class Mesh:
'''A polygonal mesh class. Contains a Python list of vertex tuples and
a positional list of faces that are themselves Python lists.
'''
def __init__(self):
self.__verts = list()
self.__faces = PositionalList()
self.__polygon_types = list(
) # RP: shape of polygon or the name of n-gon
self.__numberOfVertices = 0 # RP: total number of vertices
self.__totalPolygons = 0 # RP: total number of faces
self.__polygons = dict(
) # RP: count of each type of faces, 3 squares, 5 pentagons etc
self.__x_minimum = 0 # RP: minimum of x co-ordinates
self.__y_minimum = 0 # RP: minimum of y co-ordinates
self.__z_minimum = 0 # RP: minimum of z co-ordinates
self.__x_maximum = 0 # RP: maximim of x co-ordinates
self.__y_maximum = 0 # RP: maximim of y co-ordinates
self.__z_maximum = 0 # RP: maximim of z co-ordinates
def loadOBJ(self, f):
'''Loads data from an OBJ file and stores it in the __verts and __faces
data members. Also calculates the X,Y,Z bounds and the counts of
face's index sizes.
'''
with open(f, 'r') as infile:
text = infile.read()
lines = text.split('\n')
for line_number, line_value in enumerate(lines):
if line_value is not '':
elements = line_value.split()
if elements[0] == 'v':
self.__verts += [
(float(elements[1]), float(elements[2]),
float(elements[3]))
]
self.__numberOfVertices += 1
if elements[0] == 'f':
face = list()
for vertex_index in elements[1:]:
face.append(int(vertex_index))
self.__faces.add_last(
face) # RP: ist of vertex indexs, face
# RP: In len(face) if-statement, counting the number of each type of polygon, if len(face)=3 or
# RP: say triangle already exist, add one to it, else start count from 1
if len(face) in self.__polygon_types:
# RP: self.__polygons is the dictionary of total number of each polygons
self.__polygons[len(face)] += 1
else:
self.__polygon_types.append(len(face))
self.__polygons[len(face)] = 1
# RP: Adding all types of polygon all in the total polygons
self.__totalPolygons += 1
def get_stats(self):
'''Gets the stats of the Mesh data:
- the total number of vertices
- the total number of polygons
- the number of polygons of each number of sides
- the mininum and maximum X, Y, and Z coordinates for
the entire mesh
'''
# MVM: Hint for the total number of polys of each number of
# of sides, use a dictionary.
# RP: Made a list of x,y and z elements/coordinates, to get minimum and maximum of each co-ordinates individually
x_elements = list()
y_elements = list()
z_elements = list()
for vertex in self.__verts:
x_elements.append(vertex[0])
y_elements.append(vertex[1])
z_elements.append(vertex[2])
self.__x_minimum = min(x_elements)
self.__y_minimum = min(y_elements)
self.__z_minimum = min(z_elements)
self.__x_maximum = max(x_elements)
self.__y_maximum = max(y_elements)
self.__z_maximum = max(z_elements)
stats = {
"totalVertices": self.__numberOfVertices,
"totalPolygon": self.__totalPolygons,
"numberOfPolygons": self.__polygons,
"minimumXCoordinates": self.__x_minimum,
"minimumYCoordinates": self.__y_minimum,
"minimumZCoordinates": self.__z_minimum,
"maximumXCoordinates": self.__x_maximum,
"maximumYCoordinates": self.__y_maximum,
"maximumZCoordinates": self.__z_maximum
}
return stats
def writeVTK(self, outfile):
'''Writes a VTK legacy ASCII format file from data stored in __verts
and __faces.
'''
with open(outfile, 'w') as outfile:
# RP: First part of vtk file, uptil vertices
outfile.write('# vtk DataFile Version 3.0\n')
outfile.write('An object\n')
outfile.write('ASCII\n')
outfile.write('DATASET POLYDATA\n')
outfile.write('POINTS ' + str(self.__numberOfVertices) +
' float\n')
for vertex in self.__verts:
outfile.write(
str(vertex[0]) + ' ' + str(vertex[1]) + ' ' +
str(vertex[2]) + '\n')
outfile.write('\n')
# RP: As in the dictionary {key:value}, typeOfPolygon(tri/4/penta...gon) is the key and numberOfThosePolygon
# is the value, which together is used to calculate total points for vtk file.
total_points = 0
for typeOfPolygon, numberOfThosePolygon in self.__polygons.items():
total_points += (typeOfPolygon + 1) * numberOfThosePolygon
outfile.write('POLYGONS ' + str(self.__totalPolygons) + ' ' +
str(total_points) + '\n')
for face in self.__faces:
outfile.write(str(len(face)) + ' ')
for vertex_index in face:
outfile.write(str(vertex_index - 1) + ' ')
outfile.write('\n')
def triangularize(self):
'''Triangularizes any non-triangles in the face list. It modifes
the list be replacing non-triangles with two or more triangles. The
modifcation occurs at the site of the non-triangle.'''
# RP: Because in Triangulation, we only need to print number of triangles
if 3 not in self.__polygon_types:
self.__polygons[3] = 0
self.__polygon_types.append(3)
pos = self.__faces.first(
) # RP: setting position of the first list in the PositionalList(self.__faces)
while pos is not None: # RP: will do one face at a time
face = pos.element(
) # RP: accessing the elements in that position of the list calling it face
if len(face) > 3:
for n in range(2,
len(face) -
1): # RP: if face is [1 2 3 4] say in square
triangle = list()
triangle.append(face[0]) # RP: here goes, face[0]=1
triangle.extend(
face[n:n + 2]
) # RP: here goes a slice of face[2:4], which is 3,4, and is
# extended to previous one, making it [1 3 4] face as triangle
self.__faces.add_before(
pos, triangle
) # RP: Now adding that face [1 3 4] before [1 2 3], similarly all the
# triangle face is added before the place where it is cut
self.__polygons[3] += 1
self.__totalPolygons += 1
self.__faces.replace(pos,
face[0:3]) # RP: Slice of face [1 2 3]
self.__polygons[3] += 1
pos = self.__faces.after(
pos) # RP: Giving the position to the next one
new_polygons = {3: self.__polygons[3]}
self.__polygons = new_polygons
def __repr__(self):
'''Print user-friendly representation of the Mesh object.'''
# MVM: have this call get_stats()
output = 'This is a 3D object which consists of {} type(s) of polygon(s).\n'.format(
len(self.__polygons))
output += 'Polygon stats:\n'
try:
output += '\tTotal Vertices:{0:>16}\n'.format(
self.get_stats()['totalVertices'])
output += '\tTotal Polygons:{0:>16}\n'.format(
self.get_stats()['totalPolygon'])
for key, values in self.get_stats()['numberOfPolygons'].items():
output += '\tTotal {0} sided polygon:{1:>9}\n'.format(
key, values)
output += '\tMinimum x coordinate:{0:>10.2f}\n'.format(
self.get_stats()['minimumXCoordinates'])
output += '\tMaximum x coordinate:{0:>10.2f}\n'.format(
self.get_stats()['maximumXCoordinates'])
output += '\tMinimum y coordinate:{0:>10.2f}\n'.format(
self.get_stats()['minimumYCoordinates'])
output += '\tMaximum y coordinate:{0:>10.2f}\n'.format(
self.get_stats()['maximumYCoordinates'])
output += '\tMinimum z coordinate:{0:>10.2f}\n'.format(
self.get_stats()['minimumZCoordinates'])
output += '\tMaximum z coordinate:{0:>10.2f}\n'.format(
self.get_stats()['maximumZCoordinates'])
except:
output += 'NO DATA\n'
return output
