通过“不在”列表进行Python Turtle碰撞检测。 为什么不起作用？

Question

该测试代码的目标是使玩家随着W，A，S，D一起移动，并使用ENTER键开始或停止建造墙。 如果有人能告诉我为什么他有时只撞墙，我将不胜感激。 也可以随意批评我的代码！ 提前致谢。

import turtle

grid_size = 10

t1 = turtle.Pen()
t1.width(grid_size)
t1.up()

walls = [[0,0]]
walls.clear()

def toggle_building():
    if t1.isdown():
        t1.up()
    else:
        t1.down()

def lay_brick():
    if t1.isdown() and t1.pos() not in walls:
        walls.append(t1.pos())
    print("Brick layed.")

def print_pos():
    print(t1.pos())

def move_up():
    t1.setheading(90)
    if t1.pos() + [0, grid_size] not in walls:
        t1.forward(grid_size)
        lay_brick()
    else:
        print("wall")
    print_pos()
def move_left():
    t1.setheading(180)
    if t1.pos() - [grid_size, 0] not in walls:
        t1.forward(grid_size)
        lay_brick()
    else:
        print("wall")
    print_pos()
def move_down():
    t1.setheading(270)
    if t1.pos() - [0, grid_size] not in walls:
        t1.forward(grid_size)
        lay_brick()
    else:
        print("wall")
    print_pos()
def move_right():
    t1.setheading(0)
    if t1.pos() + [grid_size, 0] not in walls:
        t1.forward(grid_size)
        lay_brick()
    else:
        print("wall")
    print_pos()

turtle.onkeypress(move_up, "w")
turtle.onkeypress(move_left, "a")
turtle.onkeypress(move_down, "s")
turtle.onkeypress(move_right, "d")
turtle.onkeypress(toggle_building, "Return")
turtle.listen()

Answer 1

正如您对问题的评论所指出的那样，乌龟徘徊在浮点平面上，即使您认为它已经返回到与以前完全相同的位置，也始终会在该位置添加一点浮点噪声。 将头寸转换为int进行比较肯定有帮助，但可能还不够。

下面是我尝试通过更改坐标系本身来使其具有鲁棒性，从而使我们似乎移动的是1而不是10。它还尝试减少需要进行浮点到整数转换的位数：

from turtle import Screen, Turtle

GRID_SIZE = 10

def toggle_building():
    if turtle.isdown():
        turtle.penup()
    else:
        turtle.pendown()

def lay_brick(position):
    if turtle.isdown():
        walls.add(position)

def move_up():
    turtle.setheading(90)

    position = int(turtle.xcor()), int(turtle.ycor()) + 1

    if position not in walls:
        turtle.goto(position)
        lay_brick(position)

def move_left():
    turtle.setheading(180)

    position = int(turtle.xcor()) - 1, int(turtle.ycor())

    if position not in walls:
        turtle.goto(position)
        lay_brick(position)

def move_down():
    turtle.setheading(270)

    position = int(turtle.xcor()), int(turtle.ycor()) - 1

    if position not in walls:
        turtle.goto(position)
        lay_brick(position)

def move_right():
    turtle.setheading(0)

    position = int(turtle.xcor()) + 1, int(turtle.ycor())

    if position not in walls:
        turtle.goto(position)
        lay_brick(position)

screen = Screen()
WIDTH, HEIGHT = (screen.window_width() / 2) // GRID_SIZE, (screen.window_height() / 2) // GRID_SIZE
screen.setworldcoordinates(-WIDTH, -HEIGHT, WIDTH, HEIGHT)

turtle = Turtle()
turtle.width(GRID_SIZE)
turtle.fillcolor('red')
turtle.penup()

walls = set()

screen.onkeypress(move_up, "w")
screen.onkeypress(move_left, "a")
screen.onkeypress(move_down, "s")
screen.onkeypress(move_right, "d")
screen.onkeypress(toggle_building, "Return")

screen.listen()

screen.mainloop()

它还使用一set来容纳墙。 由于顺序无关紧要，因此可以使测试更快。