蟒龜的邏輯錯誤

Question

我在Python 3.2龜編碼，我有這個美麗的坦克繪圖。我知道如何將它左移並書寫。但是，當試圖使坦克上下移動時。我面臨着它上升的問題，但如果我放開並再次按下向上按鈕。它轉向左邊。這可能很難解釋，所以我包含代碼。

""" 
Programmer: Bert 
Tank Run 1 
""" 

#------------------------------------------------------------------------------ 
#Importing random modules geddit 
from turtle import * 
from turtle import Turtle 
import turtle 
import random 

#Welcome Statement and story 
input("WELCOME TO TANK RUN 1!! PRESS ENTER TO CONTINUE") 
Name = input("Name your Tank: ") 
quitFunction = input(
"""The """ + Name + """ is in a battle and heading toward the 
enemy base camp so that the """ + Name + """ can blow it up 
Get to the base camp and do not let enemy 
artillery, or soldiers kill you. Good luck""" 
) 

#setting up variables 
unVar1 = 25 
unVar2 = 100 
unVar3 = 90 
unVar4 = 150 
unVar5 = -30 
unVar6 = 75 
unVar7 = 50 
t = Turtle() 

#defining shapes 
def polySquare(t, x, y, length): 
    t.goto(x, y) 
    t.setheading(270) 
    t.begin_poly() 
    for count in range(4): 
     t.forward(length) 
     t.left(90) 
    t.end_poly() 
    return t.get_poly() 

def polyCircle(t, x, y, radius): 
    t.up() 
    t.goto(x, y) 
    t.down() 
    t.hideturtle() 
    t.circle(radius) 
    t.end_poly() 
    return t.get_poly() 

def polyRectangle(t, x, y, length1, length2): 
    t.goto(x, y) 
    t.setheading(270) 
    t.begin_poly() 
    for count in range(2): 
     t.forward(length1) 
     t.left(90) 
     t.forward(length2) 
     t.left(90) 
    t.end_poly() 
    return t.get_poly() 

def drawLine(t, x1, x2, y1, y2): 
    t.up() 
    t.hideturtle() 
    t.goto(x1, y1) 
    t.do+wn() 
    t.goto(x2, y2) 

def tankCursor(): 
    """ 
    Create the tank cursor. An alternate solution is to toss the temporary turtle 
    and use the commented out polygon assignments instead of the poly* function calls 
    """ 
    temporary = turtle.Turtle() 
    screen = turtle.getscreen() 
    delay = screen.delay() 
    screen.delay(0) 
    temporary.hideturtle() 
    temporary.penup() 
    tank = turtle.Shape("compound") 
    # tire1 = ((10, unVar1), (10, unVar1 - unVar6), (10 + 30, unVar1 - unVar6), (10 + 30, unVar1)) 
    tire1 = polyRectangle(temporary, 10, unVar1, unVar6, 30) # Tire #1 
    tank.addcomponent(tire1, "gray", "black") 
    # tire2 = ((110, unVar1), (110, unVar1 - unVar6), (110 + 30, unVar1 - unVar6), (110 + 30, unVar1)) 
    tire2 = polyRectangle(temporary, 110, unVar1, unVar6, 30) # Tire #2 
    tank.addcomponent(tire2, "gray", "black") 
    # tire3 = ((110, unVar2), (110, unVar2 - unVar6), (110 + 30, unVar2 - unVar6), (110 + 30, unVar2)) 
    tire3 = polyRectangle(temporary, 110, unVar2, unVar6, 30) # Tire #3 
    tank.addcomponent(tire3, "gray", "black") 
    # tire4 = ((10, unVar2), (10, unVar2 - unVar6), (10 + 30, unVar2 - unVar6), (10 + 30, unVar2)) 
    tire4 = polyRectangle(temporary, 10, unVar2, unVar6, 30) # Tire #4 
    tank.addcomponent(tire4, "gray", "black") 
    # bodyTank = ((20, unVar3), (20, unVar3 - 130), (20 + 110, unVar3 - 130), (20 + 110, unVar3)) 
    bodyTank = polyRectangle(temporary, 20, unVar3, 130, 110) 
    tank.addcomponent(bodyTank, "black", "gray") 
    # gunTank = ((65, unVar4), (65, unVar4 - 100), (65 + 20, unVar4 - 100), (65 + 20, unVar4)) 
    gunTank = polyRectangle(temporary, 65, unVar4, 100, 20) # Gun 
    tank.addcomponent(gunTank, "black", "gray") 
    # exhaustTank = ((50, unVar5), (50, unVar5 - 20), (50 + 10, unVar5 - 20), (50 + 10, unVar5)) 
    exhaustTank = polyRectangle(temporary, 50, unVar5, 20, 10) 
    tank.addcomponent(exhaustTank, "black", "gray") 
    # turretTank = ((50, unVar7), (50, unVar7 - 50), (50 + 50, unVar7 - 50), (50 + 50, unVar7)) 
    turretTank = polySquare(temporary, 50, unVar7, 50) # Turret 
    tank.addcomponent(turretTank, "red", "gray") 
    turtle.addshape("tank", shape=tank) 
    del temporary 
    screen.delay(delay) 

tankCursor() # creates and registers the "tank" cursor shape 
tank = turtle 
tank.shape("tank") 

turtle.up() # get rid of the ink 
screen = turtle.Screen() 

def moveforward(): #I cannot get this function to work 
    tank.left(90) 
    tank.forward(40) 

def movebackward(): #I cannot get this function to work 
    tank.left(90) 
    tank.backward(40) 

def moveright(): 
    tank.forward(40) 

def moveleft(): 
    tank.backward(40) 

#Background color 
t.screen.bgcolor("green") 

#Movement of tank 
screen.onkeypress(moveright, "Right") 
screen.onkeypress(moveleft, "Left") 
screen.onkeypress(moveforward, "Up") 
screen.onkeypress(movebackward, "Down") 

Answer 1

繪製自定義光標時，除非您有理由不這樣做，否則請將光標設計置於原點（0，0）的中心位置。如果你畫出原點的一側，那麼當你的龜向右或向左轉時，它不會對稱。也就是說，當它向一個方向轉變時，它看起來很快，但是在相反的方向上，它似乎「走得很遠」。

我工作過坦克光標下面的多邊形，它的中心是炮塔的中心，並從繪圖例程中移除了setheading（）調用。

這個例子使用我認爲是一致的動作：不管坦克的方向如何，'向上'向前，'向下'向後，'向左'向左90度，'向右'向右90度。爲了演示這個動作，我也摘掉了這個例子：

import turtle 

# Defining shapes 
def polySquare(t, x, y, length): 
    t.goto(x, y) 
    t.begin_poly() 
    for count in range(4): 
     t.forward(length) 
     t.left(90) 
    t.end_poly() 
    return t.get_poly() 

def polyRectangle(t, x, y, length1, length2): 
    t.goto(x, y) 
    t.begin_poly() 
    for count in range(2): 
     t.forward(length1) 
     t.left(90) 
     t.forward(length2) 
     t.left(90) 
    t.end_poly() 
    return t.get_poly() 

def tankCursor(): 
    """ 
    Create the tank cursor. 
    """ 
    temporary = turtle.Turtle() 
    temporary.hideturtle() 
    temporary.penup() 

    screen = turtle.getscreen() 
    delay = screen.delay() 
    screen.delay(0) 

    tank = turtle.Shape("compound") 
    tire1 = polyRectangle(temporary, -65, -75, 30, 75) # Tire #1 
    tank.addcomponent(tire1, "gray", "black") 
    tire2 = polyRectangle(temporary, 35, -75, 30, 75) # Tire #2 
    tank.addcomponent(tire2, "gray", "black") 
    tire3 = polyRectangle(temporary, 35, 0, 30, 75) # Tire #3 
    tank.addcomponent(tire3, "gray", "black") 
    tire4 = polyRectangle(temporary, -65, 0, 30, 75) # Tire #4 
    tank.addcomponent(tire4, "gray", "black") 
    bodyTank = polyRectangle(temporary, -55, -65, 110, 130) 
    tank.addcomponent(bodyTank, "black", "gray") 
    gunTank = polyRectangle(temporary, -10, 25, 20, 100) # Gun 
    tank.addcomponent(gunTank, "black", "gray") 
    exhaustTank = polyRectangle(temporary, -25, -75, 10, 20) 
    tank.addcomponent(exhaustTank, "black", "gray") 
    turretTank = polySquare(temporary, -25, -25, 50) # Turret 
    tank.addcomponent(turretTank, "red", "gray") 
    turtle.addshape("tank", shape=tank) 

    del temporary 
    screen.delay(delay) 

tankCursor() # creates and registers the "tank" cursor shape 
turtle.shape("tank") 
turtle.up() # get rid of the ink 

# Movement of tank 
screen = turtle.Screen() 
screen.onkeypress(lambda : turtle.right(90), "Right") 
screen.onkeypress(lambda : turtle.left(90), "Left") 
screen.onkeypress(lambda : turtle.forward(40), "Up") 
screen.onkeypress(lambda : turtle.backward(40), "Down") 

turtle.listen() 

turtle.mainloop()