
umin = utest
pmin = ptest
dmin = dtest
dext = geompy.MinDistance(pmin,pmax)
#logging.debug('umin=%s umax=%s dmin=%s dmax=%s dtest=%s dext=%s', umin,umax,dmin,dmax,dtest,dext)
if abs(utest) < 1.e-7:
utest = 0.0
if abs(1.0-utest) < 1.e-7:
utest = 1.0
logging.debug('u=%s, nbiter=%s dtest=%s dext=%s',utest,i,dtest,dext)
return utest