...
return cls(P2[0] - P1[0], P2[1] - P1[1])
TypeError: 'Vector' object does not support indexing
我是pygame和python的新手。我一直在努力练习构建类和向量,努力奋斗。
这是我的班级文件
import math
class Vector(object):
#defaults are set at 0.0 for x and y
def __init__(self, x=0.0, y=0.0):
self.x = x
self.y = y
#allows us to return a string for print
def __str__(self):
return "(%s, %s)"%(self.x, self.y)
# from_points generates a vector between 2 pairs of (x,y) coordinates
@classmethod
def from_points(cls, P1, P2):
return cls(P2[0] - P1[0], P2[1] - P1[1])
#calculate magnitude(distance of the line from points a to points b
def get_magnitude(self):
return math.sqrt(self.x**2+self.y**2)
#normalizes the vector (divides it by a magnitude and finds the direction)
def normalize(self):
magnitude = self.get_magnitude()
self.x/= magnitude
self.y/= magnitude
#adds two vectors and returns the results(a new line from start of line ab to end of line bc)
def __add__(self, rhs):
return Vector(self.x +rhs.x, self.y+rhs.y)
#subtracts two vectors
def __sub__(self, rhs):
return Vector(self.x - rhs.x, self.y-rhs.y)
#negates or returns a vector back in the opposite direction
def __neg__(self):
return Vector(-self.x, -self.y)
#multiply the vector (scales its size) multiplying by negative reverses the direction
def __mul__(self, scalar):
return Vector(self.x*scalar, self.y*scalar)
#divides the vector (scales its size down)
def __div__(self, scalar):
return Vector(self.x/scalar, self.y/scalar)
#gives my vector class an ability to return a tuple
def tuple(self):
return (self.x, self.y)
这是我的程序代码
#The simple mouse move game by Ramon Cabral
#imports
import pygame, sys, Vector
from pygame.locals import *
from Vector import *
#game init
pygame.init()
#screen
screen = pygame.display.set_mode((800,600),0,32)
#images
mouse_file = 'mouse.png'
MOUSE = pygame.image.load(mouse_file).convert_alpha()
#variables
bgcolor = (255,255,255)
position = Vector(100.0,100.0)
heading = Vector()
#clock and speed
clock = pygame.time.Clock()
speed = 250.0
#main game function
while True:
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
if event.type == MOUSEBUTTONDOWN:
destination = pygame.mouse.get_pos()
heading = Vector.from_points(position, destination)
heading.normalize()
screen.fill(bgcolor)
screen.blit(MOUSE, position.tuple())
time_passed = clock.tick(30.)
time_passed_seconds = time_passed/1000.0
distance_moved = time_passed_seconds*speed
position += heading * distance_moved
pygame.display.update()
答案 0 :(得分:1)
应该是:
@classmethod
def from_points(cls, P1, P2):
return cls(P2.x - P1.x, P2.y - P1.y)
原因是因为您的课程没有__getitem__
方法,因此您无法索引:
P2[0] #not allowed since this calls `__getitem__` and your class doesn't define it.