Python 通过 "not in" 列表进行海龟碰撞检测。为什么它不起作用？

Question

此测试代码的目标是让玩家使用 W、A、S、D 移动，并使用 ENTER 键开始或停止建造一堵墙。如果有人能告诉我为什么他只是偶尔撞到他的墙壁，我将不胜感激。也可以从一般意义上随意批评我的代码！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

如您问题的评论中所述，乌龟在浮点平面上徘徊，即使您认为它已返回到与之前完全相同的位置，该位置总会添加一点浮点噪声.将位置转换为 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稳健，因此看起来我们正在移动 1 而不是 10。它还尝试减少浮点到整数转换需要发生的位置数:

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 set 来包含墙壁。由于顺序无关紧要，这将使测试更快。

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