src/Mod/Draft/draftgeoutils/faces.py

# SPDX-License-Identifier: LGPL-2.1-or-later

# ***************************************************************************
# *   Copyright (c) 2009, 2010 Yorik van Havre <yorik@uncreated.net>        *
# *   Copyright (c) 2009, 2010 Ken Cline <cline@frii.com>                   *
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"""Provides various functions to work with faces."""
## @package faces
# \ingroup draftgeoutils
# \brief Provides various functions to work with faces.

import lazy_loader.lazy_loader as lz

import DraftVecUtils
from FreeCAD import Base
from draftgeoutils.geometry import are_coplanar

# Delay import of module until first use because it is heavy
Part = lz.LazyLoader("Part", globals(), "Part")

## \addtogroup draftgeoutils
# @{


def concatenate(shape):
    """Turn several faces into one."""
    boundary_edges = getBoundary(shape)
    sorted_edges = Part.sortEdges(boundary_edges)

    try:
        wires = [Part.Wire(edges) for edges in sorted_edges]
        face = Part.makeFace(wires, "Part::FaceMakerBullseye")
    except Base.FreeCADError:
        print(
            "DraftGeomUtils: Fails to join faces into one. "
            + "The precision of the faces would be insufficient"
        )
        return shape
    else:
        if not wires[0].isClosed():
            return wires[0]
        else:
            return face


def getBoundary(shape):
    """Return the boundary edges of a group of faces."""
    if isinstance(shape, list):
        shape = Part.makeCompound(shape)

    # Make a lookup-table where we get the number of occurrences
    # to each edge in the fused face
    table = dict()
    for f in shape.Faces:
        for e in f.Edges:
            hash_code = e.hashCode()
            if hash_code in table:
                table[hash_code] = table[hash_code] + 1
            else:
                table[hash_code] = 1

    # Filter out the edges shared by more than one sub-face
    bound = list()
    for e in shape.Edges:
        if table[e.hashCode()] == 1:
            bound.append(e)
    return bound


def is_coplanar(faces, tol=-1):
    """Return True if all faces in the given list are coplanar.

    Parameters
    ----------
    faces: list
        List of faces to check coplanarity.
    tol: float, optional
        It defaults to `-1`, the tolerance of confusion, equal to 1e-7.
        Is the maximum deviation to be considered coplanar.

    Returns
    -------
    out: bool
        True if all face are coplanar. False in other case.
    """

    first_face = faces[0]
    for face in faces:
        if not are_coplanar(first_face, face, tol):
            return False

    return True


isCoplanar = is_coplanar


def bind(w1, w2, per_segment=False):
    """Bind 2 wires by their endpoints and returns a face / compound of faces.

    If per_segment is True and the wires have the same number of edges, the
    wires are processed per segment: a separate face is created for each pair
    of edges (one from w1 and one from w2), and the faces are then fused. This
    avoids problems with walls based on wires that selfintersect, or that have
    a loop that ends in a T-connection (f.e. a wire shaped like a number 6).
    """

    def create_face(w1, w2):

        try:
            w3 = Part.LineSegment(w1.Vertexes[0].Point, w2.Vertexes[0].Point).toShape()
            w4 = Part.LineSegment(w1.Vertexes[-1].Point, w2.Vertexes[-1].Point).toShape()
        except Part.OCCError:
            print("DraftGeomUtils: unable to bind wires")
            return None
        if w3.section(w4).Vertexes:
            print("DraftGeomUtils: Problem, a segment is self-intersecting, please check!")
        f = Part.Face(Part.Wire(w1.Edges + [w3] + w2.Edges + [w4]))
        return f

    if not w1 or not w2:
        print("DraftGeomUtils: unable to bind wires")
        return None

    if per_segment and len(w1.Edges) > 1 and len(w1.Edges) == len(w2.Edges):
        faces = []
        faces_list = []
        for edge1, edge2 in zip(w1.Edges, w2.Edges):
            # Find touching edges due to ArchWall Align in opposite
            # directions, and/or opposite edge orientations.
            #
            # w1 o-----o            w1 o-----o            w1 o-----o
            #          | w1                  |                     |
            # w2 +-----x-----o w1   w2 +-----+            w2 +-----+
            #       w2 |                  w2 | w1               w2 | w1
            #          +-----+ w2            o-----o w1            +-----+ w2
            #                                |                     |
            #                                +-----+ w2            o-----o w1
            #
            # TODO Maybe those edge pair should not be generated in offsetWire()
            #      and separate wires should then be returned.

            # If edges touch the Shape.section() compound will have 1 or 2 vertexes:
            if edge1.section(edge2).Vertexes:
                faces_list.append(faces)  # Break into separate list
                faces = []  # Reset original faces variable
                continue  # Skip the touching edge pair
            else:
                face = create_face(edge1, edge2)
                if face is None:
                    return None
                faces.append(face)

        # Usually there is last series of face after above 'for' routine,
        # EXCEPT when the last edge pair touch, faces had been appended
        # to faces_list, and reset faces =[]
        #
        # TODO Need fix further anything if there is a empty [] in faces_list ?
        #
        if faces_list and faces:
            # if wires are closed, 1st & last series of faces might be connected
            # except when
            # 1) there are only 2 series, connecting would return invalid shape
            # 2) 1st series of faces happens to be [], i.e. 1st edge pairs touch
            #
            if w1.isClosed() and w2.isClosed() and len(faces_list) > 1 and faces_list[0]:
                faces_list[0].extend(
                    faces
                )  # TODO: To be reviewed, 'afterthought' on 2025.3.29, seems by 'extend', faces in 1st and last faces are not in sequential order
            else:
                faces_list.append(faces)  # Break into separate list
        from collections import Counter

        if faces_list:
            faces_fused_list = []
            for faces in faces_list:
                dir = []
                countDir = None
                for f in faces:
                    dir.append(f.normalAt(0, 0).z)
                countDir = Counter(dir)
                l = len(faces)
                m = max(countDir.values())  # max(countDir, key=countDir.get)
                if m != l:
                    print(
                        "DraftGeomUtils: Problem, the direction of "
                        + str(l - m)
                        + " out of "
                        + str(l)
                        + " segment is reversed, please check!"
                    )
                if len(faces) > 1:
                    # Below not good if a face is self-intersecting or reversed
                    # faces_fused = faces[0].fuse(faces[1:]).removeSplitter().Faces[0]
                    rf = faces[0]
                    for f in faces[1:]:
                        rf = rf.fuse(f).removeSplitter().Faces[0]
                        # rf = rf.fuse(f)  # Not working
                    # rf = rf.removeSplitter().Faces[0]  # Not working
                    faces_fused_list.append(rf)
                # faces might be empty list [], see above; skip if empty
                elif faces:
                    faces_fused_list.append(faces[0])  # Only 1 face

            return Part.Compound(faces_fused_list)
        else:
            dir = []
            countDir = None
            for f in faces:
                dir.append(f.normalAt(0, 0).z)
            countDir = Counter(dir)
            l = len(faces)
            m = max(countDir.values())  # max(countDir, key=countDir.get)
            if m != l:
                print(
                    "DraftGeomUtils: Problem, the direction of "
                    + str(l - m)
                    + " out of "
                    + str(l)
                    + " segment is reversed, please check!"
                )
            # Below not good if a face is self-intersecting or reversed
            # return faces[0].fuse(faces[1:]).removeSplitter().Faces[0]
            rf = faces[0]
            for f in faces[1:]:
                rf = rf.fuse(f).removeSplitter().Faces[0]
                # rf = rf.fuse(f)  # Not working
            # rf = rf.removeSplitter().Faces[0]  # Not working
            return rf

    elif w1.isClosed() and w2.isClosed():
        d1 = w1.BoundBox.DiagonalLength
        d2 = w2.BoundBox.DiagonalLength
        if d1 < d2:
            w1, w2 = w2, w1
        # return Part.Face(w1).cut(Part.Face(w2)).Faces[0] # Only works if wires do not self-intersect.
        try:
            face = Part.Face([w1, w2])
            face.fix(1e-7, 0, 1)
            return face
        except Part.OCCError:
            print("DraftGeomUtils: unable to bind wires")
            return None
    else:
        return create_face(w1, w2)


def cleanFaces(shape):
    """Remove inner edges from coplanar faces."""
    faceset = shape.Faces

    def find(hc):
        """Find a face with the given hashcode."""
        for f in faceset:
            if f.hashCode() == hc:
                return f

    def findNeighbour(hface, hfacelist):
        """Find the first neighbour of a face, and return its index."""
        eset = []
        for e in find(hface).Edges:
            eset.append(e.hashCode())
        for i in range(len(hfacelist)):
            for ee in find(hfacelist[i]).Edges:
                if ee.hashCode() in eset:
                    return i
        return None

    # build lookup table
    lut = {}
    for face in faceset:
        for edge in face.Edges:
            if edge.hashCode() in lut:
                lut[edge.hashCode()].append(face.hashCode())
            else:
                lut[edge.hashCode()] = [face.hashCode()]

    # print("lut:",lut)
    # take edges shared by 2 faces
    sharedhedges = []
    for k, v in lut.items():
        if len(v) == 2:
            sharedhedges.append(k)

    # print(len(sharedhedges)," shared edges:",sharedhedges)
    # find those with same normals
    targethedges = []
    for hedge in sharedhedges:
        faces = lut[hedge]
        n1 = find(faces[0]).normalAt(0.5, 0.5)
        n2 = find(faces[1]).normalAt(0.5, 0.5)
        if n1 == n2:
            targethedges.append(hedge)

    # print(len(targethedges)," target edges:",targethedges)
    # get target faces
    hfaces = []
    for hedge in targethedges:
        for f in lut[hedge]:
            if f not in hfaces:
                hfaces.append(f)

    # print(len(hfaces)," target faces:",hfaces)
    # sort islands
    islands = [[hfaces.pop(0)]]
    currentisle = 0
    currentface = 0
    found = True
    while hfaces:
        if not found:
            if len(islands[currentisle]) > (currentface + 1):
                currentface += 1
                found = True
            else:
                islands.append([hfaces.pop(0)])
                currentisle += 1
                currentface = 0
                found = True
        else:
            f = findNeighbour(islands[currentisle][currentface], hfaces)
            if f is not None:
                islands[currentisle].append(hfaces.pop(f))
            else:
                found = False

    # print(len(islands)," islands:",islands)
    # make new faces from islands
    newfaces = []
    treated = []
    for isle in islands:
        treated.extend(isle)
        fset = []
        for i in isle:
            fset.append(find(i))
        bounds = getBoundary(fset)
        shp = Part.Wire(Part.__sortEdges__(bounds))
        shp = Part.Face(shp)
        if shp.normalAt(0.5, 0.5) != find(isle[0]).normalAt(0.5, 0.5):
            shp.reverse()
        newfaces.append(shp)

    # print("new faces:",newfaces)
    # add remaining faces
    for f in faceset:
        if not f.hashCode() in treated:
            newfaces.append(f)

    # print("final faces")
    # finishing
    fshape = Part.makeShell(newfaces)
    if shape.isClosed():
        fshape = Part.makeSolid(fshape)
    return fshape


def removeSplitter(shape):
    """Return a face from removing the splitter in a list of faces.

    This is an alternative, shared edge-based version of Part.removeSplitter.
    Returns a face, or `None` if the operation failed.
    """
    lookup = dict()
    for f in shape.Faces:
        for e in f.Edges:
            h = e.hashCode()
            if h in lookup:
                lookup[h].append(e)
            else:
                lookup[h] = [e]

    edges = [e[0] for e in lookup.values() if len(e) == 1]

    try:
        face = Part.Face(Part.Wire(edges))
    except Part.OCCError:
        # operation failed
        return None
    else:
        if face.isValid():
            return face

    return None


## @}