python-obja/obja.py

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#!/usr/bin/env python3
import sys
"""
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obja model for python.
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"""
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class Vector:
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"""
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The class that holds the x, y, and z coordinates of a vector.
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"""
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def __init__(self, x, y, z):
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"""
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Initializes a vector from values.
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"""
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self.x = x
self.y = y
self.z = z
def from_array(array):
"""
Creates a vector from an array of string representing floats.
"""
return Vector(0, 0, 0).set(array)
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def set(self, array):
"""
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Sets a vector from an array of string representing floats.
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"""
self.x = float(array[0])
self.y = float(array[1])
self.z = float(array[2])
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return self
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def translate(self, array):
"""
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Translates a vector from an array of string representing floats.
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"""
self.x += float(array[0])
self.y += float(array[1])
self.z += float(array[2])
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def __str__(self):
return "({}, {}, {})".format(self.x, self.y, self.z)
def __add__(self, other):
return Vector(self.x + other.x, self.y + other.y, self.z + other.z)
def __sub__(self, other):
return Vector(self.x - other.x, self.y - other.y, self.z - other.z)
def __mul__(self, other):
return Vector(self.x * other, self.y * other, self.z * other)
def __truediv__(self, other):
return Vector(self.x / other, self.y / other, self.z / other)
def __repr__(self):
return str(self)
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class Face:
"""
The class that holds a, b, and c, the indices of the vertices of the face.
"""
def __init__(self, array):
"""
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Initializes a face from an array of strings representing vector indices (starting at 1)
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"""
self.set(array)
self.visible = True
def set(self, array):
"""
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Sets a face from an array of strings representing vector indices (starting at 1)
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"""
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self.a = int(array[0].split('/')[0]) - 1
self.b = int(array[1].split('/')[0]) - 1
self.c = int(array[2].split('/')[0]) - 1
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return self
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def test(self, vertices, line = "unknown"):
"""
Tests if a face references only vertices that exist when the face is declared.
"""
if self.a >= len(vertices):
raise VertexError(self.a + 1, line)
if self.b >= len(vertices):
raise VertexError(self.b + 1, line)
if self.c >= len(vertices):
raise VertexError(self.c + 1, line)
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def __str__(self):
return "Face({}, {}, {})".format(self.a, self.b, self.c)
def __repr__(self):
return str(self)
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class VertexError(Exception):
"""
An operation references a vertex that does not exist.
"""
def __init__(self, index, line):
"""
Creates the error from index of the referenced vertex and the line where the error occured.
"""
self.line = line
self.index = index
super().__init__()
def __str__(self):
"""
Pretty prints the error.
"""
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return f'There is no vector {self.index} (line {self.line})'
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class FaceError(Exception):
"""
An operation references a face that does not exist.
"""
def __init__(self, index, line):
"""
Creates the error from index of the referenced face and the line where the error occured.
"""
self.line = line
self.index = index
super().__init__()
def __str__(self):
"""
Pretty prints the error.
"""
return f'There is no face {self.index} (line {self.line})'
class FaceVertexError(Exception):
"""
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An operation references a face vector that does not exist.
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"""
def __init__(self, index, line):
"""
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Creates the error from index of the referenced face vector and the line where the error occured.
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"""
self.line = line
self.index = index
super().__init__()
def __str__(self):
"""
Pretty prints the error.
"""
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return f'Face has no vector {self.index} (line {self.line})'
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class UnknownInstruction(Exception):
"""
An instruction is unknown.
"""
def __init__(self, instruction, line):
"""
Creates the error from instruction and the line where the error occured.
"""
self.line = line
self.instruction = instruction
super().__init__()
def __str__(self):
"""
Pretty prints the error.
"""
return f'Instruction {self.instruction} unknown (line {self.line})'
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class Model:
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"""
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The OBJA model.
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"""
def __init__(self):
"""
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Intializes an empty model.
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"""
self.vertices = []
self.faces = []
self.line = 0
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def get_vector_from_string(self, string):
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"""
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Gets a vector from a string representing the index of the vector, starting at 1.
To get the vector from its index, simply use model.vertices[i].
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"""
index = int(string) - 1
if index >= len(self.vertices):
raise FaceError(index + 1, self.line)
return self.vertices[index]
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def get_face_from_string(self, string):
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"""
Gets a face from a string representing the index of the face, starting at 1.
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To get the face from its index, simply use model.faces[i].
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"""
index = int(string) - 1
if index >= len(self.faces):
raise FaceError(index + 1, self.line)
return self.faces[index]
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def parse_file(self, path):
"""
Parses an OBJA file.
"""
with open(path, "r") as file:
for line in file.readlines():
self.parse_line(line)
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def parse_line(self, line):
"""
Parses a line of obja file.
"""
self.line += 1
split = line.split()
if len(split) == 0:
return
if split[0] == "v":
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self.vertices.append(Vector.from_array(split[1:]))
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elif split[0] == "ev":
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self.get_vector_from_string(split[1]).set(split[2:])
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elif split[0] == "tv":
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self.get_vector_from_string(split[1]).translate(split[2:])
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elif split[0] == "f" or split[0] == "tf":
for i in range(1, len(split) - 2):
face = Face(split[i:i+3])
face.test(self.vertices, self.line)
self.faces.append(face)
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elif split[0] == "ts":
for i in range(1, len(split) - 2):
if i % 2 == 1:
face = Face([split[i], split[i + 1], split[i + 2]])
else:
face = Face([split[i], split[i + 2], split[i + 1]])
face.test(self.vertices, self.line)
self.faces.append(face)
elif split[0] == "ef":
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self.get_face_from_string(split[1]).set(split[2:])
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elif split[0] == "efv":
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face = self.get_face_from_string(split[1])
vector = int(split[2])
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new_index = int(split[3]) - 1
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if vector == 1:
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face.a = new_index
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elif vector == 2:
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face.b = new_index
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elif vector == 3:
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face.c = new_index
else:
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raise FaceVertexError(vector, self.line)
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elif split[0] == "df":
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self.get_face_from_string(split[1]).visible = False
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elif split[0] == "#":
return
else:
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return
# raise UnknownInstruction(split[0], self.line)
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def parse_file(path):
"""
Parses a file and returns the model.
"""
model = Model()
model.parse_file(path)
return model
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def main():
if len(sys.argv) == 1:
print("obja needs a path to an obja file")
return
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model = parse_file(sys.argv[1])
print(model.vertices)
print(model.faces)
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if __name__ == "__main__":
main()