How to make the square change direction and move in the right direction when you press the "w,-CodePudding

How to make the square change direction and move in the right direction when you press the "w, a, s, d" buttons (So that he moves himself, after a single press of the button that sets the direction) Without using classes

from tkinter import *

root = Tk()
root.title('Snake')
root["width"] = 400
root["height"] = 400

field = Canvas(root)
rectangle = field.create_rectangle(10, 20, 30, 40)
field.grid(row=0, column=0)

def w(y):
    field.move(rectangle, 0, y)
    y  = 1
    root.after(5)

def s(y):
    field.move(rectangle, 0, y)
    y -= 1
    root.after(5)


def a(x):
    field.move(rectangle, x, 0)
    x -= 1
    root.after(5)

def d(x):
    field.move(rectangle, x, 0)
    x  = 10
    root.after(5)

x=0
y=0

def snake(event):
    if event.char == 'w':
        w(y)
    elif event.char == 'a':
        a(x)
    elif event.char == 's':
        s(y)
    elif event.char == 'd':
        d(x)
    field.move(rectangle, x, y)

root.bind("<Key>", snake)
root.mainloop()

CodePudding user response：

You need to declare two global variables for the x and y directions, for example dx and dy.

Then if you want the rectangle keep moving, you need to use .after() loop.

from tkinter import *

root = Tk()
root.title('Snake')
root["width"] = 400
root["height"] = 400

field = Canvas(root)
rectangle = field.create_rectangle(10, 20, 30, 40)
field.grid(row=0, column=0)

def move_snake():
    field.move(rectangle, dx, dy)
    # change the delay value 30 (ms) to other value to suit your case
    root.after(30, move_snake)

# initial directions for x and y
dx = 0
dy = 0

def change_direction(event):
    global dx, dy
    if event.char in 'wasd':
        dx = dy = 0
    if event.char == 'w':
        dy = -1    # move up
    elif event.char == 'a':
        dx = -1    # move left
    elif event.char == 's':
        dy = 1     # move down
    elif event.char == 'd':
        dx = 1     # move right

root.bind("<Key>", change_direction)
move_snake()  # start the moving loop
root.mainloop()

CodePudding user response：

Instead of incrementing and decrementing the x,y, have a default value, which you change as per the direction -

from tkinter import *

root = Tk()
root.title('Snake')
root["width"] = 400
root["height"] = 400

field = Canvas(root)
rectangle = field.create_rectangle(10, 20, 30, 40)
field.grid(row=0, column=0)

x = 0 # Default
y = 0
speed = 10 # Set your speed. The lesser the value, the more fast 

def pos(event):
    global x, y
    x = 0
    y = 0
    if event.char == 'w': 
        y = -1   # Changes the default values
    elif event.char == 'a':
        x = -1   
    elif event.char == 's':
        y = 1   
    elif event.char == 'd':
        x = 1

def snake():
    field.move(rectangle, x, y)
    root.after(speed, snake)

root.bind("<Key>", pos)
snake()
root.mainloop()