如何找到超过特定点或线的海龟？

Question

I want to write a turtle graphics program where, two turtles (I have named them 'tess' and 'alex') go forward on pressing specific keys ('t' for tess and 'a' for alex) and one turtle wins who passes a line that is set to (0, 350). That line itself is another turtle that forwards 400 towards east.

I have done pretty much of this, and wondering how to win a turtle that exceeds the line.

My segment of code is given below.

import turtle

t = turtle.Turtle()
wn = turtle.Screen()
wn.setup(400, 500)
wn.bgcolor("lightgreen")
wn.screensize(400, 500)
wn.setworldcoordinates(0, 0, 400, 500)
t.penup()
t.goto(0, 350)
t.pendown()
t.forward(400)

# tess
tess = turtle.Turtle()
tess.color("purple")
tess.penup()
tess.forward(100)
tess.pendown()
tess.left(90)
tess.forward(10)

# alex
alex = turtle.Turtle()
alex.color("blue")
alex.penup()
alex.forward(200)
alex.pendown()
alex.left(90)
alex.forward(10)

# making key handlers
def h1():
    tess.forward(50)


def h2():
    alex.forward(50)
#----------------------------

# wiring up keypresses to the handlers
wn.onkey(h1, 't')
wn.onkey(h2, 'a')


def handler_for_tess(x, y):
    wn.title("Tess clicked at {0}, {1}".format(x, y))
    #tess.left(90)
    tess.forward(50)


def handler_for_alex(x, y):
    wn.title("Alex clicked at {0}, {1}".format(x, y))
    #alex.right(84)
    alex.forward(50)


# listening mouse clicks
tess.onclick(handler_for_tess)
alex.onclick(handler_for_alex)

# listeing key press
wn.listen()

Answer 1

You just need to test the Y position of the turtles against the Y position of the finish line turtle. A starting example to the "winner" code:

# making key handlers
def h1():
    tess.forward(50)
    if tess.pos()[1] >= t.pos()[1]:
        wn.bgcolor("pink")

def h2():
    alex.forward(50)
    if alex.pos()[1] >= t.pos()[1]:
        wn.bgcolor("lightblue")

When a given turtle crosses the finish line the background will change to a lighter shade of the turtle itself (if you make "tess" red instead of purple...)

To finish this, you'd need to lock out the key handlers once one turtle has one and then bump the scores, etc. and restart the game.