# $Id$
##
##  This file is part of pyFormex 0.8.9  (Fri Nov  9 10:49:51 CET 2012)
##  pyFormex is a tool for generating, manipulating and transforming 3D
##  geometrical models by sequences of mathematical operations.
##  Home page: http://pyformex.org
##  Project page:  http://savannah.nongnu.org/projects/pyformex/
##  Copyright 2004-2012 (C) Benedict Verhegghe (benedict.verhegghe@ugent.be) 
##  Distributed under the GNU General Public License version 3 or later.
##
##
##  This program is free software: you can redistribute it and/or modify
##  it under the terms of the GNU General Public License as published by
##  the Free Software Foundation, either version 3 of the License, or
##  (at your option) any later version.
##
##  This program is distributed in the hope that it will be useful,
##  but WITHOUT ANY WARRANTY; without even the implied warranty of
##  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
##  GNU General Public License for more details.
##
##  You should have received a copy of the GNU General Public License
##  along with this program.  If not, see http://www.gnu.org/licenses/.
##

"""Slice

This example illustrates the 'cutWithPlane' method applied on a
surface and the animation of the results.

A model of a horse is repeatedly cut by a plane and the cut-off parts
are rotated and translated.
"""
from __future__ import print_function
_status = 'checked'
_level = 'advanced'
_topics = ['surface']
_techniques = ['color','widgets','animation']

from gui.draw import *
from plugins.trisurface import TriSurface

def askSlices(bb):
    res = askItems([('Direction',0),
                    ('# slices',15),
                    ('total rot',70.),
                   ],caption = 'Define the slicing planes')
    if res:
        axis = res['Direction']
        nslices = res['# slices']
        totalrot = res['total rot']
        xmin,xmax = bb[:,axis]
        dx =  (xmax-xmin) / nslices
        x = arange(nslices+1) * dx
        N = unitVector(axis)
        P = [ bb[0]+N*s for s in x ]
        return P,N,totalrot
    else:
        return None


def run():
    reset()
    smooth()
    lights(True)
    transparent(False)
    setView('horse',[20,20,0])
    S = TriSurface.read(getcfg('datadir')+'/horse.off')
    bb = S.bbox()

    t = -0.3
    bb[0] = (1.0-t)*bb[0] + t*bb[1]
    draw(S,bbox=bb,view='front')

    try:
        P,n,t = askSlices(S.bbox())
    except:
        return

    a = t/len(P)

    F = S.toFormex()
    G = []
    old = seterr(all='ignore')
    setDrawOptions({'bbox':None})

    clear()
    A = None
    for i,p in enumerate(P):
        F1,F = F.cutWithPlane(p,-n)
        if F1.nelems() > 0:
            F1.setProp(i)
        G = [ g.rot(a,around=p) for g in G ] 
        G.append(F1)
        #clear()
        B = draw([F,G])
        if A:
            undraw(A)
        A = B
            
    seterr(**old)

    x = pf.canvas.width()/2
    y = pf.canvas.height() - 40
    T = drawText("No animals got hurt during the making of this movie!",x,y,size=18,gravity='C')
    for i in range(10):
        sleep(0.3)
        undecorate(T)
        sleep(0.3)
        decorate(T)

if __name__ == 'draw':
    run()
# End
