I've been trying to code the Pong minigame using Turtle Graphics. Everything seems to work perfectly except for the beginning. I want the main loop to start iterating ONLY once the space key is pressed. Here is the part i've been having trouble with:
## Start the game
start = False
def start_game():
startmessage.clear() #This is a turtle i created to show the message "Press SPACE to start"
start = True
ball_start() #This is a function i created to get the ball moving
wn.onkeypress(start_game, "space")
## Main loop
while start == True:
I've included .listen() and .mainloop(), so that's not the problem. The full code is below. If i run the program with that code, this is what it does:
Here is the full code in case I'm missing something important:
import turtle
import random
import time
## Screen setup
wn = turtle.Screen()
wn.title("Pong!")
wn.bgcolor("black")
wn.setup(width = 900, height = 700)
wn.tracer(0)
# Border
collisions = 0
border = turtle.Turtle()
border.penup()
border.color("white")
border.setposition(-400,-300)
border.pendown()
for side in range(2):
border.forward(800)
border.left(90)
border.forward(600)
border.left(90)
border.hideturtle()
# Scores
scoreA = 0
scoreB = 0
score_marker = turtle.Turtle()
score_marker.shape("blank")
score_marker.color("yellow")
score_marker.speed(0)
score_marker.penup()
score_marker.setposition(0, 310)
score_marker.pendown()
score_marker.write("Player A : {} Player B: {}".format(scoreA,scoreB), align = "center", font = ("Courier", 20, "bold"))
# Select number of points
maxpoints = int(input("Enter max points: "))
print("The player who first gets to {} points wins the game!".format(maxpoints))
# Start message
startmessage = turtle.Turtle()
startmessage.speed(0)
startmessage.color("white")
startmessage.shape("blank")
startmessage.penup()
startmessage.setposition(0,75)
startmessage.pendown()
startmessage.write("Press SPACE to start", align = "center", font = ("Courier", 20, "bold"))
# End message
endmessage = turtle.Turtle()
endmessage.speed(0)
endmessage.color("green")
endmessage.shape("blank")
endmessage.penup()
endmessage.setposition(0,0)
endmessage.pendown()
## Paddles
paddleB_speed = 25
paddleA_speed = paddleB_speed
wn.listen()
# Paddle A
paddleA = turtle.Turtle()
paddleA.speed(0)
paddleA.shape("square")
paddleA.color("white")
paddleA.shapesize(3.2,0.7)
paddleA.penup()
paddleA.goto(-350,0)
# Paddle A movement
def a_up():
y = paddleA.ycor() + paddleA_speed
paddleA.sety(y)
def a_down():
y = paddleA.ycor() - paddleA_speed
paddleA.sety(y)
wn.onkeypress(a_up,"w")
wn.onkeypress(a_down,"s")
# Paddle B
paddleB = turtle.Turtle()
paddleB.speed(0)
paddleB.shape("square")
paddleB.color("white")
paddleB.shapesize(3.2,0.7)
paddleB.penup()
paddleB.goto(350,0)
# Paddle B movement
def b_up():
y = paddleB.ycor() + paddleB_speed
paddleB.sety(y)
def b_down():
y = paddleB.ycor() - paddleB_speed
paddleB.sety(y)
wn.onkeypress(b_up,"Up")
wn.onkeypress(b_down,"Down")
## Ball
ball = turtle.Turtle()
ball.speed(0)
ball.shape("circle")
ball.color("white")
ball.shapesize(0.5,0.5)
ball.penup()
ball.setposition(0,0)
ballspeed = 0.3
ballspeed_increase = 0.01
# Ball starting movement
def ball_start():
angle_ranges = list(range(30,60)) + list(range(120,150)) + list(range(210,240)) + list(range(300,330))
angle = random.choice(angle_ranges)
ball.setheading(angle)
ball_start()
## Exit the game
def exit_game():
wn.bye()
## Start the game
start = False
def start_game():
startmessage.clear()
start = True
ball_start()
wn.onkeypress(start_game, "space")
## Main loop
while start == True:
wn.update()
### MOVEMENT
## Ball movement
ball.forward(ballspeed)
### COLLISIONS
## Paddles and border
# Paddle A
if paddleA.ycor() > 268:
paddleA.sety(268)
if paddleA.ycor() < -268:
paddleA.sety(-268)
# Paddle B
if paddleB.ycor() > 268:
paddleB.sety(268)
if paddleB.ycor() < -268:
paddleB.sety(-268)
## Ball and paddles
if paddleA.distance(ball) <= 10:
collisions += 1
#direction = ball.heading()
#ball.setheading(180 - random.randint(0,30) - direction)
ball.setheading(random.randint(110,250) + 180)
ball.forward(ballspeed + ballspeed_increase)
if paddleB.distance(ball) <= 10:
collisions += 1
#direction = ball.heading()
#ball.setheading(180 - random.randint(0,30) - direction)
ball.setheading(random.randint(110,250))
ball.forward(ballspeed + ballspeed_increase)
## Ball and border
# Top and bottom borders
if ball.ycor() < - 296 or ball.ycor() > 296:
collisions += 1
direction = ball.heading()
ball.setheading(360 - direction)
ball.forward(ballspeed + ballspeed_increase)
# Left and right borders
if ball.xcor() < -396: #--> Player B wins the point
delay = 0.1
time.sleep(1)
collisions += 1
ball.setposition(0,0)
scoreB += 1
score_marker.clear()
score_marker.write("Player A : {} Player B: {}".format(scoreA,scoreB), align = "center", font = ("Courier", 20, "bold"))
ball_start()
if ball.xcor() > 396: #--> Player A wins the poin
delay = 0.1
time.sleep(1)
collisions += 1
ball.setposition(0,0)
scoreA += 1
score_marker.clear()
score_marker.write("Player A : {} Player B: {}".format(scoreA,scoreB), align = "center", font = ("Courier", 20, "bold"))
ball_start()
# End of the game
if scoreA == maxpoints or scoreB == maxpoints:
if scoreA == maxpoints:
print("Player A wins the game!")
endmessage.write("Player A wins the game!\nA scored {} points\nB scored {} points".format(scoreA,scoreB), align = "center", font = ("Courier", 18, "bold"))
time.sleep(1)
endmessage.penup()
endmessage.setposition(0,-100)
endmessage.pendown()
endmessage.color("red")
endmessage.write("Press ESC to exit game", align = "center", font = ("Courier", 14, "normal"))
wn.onkeypress(exit_game, "Escape")
break
if scoreB == maxpoints:
print("Player B wins the game!")
endmessage.write("Player B wins the game!\nA scored {} points\nB scored {} points".format(scoreA,scoreB), align = "center", font = ("Courier", 18, "bold"))
time.sleep(1)
endmessage.penup()
endmessage.setposition(0,-100)
endmessage.pendown()
endmessage.color("red")
endmessage.write("Press ESC to exit game", align = "center", font = ("Courier", 14, "normal"))
wn.onkeypress(exit_game, "Escape")
break
wn.mainloop()
This code looks like it resets start but it doesn't -- it sets a local start and ignores the global start:
start = False
def start_game():
startmessage.clear()
start = True
ball_start()
You need a global statement:
start = False
def start_game():
global start
startmessage.clear()
start = True
ball_start()
The above is necessary but not sufficient. The next problem is the way you use a top level while loop instead of a timer event. The way I'd expect this game to start up and run would be more like:
from turtle import Screen, Turtle
running = False
def start_game():
global running
start_message.clear()
running = True
ball_start()
def ball_start():
start_message.write("We've started the game!", align="center", font=("Courier", 20, "bold"))
# what really ball_start() really does replaces the above...
def move_one_step():
if running:
screen.update()
# ...
screen.ontimer(move_one_step, 100)
screen = Screen()
start_message = Turtle()
start_message.hideturtle()
start_message.penup()
start_message.sety(75)
start_message.write("Press SPACE to start", align="center", font=("Courier", 20, "bold"))
screen.onkeypress(start_game, 'space')
screen.listen()
move_one_step()
screen.mainloop()