cmontesano/select_loop.py

## select_loop.py
"""
This is a python port of my old Select Loop C++ plugin for Cinema 4D. Rather
than porting this to R20 and recompiling, distributing, etc I decided to port
it to Python for use as a Script manager plugin.
Just import this script into your Script Manager and add it to a toolbar
or assign a shortcut.

MIT License

Copyright 2019 Christopher Montesano

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is furnished
to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""

import c4d
from c4d.utils import Neighbor
from c4d import gui


def get_opposite_edge(poly, p1, p2):
    if (p1 == p2):
        return None

    if (poly.c == poly.d):  # triangle
        return None

    points = (p1, p2)

    if poly.a in points and poly.b in points:
        return poly.c, poly.d

    if poly.b in points and poly.c in points:
        return poly.a, poly.d

    if poly.c in points and poly.d in points:
        return poly.a, poly.b

    if poly.d in points and poly.a in points:
        return poly.b, poly.c

    return None


def get_shared_points(poly1, poly2):
    shared_points = set()
    for pta in (poly1.a, poly1.b, poly1.c, poly1.d):
        for ptb in  (poly2.a, poly2.b, poly2.c, poly2.d):
            if pta == ptb:
                shared_points.add(pta)
    return list(shared_points)


def select_poly_loop(obj, nth=1, sim=False):
    if obj is None:
        raise ValueError("No object selected")

    if not isinstance(obj, c4d.PolygonObject):
        raise ValueError("Not a polygon object")

    cply = obj.GetPolygonCount()
    cpnt = obj.GetPointCount()
    bsel = obj.GetPolygonS()

    if cply == 0:
        raise ValueError("No polygons found")
    if bsel.GetCount() != 2:
        raise ValueError("Exactly two polygons must be selected")

    plys = obj.GetAllPolygons()

    selected_ids = []
    for index, selected in enumerate(bsel.GetAll(cply)):
        if not selected:
            continue
        selected_ids.append(index)

    assert(len(selected_ids) == 2)

    poly1 = plys[selected_ids[0]]
    poly2 = plys[selected_ids[1]]

    shared_points = get_shared_points(poly1, poly2)
    if len(shared_points) != 2:
        raise ValueError("Selected polygons must share an edge")

    n = Neighbor()
    n.Init(obj)

    for poly_index in range(2):
        this_poly_index = selected_ids[poly_index]
        pt1 = shared_points[0]
        pt2 = shared_points[1]

        for i in range(cply):
            nply = n.GetNeighbor(pt1, pt2, this_poly_index)
            if nply is None:
                break
            this_poly_index = nply
            bsel.Select(nply)
            if i % nth != 0:
                bsel.Toggle(nply)
            opposite_edge = get_opposite_edge(plys[this_poly_index], pt1, pt2)
            if opposite_edge is None:
                break
            pt1, pt2 = opposite_edge
            if pt1 == shared_points[0] and pt2 == shared_points[1]:
                break

    obj.Message(c4d.MSG_CHANGE)
    c4d.EventAdd()


def main():
    nth = gui.InputDialog("Select every nth polygon:", "1")
    nth = int(nth)
    try:
        select_poly_loop(op, nth)
    except ValueError as err:
        gui.MessageDialog(str(err))


if __name__=='__main__':
    main()
	"""
	This is a python port of my old Select Loop C++ plugin for Cinema 4D. Rather
	than porting this to R20 and recompiling, distributing, etc I decided to port
	it to Python for use as a Script manager plugin.
	Just import this script into your Script Manager and add it to a toolbar
	or assign a shortcut.

	MIT License

	Copyright 2019 Christopher Montesano

	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is furnished
	to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in all
	copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
	INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
	PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
	HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
	OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
	SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	"""

	import c4d
	from c4d.utils import Neighbor
	from c4d import gui


	def get_opposite_edge(poly, p1, p2):
	if (p1 == p2):
	return None

	if (poly.c == poly.d): # triangle
	return None

	points = (p1, p2)

	if poly.a in points and poly.b in points:
	return poly.c, poly.d

	if poly.b in points and poly.c in points:
	return poly.a, poly.d

	if poly.c in points and poly.d in points:
	return poly.a, poly.b

	if poly.d in points and poly.a in points:
	return poly.b, poly.c

	return None


	def get_shared_points(poly1, poly2):
	shared_points = set()
	for pta in (poly1.a, poly1.b, poly1.c, poly1.d):
	for ptb in (poly2.a, poly2.b, poly2.c, poly2.d):
	if pta == ptb:
	shared_points.add(pta)
	return list(shared_points)


	def select_poly_loop(obj, nth=1, sim=False):
	if obj is None:
	raise ValueError("No object selected")

	if not isinstance(obj, c4d.PolygonObject):
	raise ValueError("Not a polygon object")

	cply = obj.GetPolygonCount()
	cpnt = obj.GetPointCount()
	bsel = obj.GetPolygonS()

	if cply == 0:
	raise ValueError("No polygons found")
	if bsel.GetCount() != 2:
	raise ValueError("Exactly two polygons must be selected")

	plys = obj.GetAllPolygons()

	selected_ids = []
	for index, selected in enumerate(bsel.GetAll(cply)):
	if not selected:
	continue
	selected_ids.append(index)

	assert(len(selected_ids) == 2)

	poly1 = plys[selected_ids[0]]
	poly2 = plys[selected_ids[1]]

	shared_points = get_shared_points(poly1, poly2)
	if len(shared_points) != 2:
	raise ValueError("Selected polygons must share an edge")

	n = Neighbor()
	n.Init(obj)

	for poly_index in range(2):
	this_poly_index = selected_ids[poly_index]
	pt1 = shared_points[0]
	pt2 = shared_points[1]

	for i in range(cply):
	nply = n.GetNeighbor(pt1, pt2, this_poly_index)
	if nply is None:
	break
	this_poly_index = nply
	bsel.Select(nply)
	if i % nth != 0:
	bsel.Toggle(nply)
	opposite_edge = get_opposite_edge(plys[this_poly_index], pt1, pt2)
	if opposite_edge is None:
	break
	pt1, pt2 = opposite_edge
	if pt1 == shared_points[0] and pt2 == shared_points[1]:
	break

	obj.Message(c4d.MSG_CHANGE)
	c4d.EventAdd()


	def main():
	nth = gui.InputDialog("Select every nth polygon:", "1")
	nth = int(nth)
	try:
	select_poly_loop(op, nth)
	except ValueError as err:
	gui.MessageDialog(str(err))


	if __name__=='__main__':
	main()