user: Python code for a game of pong

assistant: Sure, here is a simple game of Pong in Python using the Pygame library:

```py
import random
import pygame, sys
from pygame.locals import *

pygame.init()
fps = pygame.time.Clock()

# colors
WHITE = (255, 255, 255)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLACK = (0, 0, 0)

# globals
WIDTH = 600
HEIGHT = 400
BALL_RADIUS = 20
PAD_WIDTH = 8
PAD_HEIGHT = 80
HALF_PAD_WIDTH = PAD_WIDTH / 2
HALF_PAD_HEIGHT = PAD_HEIGHT / 2
ball_pos = [0, 0]
ball_vel = [0, 0]
paddle1_vel = 0
paddle2_vel = 0
l_score = 0
r_score = 0

# canvas declaration
window = pygame.display.set_mode((WIDTH, HEIGHT), 0, 32)
pygame.display.set_caption("Hello World")

# helper function that spawns a ball, returns a position vector and a velocity vector
# if right is True, spawn to the right, else spawn to the left
def ball_init(right):
    global ball_pos, ball_vel  # these are vectors stored as lists
    ball_pos = [WIDTH / 2, HEIGHT / 2]
    horz = random.randrange(2, 4)
    vert = random.randrange(1, 3)

    if right == False:
        horz = -horz

    ball_vel = [horz, -vert]


# define event handlers
def init():
    global paddle1_pos, paddle2_pos, paddle1_vel, paddle2_vel, l_score, r_score  # these are floats
    global score1, score2  # these are ints
    paddle1_pos = [HALF_PAD_WIDTH - 1, HEIGHT / 2]
    paddle2_pos = [WIDTH + 1 - HALF_PAD_WIDTH, HEIGHT / 2]
    l_score = 0
    r_score = 0
    if random.randrange(0, 2) == 0:
        ball_init(True)
    else:
        ball_init(False)


# draw function of canvas
def draw(canvas):
    global paddle1_pos, paddle2_pos, ball_pos, ball_vel, l_score, r_score

    canvas.fill(BLACK)
    pygame.draw.line(canvas, WHITE, [WIDTH / 2, 0], [WIDTH / 2, HEIGHT], 1)
    pygame.draw.line(canvas, WHITE, [PAD_WIDTH, 0], [PAD_WIDTH, HEIGHT], 1)
    pygame.draw.line(
        canvas, WHITE, [WIDTH - PAD_WIDTH, 0], [WIDTH - PAD_WIDTH, HEIGHT], 1
    )
    pygame.draw.circle(canvas, WHITE, [WIDTH // 2, HEIGHT // 2], 70, 1)

    # update paddle's vertical position, keep paddle on the screen
    if paddle1_pos[1] > HALF_PAD_HEIGHT and paddle1_pos[1] < HEIGHT - HALF_PAD_HEIGHT:
        paddle1_pos[1] += paddle1_vel
    elif paddle1_pos[1] == HALF_PAD_HEIGHT and paddle1_vel > 0:
        paddle1_pos[1] += paddle1_vel
    elif paddle1_pos[1] == HEIGHT - HALF_PAD_HEIGHT and paddle1_vel < 0:
        paddle1_pos[1] += paddle1_vel

    if paddle2_pos[1] > HALF_PAD_HEIGHT and paddle2_pos[1] < HEIGHT - HALF_PAD_HEIGHT:
        paddle2_pos[1] += paddle2_vel
    elif paddle2_pos[1] == HALF_PAD_HEIGHT and paddle2_vel > 0:
        paddle2_pos[1] += paddle2_vel
    elif paddle2_pos[1] == HEIGHT - HALF_PAD_HEIGHT and paddle2_vel < 0:
        paddle2_pos[1] += paddle2_vel

    # update ball
    ball_pos[0] += int(ball_vel[0])
    ball_pos[1] += int(ball_vel[1])

    # draw paddles and ball
    pygame.draw.circle(canvas, RED, ball_pos, 20, 0)
    pygame.draw.polygon(
        canvas,
        GREEN,
        [
            [paddle1_pos[0] - HALF_PAD_WIDTH, paddle1_pos[1] - HALF_PAD_HEIGHT],
            [paddle1_pos[0] - HALF_PAD_WIDTH, paddle1_pos[1] + HALF_PAD_HEIGHT],
            [paddle1_pos[0] + HALF_PAD_WIDTH, paddle1_pos[1] + HALF_PAD_HEIGHT],
            [paddle1_pos[0] + HALF_PAD_WIDTH, paddle1_pos[1] - HALF_PAD_HEIGHT],
        ],
        0,
    )
    pygame.draw.polygon(
        canvas,
        GREEN,
        [
            [paddle2_pos[0] - HALF_PAD_WIDTH, paddle2_pos[1] - HALF_PAD_HEIGHT],
            [paddle2_pos[0] - HALF_PAD_WIDTH, paddle2_pos[1] + HALF_PAD_HEIGHT],
            [paddle2_pos[0] + HALF_PAD_WIDTH, paddle2_pos[1] + HALF_PAD_HEIGHT],
            [paddle2_pos[0] + HALF_PAD_WIDTH, paddle2_pos[1] - HALF_PAD_HEIGHT],
        ],
        0,
    )

    # ball collision check on top and bottom walls
    if int(ball_pos[1]) <= BALL_RADIUS:
        ball_vel[1] = -ball_vel[1]
    if int(ball_pos[1]) >= HEIGHT + 1 - BALL_RADIUS:
        ball_vel[1] = -ball_vel[1]

    # ball collison check on gutters or paddles
    if int(ball_pos[0]) <= BALL_RADIUS + PAD_WIDTH and int(ball_pos[1]) in range(
        paddle1_pos[1] - HALF_PAD_HEIGHT, paddle1_pos[1] + HALF_PAD_HEIGHT, 1
    ):
        ball_vel[0] = -ball_vel[0]
        ball_vel[0] *= 1.1
        ball_vel[1] *= 1.1
    elif int(ball_pos[0]) <= BALL_RADIUS + PAD_WIDTH:
        r_score += 1
        ball_init(True)

    if int(ball_pos[0]) >= WIDTH + 1 - BALL_RADIUS - PAD_WIDTH and int(
        ball_pos[1]
    ) in range(paddle2_pos[1] - HALF_PAD_HEIGHT, paddle2_pos[1] + HALF_PAD_HEIGHT, 1):
        ball_vel[0] = -ball_vel[0]
        ball_vel[0] *= 1.1
        ball_vel[1] *= 1.1
    elif int(ball_pos[0]) >= WIDTH + 1 - BALL_RADIUS - PAD_WIDTH:
        l_score += 1
        ball_init(False)

    # update scores
    myfont1 = pygame.font.SysFont("Comic Sans MS", 20)
    label1 = myfont1.render("Score " + str(l_score), 1, (255, 255, 0))
    canvas.blit(label1, (50, 20))

    myfont2 = pygame.font.SysFont("Comic Sans MS", 20)
    label2 = myfont2.render("Score " + str(r_score), 1, (255, 255, 0))
    canvas.blit(label2, (470, 20))


# keydown handler
def keydown(event):
    global paddle1_vel, paddle2_vel

    if event.key == K_UP:
        paddle2_vel = -8
    elif event.key == K_DOWN:
        paddle2_vel = 8
    elif event.key == K_w:
        paddle1_vel = -8
    elif event.key == K_s:
        paddle1_vel = 8


# keyup handler
def keyup(event):
    global paddle1_vel, paddle2_vel

    if event.key in (K_w, K_s):
        paddle1_vel = 0
    elif event.key in (K_UP, K_DOWN):
        paddle2_vel = 0


init()


# game loop
while True:

    draw(window)

    for event in pygame.event.get():

        if event.type == KEYDOWN:
            keydown(event)
        elif event.type == KEYUP:
            keyup(event)
        elif event.type == QUIT:
            pygame.quit()
            sys.exit()

    pygame.display.update()
    fps.tick(60)
```

user: Thanks! But that code dosen't work. A window opens, but then suddently closess with the following error:
```
Traceback (most recent call last):
pong.py", line 184, in <module>
    draw(window)
pong.py", line 124, in draw
    if int(ball_pos[0]) <= BALL_RADIUS + PAD_WIDTH and int(ball_pos[1]) in range(
TypeError: 'float' object cannot be interpreted as an integer
```

assistant: The error statement: 
```
TypeError: 'float' object cannot be interpreted as an integer
```
indicates that there is a function that requires an integer argument which is receiving a float primitive instead as an argument.  Line 124 and line 136 are responsible for checking collision between the gutters and the balls, and both must be fixed.  The root cause appears to be that the calculation on line 20 and 21, for HALF_PAD_WIDTH and HALF_PAD_HEIGHT were calculated at the top of the program using the float division operator (/) and not the python integer division operator (//).  However, it is sometimes easier to just cast your arguments to your function to integers, as long as you know this is the intended behavior for your program.  Because the python "range" function requires an integer arguments for start and stop positions, each input argument to the python range function on line 124 and 136 were cast to integers to solve the TypeError.

Following is the corrected python script to play pong:
```
import random
import pygame, sys
from pygame.locals import *

pygame.init()
fps = pygame.time.Clock()

# colors
WHITE = (255, 255, 255)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLACK = (0, 0, 0)

# globals
WIDTH = 600
HEIGHT = 400
BALL_RADIUS = 20
PAD_WIDTH = 8
PAD_HEIGHT = 80
HALF_PAD_WIDTH = PAD_WIDTH / 2
HALF_PAD_HEIGHT = PAD_HEIGHT / 2
ball_pos = [0, 0]
ball_vel = [0, 0]
paddle1_vel = 0
paddle2_vel = 0
l_score = 0
r_score = 0

# canvas declaration
window = pygame.display.set_mode((WIDTH, HEIGHT), 0, 32)
pygame.display.set_caption("Hello World")

# helper function that spawns a ball, returns a position vector and a velocity vector
# if right is True, spawn to the right, else spawn to the left
def ball_init(right):
    global ball_pos, ball_vel  # these are vectors stored as lists
    ball_pos = [WIDTH / 2, HEIGHT / 2]
    horz = random.randrange(2, 4)
    vert = random.randrange(1, 3)

    if right == False:
        horz = -horz

    ball_vel = [horz, -vert]


# define event handlers
def init():
    global paddle1_pos, paddle2_pos, paddle1_vel, paddle2_vel, l_score, r_score  # these are floats
    global score1, score2  # these are ints
    paddle1_pos = [HALF_PAD_WIDTH - 1, HEIGHT / 2]
    paddle2_pos = [WIDTH + 1 - HALF_PAD_WIDTH, HEIGHT / 2]
    l_score = 0
    r_score = 0
    if random.randrange(0, 2) == 0:
        ball_init(True)
    else:
        ball_init(False)


# draw function of canvas
def draw(canvas):
    global paddle1_pos, paddle2_pos, ball_pos, ball_vel, l_score, r_score

    canvas.fill(BLACK)
    pygame.draw.line(canvas, WHITE, [WIDTH / 2, 0], [WIDTH / 2, HEIGHT], 1)
    pygame.draw.line(canvas, WHITE, [PAD_WIDTH, 0], [PAD_WIDTH, HEIGHT], 1)
    pygame.draw.line(
        canvas, WHITE, [WIDTH - PAD_WIDTH, 0], [WIDTH - PAD_WIDTH, HEIGHT], 1
    )
    pygame.draw.circle(canvas, WHITE, [WIDTH // 2, HEIGHT // 2], 70, 1)

    # update paddle's vertical position, keep paddle on the screen
    if paddle1_pos[1] > HALF_PAD_HEIGHT and paddle1_pos[1] < HEIGHT - HALF_PAD_HEIGHT:
        paddle1_pos[1] += paddle1_vel
    elif paddle1_pos[1] == HALF_PAD_HEIGHT and paddle1_vel > 0:
        paddle1_pos[1] += paddle1_vel
    elif paddle1_pos[1] == HEIGHT - HALF_PAD_HEIGHT and paddle1_vel < 0:
        paddle1_pos[1] += paddle1_vel

    if paddle2_pos[1] > HALF_PAD_HEIGHT and paddle2_pos[1] < HEIGHT - HALF_PAD_HEIGHT:
        paddle2_pos[1] += paddle2_vel
    elif paddle2_pos[1] == HALF_PAD_HEIGHT and paddle2_vel > 0:
        paddle2_pos[1] += paddle2_vel
    elif paddle2_pos[1] == HEIGHT - HALF_PAD_HEIGHT and paddle2_vel < 0:
        paddle2_pos[1] += paddle2_vel

    # update ball
    ball_pos[0] += int(ball_vel[0])
    ball_pos[1] += int(ball_vel[1])

    # draw paddles and ball
    pygame.draw.circle(canvas, RED, ball_pos, 20, 0)
    pygame.draw.polygon(
        canvas,
        GREEN,
        [
            [paddle1_pos[0] - HALF_PAD_WIDTH, paddle1_pos[1] - HALF_PAD_HEIGHT],
            [paddle1_pos[0] - HALF_PAD_WIDTH, paddle1_pos[1] + HALF_PAD_HEIGHT],
            [paddle1_pos[0] + HALF_PAD_WIDTH, paddle1_pos[1] + HALF_PAD_HEIGHT],
            [paddle1_pos[0] + HALF_PAD_WIDTH, paddle1_pos[1] - HALF_PAD_HEIGHT],
        ],
        0,
    )
    pygame.draw.polygon(
        canvas,
        GREEN,
        [
            [paddle2_pos[0] - HALF_PAD_WIDTH, paddle2_pos[1] - HALF_PAD_HEIGHT],
            [paddle2_pos[0] - HALF_PAD_WIDTH, paddle2_pos[1] + HALF_PAD_HEIGHT],
            [paddle2_pos[0] + HALF_PAD_WIDTH, paddle2_pos[1] + HALF_PAD_HEIGHT],
            [paddle2_pos[0] + HALF_PAD_WIDTH, paddle2_pos[1] - HALF_PAD_HEIGHT],
        ],
        0,
    )

    # ball collision check on top and bottom walls
    if int(ball_pos[1]) <= BALL_RADIUS:
        ball_vel[1] = -ball_vel[1]
    if int(ball_pos[1]) >= HEIGHT + 1 - BALL_RADIUS:
        ball_vel[1] = -ball_vel[1]

    # ball collison check on gutters or paddles
    if int(ball_pos[0]) <= BALL_RADIUS + PAD_WIDTH and int(ball_pos[1]) in range(
        int(paddle1_pos[1] - HALF_PAD_HEIGHT), int(paddle1_pos[1] + HALF_PAD_HEIGHT), 1
    ):
        ball_vel[0] = -ball_vel[0]
        ball_vel[0] *= 1.1
        ball_vel[1] *= 1.1
    elif int(ball_pos[0]) <= BALL_RADIUS + PAD_WIDTH:
        r_score += 1
        ball_init(True)

    if int(ball_pos[0]) >= WIDTH + 1 - BALL_RADIUS - PAD_WIDTH and int(
        ball_pos[1]
    ) in range(int(paddle2_pos[1] - HALF_PAD_HEIGHT), int(paddle2_pos[1] + HALF_PAD_HEIGHT), 1):
        ball_vel[0] = -ball_vel[0]
        ball_vel[0] *= 1.1
        ball_vel[1] *= 1.1
    elif int(ball_pos[0]) >= WIDTH + 1 - BALL_RADIUS - PAD_WIDTH:
        l_score += 1
        ball_init(False)

    # update scores
    myfont1 = pygame.font.SysFont("Comic Sans MS", 20)
    label1 = myfont1.render("Score " + str(l_score), 1, (255, 255, 0))
    canvas.blit(label1, (50, 20))

    myfont2 = pygame.font.SysFont("Comic Sans MS", 20)
    label2 = myfont2.render("Score " + str(r_score), 1, (255, 255, 0))
    canvas.blit(label2, (470, 20))


# keydown handler
def keydown(event):
    global paddle1_vel, paddle2_vel

    if event.key == K_UP:
        paddle2_vel = -8
    elif event.key == K_DOWN:
        paddle2_vel = 8
    elif event.key == K_w:
        paddle1_vel = -8
    elif event.key == K_s:
        paddle1_vel = 8


# keyup handler
def keyup(event):
    global paddle1_vel, paddle2_vel

    if event.key in (K_w, K_s):
        paddle1_vel = 0
    elif event.key in (K_UP, K_DOWN):
        paddle2_vel = 0


init()


# game loop
while True:

    draw(window)

    for event in pygame.event.get():

        if event.type == KEYDOWN:
            keydown(event)
        elif event.type == KEYUP:
            keyup(event)
        elif event.type == QUIT:
            pygame.quit()
            sys.exit()

    pygame.display.update()
    fps.tick(60)

```