python - 卡特彼勒项目混乱
问题描述
我在我的项目中遇到了一个问题,可以使用一些帮助来找出我做错了什么。
import random
# Define some colors
black = ( 0, 0, 0)
white = ( 255, 255, 255)
green = ( 0, 255, 0)
red = ( 255, 0, 0)
class caterpillar:
def __init__(self, x, y):
self.face_xcoord = x
self.face_ycoord = y
self.body = segment_queue()
t = random.randrange(0,2)
if t == 0:
self.travel_direction = 'left'
else:
self.travel_direction = 'right'
def display_caterpillar(self, screen):
self.draw_face(screen)
self.draw_body(screen)
def draw_face(self, screen):
x = self.face_xcoord
y = self.face_ycoord
pygame.draw.ellipse(screen,red,[x, y, 40, 45])
pygame.draw.ellipse(screen,black,[x+6, y+10, 10, 15])
pygame.draw.ellipse(screen,black,[x+24, y+10, 10, 15])
pygame.draw.line(screen,black, (x+11, y), (x+9, y-10), 3)
pygame.draw.line(screen,black, (x+24, y), (x+26, y-10), 3)
def draw_body(self, screen):
# traverse the segment queue
current_node = self.body.head
while current_node is not None:
current_node.draw_segment(screen)
current_node = current_node.next
####### you need to complete these two methods
def grow(self):
if self.body.length == 0:
if self.travel_direction == 'left':
self.body.addSegment(self.face_xcoord + 40, self.face_ycoord)
elif self.travel_direction == 'right':
self.body.addSegment(self.face_xcoord - 35, self.face_ycoord)
else:
self.body.addSegment(self.body.last, self.face_ycoord)
# if body is empty new segment should be placed relative to head
# else find x and y coordinates for current last body segment
# call addSegment() method on self.body with correct location parameters
def move(self):
return
# check the direction of movement
# move head forwards by 2
# move body parts forwards by 2
class segment_queue:
def __init__(self):
self.length = 0
self.head = None
self.last = None
def isEmpty(self):
return self.length == 0
####### you need to complete this method
def addSegment(self, x, y):
node = body_segment(x, y)
if self.length == 0:
self.head = self.last = node
else:
last = self.last
last.next = node
self.last = node
self.length = self.length + 1
# create a new body_segment node, with parameters x and y
# if segment queue is empty, the new node is both head and last
# else, find the last node and then append the new node to the end of the queue
# increment length of the segment queue
class body_segment:
def __init__(self, x, y):
self.xcoord = x
self.ycoord = y
self.next = None
def draw_segment(self, screen):
x = self.xcoord
y = self.ycoord
pygame.draw.ellipse(screen,green,[x, y, 35, 40])
pygame.draw.line(screen,black, (x+8, y+35), (x+8, y+45), 3)
pygame.draw.line(screen,black, (x+24, y+35), (x+24, y+45), 3)
下一个文件
import catclass
# Define some colors
black = ( 0, 0, 0)
white = ( 255, 255, 255)
green = ( 0, 255, 0)
red = ( 255, 0, 0)
lightblue = ( 0, 0, 255)
# Initialize pygame
pygame.init()
# Set the height and width of the screen
size=[1000,400]
screen=pygame.display.set_mode(size)
# Set title of screen
pygame.display.set_caption("Caterpillar")
# Function to draw background scene
def draw_background():
screen.fill(black)
pygame.draw.rect(screen,green,[0, 300, 1000, 100])
pygame.draw.rect(screen,lightblue,[0, 0, 1000, 300])
pygame.draw.ellipse(screen,white,[50, 80, 100, 60])
pygame.draw.ellipse(screen,white,[120, 60, 180, 80])
pygame.draw.ellipse(screen,white,[700, 80, 150, 60])
# Create a caterpillar at a particular location
mycaterpillar = catclass.caterpillar(500, 250)
# Loop until the user clicks the close button.
done=False
# Used to manage how fast the screen updates
clock=pygame.time.Clock()
######################################
# -------- Main Program Loop -----------
while done==False:
for event in pygame.event.get(): # User did something
if event.type == pygame.QUIT: # If user clicked close
done=True # Flag that we are done so we exit this loop
if event.type == pygame.KEYDOWN: # If user wants to perform an action
# Figure out which action to perform
if event.key == pygame.K_SPACE:
mycaterpillar.grow()
if event.key == pygame.K_m:
mycaterpillar.move()
# Draw the background scene
draw_background()
# Draw the caterpillar
mycaterpillar.display_caterpillar(screen)
# Limit to 20 frames per second
clock.tick(10)
# Go ahead and update the screen with what we've drawn.
pygame.display.flip()
# If you forget this line, the program will 'hang' on exit.
pygame.quit ()
我面临的问题是我无法弄清楚为什么我的毛毛虫在调用该grow()
方法时没有长出一个以上的身体部分。目前,只有一个段在调用if
语句中的函数时增长。该else
声明似乎没有做任何事情。
解决方案
我在您的代码中注意到的几件事:
- 在该
addSegment
方法中,length
从不超过零 - 在该
grow
方法中,仅添加第一段。其他段被忽略。 - 正如@Kingsley 提到的,您使用对象而不是 x 坐标创建一个新段
对类进行以下更改caterpillar
:
def grow(self):
if self.body.length == 0: # first segment
if self.travel_direction == 'left':
self.body.addSegment(self.face_xcoord + 40, self.face_ycoord)
elif self.travel_direction == 'right':
self.body.addSegment(self.face_xcoord - 35, self.face_ycoord)
else: # other segs
if self.travel_direction == 'left':
self.body.addSegment(self.body.last.xcoord + 40, self.face_ycoord)
elif self.travel_direction == 'right':
self.body.addSegment(self.body.last.xcoord - 35, self.face_ycoord)
def addSegment(self, x, y):
node = body_segment(x, y)
if self.length == 0:
self.head = self.last = node
self.length += 1 # add this line
else:
last = self.last
last.next = node
self.last = node
self.length = self.length + 1
输出
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