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Correct surface triangulation algorithms

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This commit is contained in:
Guille 2020-12-21 09:42:54 -05:00
parent b0ca46332c
commit 4c7eea5524
3 changed files with 101 additions and 49 deletions
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76
city_model_structure/attributes/polyhedron.py
View File

@ -69,6 +69,46 @@ class Polyhedron:
for point in surface.points:
print(point[0] - self.min_x, point[1] - self.min_y, point[2] - self.min_z)
@staticmethod
def _get_regions(point_index, points_list):
if point_index == 0:
# first point in the polygon so the triangle is the points n-1, n, 0
triangle_left = ' '.join(str(e) for e in [*points_list[len(points_list) - 6:], *points_list[0:3]])
# remove point n
rest_points_left = ' '.join(str(e) for e in [*points_list[:len(points_list) - 3]])
elif point_index == 3:
# second point in the polygon so the triangle is the points n, 0, 1
triangle_left = ' '.join(str(e) for e in [*points_list[len(points_list) - 3:], *points_list[0:6]])
# remove point 0
rest_points_left = ' '.join(str(e) for e in [*points_list[3:]])
else:
# normal point index-2¸index-1, index
triangle_left = ' '.join(str(e) for e in [*points_list[point_index - 6:point_index + 3]])
# remove middle point (index - 1)
rest_points_left = ' '.join(str(e) for e in [*points_list[0:point_index - 3], *points_list[point_index:]])
if point_index < len(points_list) - 6:
# normal point index, index+1, index+2
triangle_right = ' '.join(str(e) for e in [*points_list[point_index:point_index + 9]])
rest_points_right = ' '.join(str(e) for e in [*points_list[0:point_index + 3], *points_list[point_index + 6:]])
elif point_index == (len(points_list) - 6):
# last two points in the polygon so the triangle is the points n-1, n, 0
triangle_right = ' '.join(str(e) for e in [*points_list[point_index:], *points_list[0:3]])
rest_points_right = ' '.join(str(e) for e in [*points_list[:len(points_list - 3)]])
else:
# last point in the polygon so the triangle is n, 0, 1
triangle_right = ' '.join(str(e) for e in [*points_list[len(points_list) - 3:], *points_list[0:6]])
rest_points_right = ' '.join(str(e) for e in [*points_list[3:]])
if len(triangle_right) < 3:
print(f'error right!!!! {triangle_right}')
if len(triangle_left) < 3:
print(f'error right!!!! {triangle_left}')
return (Surface(triangle_left, remove_last=False), Surface(rest_points_left, remove_last=False)), \
(Surface(triangle_right, remove_last=False), Surface(rest_points_right, remove_last=False))
def _print(self, surface):
for point in surface.points:
print(point[0]-surface.min_x, point[1]-surface.min_y, point[2]-surface.min_z)
def _triangulate(self, surface):
triangles = []
triangles_count = len(surface.points) - 2
@ -76,33 +116,43 @@ class Polyhedron:
point_index = 0
area = surface.area
while len(triangles) < triangles_count:
# select a triangle starting at point index
triangle_points = ' '.join(str(e) for e in [*points_list[point_index:point_index + 9]])
# remove the middle vertex from previous triangle
rest_points = ' '.join(str(e) for e in [*points_list[0:point_index+3], *points_list[point_index+6:]])
triangular_surface = Surface(triangle_points, remove_last=False)
rest_surface = Surface(rest_points, remove_last=False)
t_area = triangular_surface.area
if t_area == 0 and self._geometry.almost_same_area(area, (t_area + rest_surface.area)):
area = rest_surface.area
triangles.append(triangular_surface)
points_list = rest_surface.points_list
if len(rest_surface.points) == 3:
triangles.append(rest_surface)
# get triangles and regions in both direction to find ears
left_direction, right_direction = Polyhedron._get_regions(point_index, points_list)
# todo: use enum to describe triangle or rest instead 0 1
right_area = right_direction[0].area + right_direction[1].area
left_area = left_direction[0].area + left_direction[1].area
if self._geometry.almost_same_area(area, left_area):
area = left_direction[1].area
point_index = 0
triangles.append(left_direction[0])
points_list = left_direction[1].points_list
elif self._geometry.almost_same_area(area, right_area):
area = right_direction[1].area
point_index = 0
triangles.append(right_direction[0])
points_list = right_direction[1].points_list
else:
point_index = point_index + 3
if point_index > len(points_list):
raise Exception('not ear found!')
if len(points_list) == 9:
# the rest point's are already a triangle
triangles.append(Surface(points_list, remove_last=False))
return triangles
@property
def faces(self) -> [[int]]:
"""
Polyhedron faces
:return: [[int]]
"""
if self._faces is None:
self._faces = []
for surface in self._surfaces:
face = []
points = surface.points
if len(points) != 3:

34
city_model_structure/attributes/surface.py
View File

@ -198,19 +198,6 @@ class Surface:
self._ground_polygon = None
return self._ground_polygon
@property
def area_geoms_class(self):
"""
Surface area in square meters
:return: float
"""
if self._area is None:
try:
self._area = self.polygon.get_area()
except AttributeError:
self._area = 0
return self._area
@property
def area(self):
"""
@ -230,15 +217,14 @@ class Surface:
if alpha == 0:
print('Warning: the area of a line or point cannot be calculated. Area = 0')
return 0
points_2d = self.rotate_surface_to_horizontal(self)
polygon_2d = pn.Polygon(np.array(points_2d))
horizontal_points = self.rotate_surface_to_horizontal(self)
area = 0
for i in range(0, len(polygon_2d.points)-1):
point = polygon_2d.points[i]
next_point = polygon_2d.points[i+1]
for i in range(0, len(horizontal_points)-1):
point = horizontal_points[i]
next_point = horizontal_points[i+1]
area += (next_point[1] + point[1]) / 2 * (next_point[0] - point[0])
next_point = polygon_2d.points[0]
point = polygon_2d.points[len(polygon_2d.points)-1]
next_point = horizontal_points[0]
point = horizontal_points[len(horizontal_points)-1]
area += (next_point[1] + point[1]) / 2 * (next_point[0] - point[0])
self._area = abs(area)
return self._area
@ -247,14 +233,14 @@ class Surface:
def rotate_surface_to_horizontal(surface):
z_vector = [0, 0, 1]
normal_vector = surface.normal
points_2d = []
horizontal_points = []
x = normal_vector[0]
y = normal_vector[1]
if x == 0 and y == 0:
# Already horizontal
for point in surface.points:
points_2d.append([point[0], point[1], 0])
horizontal_points.append([point[0], point[1], 0])
else:
alpha = surface.angle_between_vectors(normal_vector, z_vector)
rotation_line = np.cross(normal_vector, z_vector)
@ -274,8 +260,8 @@ class Surface:
else:
for point in surface.points:
new_point = np.matmul(rotation_base_matrix, point)
points_2d.append(new_point)
return points_2d
horizontal_points.append(new_point)
return horizontal_points
@staticmethod
def angle_between_vectors(vec_1, vec_2):

40
factories/geometry_feeders/city_gml.py
View File

@ -68,6 +68,7 @@ class CityGml:
:return: City
"""
if self._city is None:
# todo: refactor this method to clearly choose the gml type
self._city = City(self._lower_corner, self._upper_corner, self._srs_name)
i = 0
for o in self._gml['CityModel']['cityObjectMember']:
@ -79,10 +80,11 @@ class CityGml:
surfaces = CityGml._lod1_solid(o)
elif 'lod1MultiSurface' in o['Building']:
lod += 1
surfaces = CityGml._lod1_multisurface(o)
surfaces = CityGml._lod1_multi_surface(o)
elif 'lod2MultiSurface' in o['Building']:
# todo: check if this is a real case or a miss-formed citygml
lod = 2
surfaces = surfaces + CityGml._lod2_multisurface(o)
surfaces = surfaces + CityGml._lod2_solid_multi_surface(o)
else:
for bound in o['Building']['boundedBy']:
surface_type = next(iter(bound))
@ -133,27 +135,41 @@ class CityGml:
return surfaces
@staticmethod
def _lod1_multisurface(o):
def _lod1_multi_surface(o):
surfaces = [Surface(s['Polygon']['exterior']['LinearRing']['posList'])
for s in o['Building']['lod1MultiSurface']['MultiSurface']['surfaceMember']]
return surfaces
@staticmethod
def _lod2_multisurface(o):
def _lod2_solid_multi_surface(o):
surfaces = [Surface(s['Polygon']['exterior']['LinearRing']['posList'])
for s in o['Building']['lod2MultiSurface']['MultiSurface']['surfaceMember']]
return surfaces
@staticmethod
def _lod2_composite_surface(s):
surfaces = [Surface(sm['Polygon']['exterior']['LinearRing']['posList'])
for sm in s['CompositeSurface']['surfaceMember']]
return surfaces
@staticmethod
def _lod2_multi_surface(s, surface_type):
# todo: this need to be changed into surface bounded?
try:
surfaces = [Surface(s['Polygon']['exterior']['LinearRing']['posList']['#text'],
surface_type=GeometryHelper.gml_surface_to_libs(surface_type))]
except TypeError:
surfaces = [Surface(s['Polygon']['exterior']['LinearRing']['posList'],
surface_type=GeometryHelper.gml_surface_to_libs(surface_type))]
return surfaces
@staticmethod
def _lod2(bound):
surfaces = []
for surface_type in iter(bound):
try:
surfaces = [Surface(s['Polygon']['exterior']['LinearRing']['posList']['#text'],
surface_type=GeometryHelper.gml_surface_to_libs(surface_type))
for s in bound[surface_type]['lod2MultiSurface']['MultiSurface']['surfaceMember']]
except TypeError:
surfaces = [Surface(s['Polygon']['exterior']['LinearRing']['posList'],
surface_type=GeometryHelper.gml_surface_to_libs(surface_type))
for s in bound[surface_type]['lod2MultiSurface']['MultiSurface']['surfaceMember']]
for s in bound[surface_type]['lod2MultiSurface']['MultiSurface']['surfaceMember']:
if 'CompositeSurface' in s:
surfaces = surfaces + CityGml._lod2_composite_surface(s)
else:
surfaces = surfaces + CityGml._lod2_multi_surface(s, surface_type)
return surfaces