Pygame - Unknown error in a multiplayer control function - python-3.x

Question

I am making a two player game in which two players can move simultaneously throughout.
The while loop goes like this:
while stop==0:
for event in pygame.event.get():
if event.type == pygame.QUIT:
stop = 1
#For player 1
#on pressing an arrow key
# xv, yv = velocity at which the object moves
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
xv = -1
elif event.key == pygame.K_RIGHT:
xv = 1
elif event.key == pygame.K_UP:
yv = -1
elif event.key == pygame.K_DOWN:
yv = 1
# on releasing an arrow key
elif event.type == pygame.KEYUP:
if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
xv = 0
elif event.key == pygame.K_UP or event.key == pygame.K_DOWN:
yv = 0
#For player 2
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_a:
xv2 = -1
elif event.key == pygame.K_d:
xv2 = 1
elif event.key == pygame.K_w:
yv2 = -1
elif event.key == pygame.K_s:
yv2 = 1
# on releasing an arrow key
elif event.type == pygame.KEYUP:
if event.key == pygame.K_a or event.key == pygame.K_d:
xv2 = 0
elif event.key == pygame.K_w or event.key == pygame.K_s:
yv2 = 0
Using the above code, only player 1 was able to move while player 2 remained still.
but after modifying the code like this it worked,
while stop==0:
for event in pygame.event.get():
if event.type == pygame.QUIT:
stop = 1
#For player 1
#on pressing an arrow key
# xv, yv = velocity at which the object moves
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
xv = -1
elif event.key == pygame.K_RIGHT:
xv = 1
elif event.key == pygame.K_UP:
yv = -1
elif event.key == pygame.K_DOWN:
yv = 1
# on releasing an arrow key
elif event.type == pygame.KEYUP:
if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
xv = 0
elif event.key == pygame.K_UP or event.key == pygame.K_DOWN:
yv = 0
#For player 2
if event.type == pygame.QUIT:
stop = 1
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_a:
xv2 = -1
elif event.key == pygame.K_d:
xv2 = 1
elif event.key == pygame.K_w:
yv2 = -1
elif event.key == pygame.K_s:
yv2 = 1
# on releasing an arrow key
elif event.type == pygame.KEYUP:
if event.key == pygame.K_a or event.key == pygame.K_d:
xv2 = 0
elif event.key == pygame.K_w or event.key == pygame.K_s:
yv2 = 0
The only change made was inserting
if event.type == pygame.QUIT:
stop = 1
before the elif statement of player 2. Can anyone help with this confusion?

Answer 1

You have
if event.type == pygame.QUIT:
elif event.type == pygame.KEYDOWN:
# player1
elif event.type == pygame.KEYUP:
elif event.type == pygame.KEYDOWN: # <-- this will never checked
# player2
Second pygame.KEYDOWN will be never use because first pygame.KEYDOWN catchs all KEYDOWN events.
You need only one pygame.KEYDOWN
if event.type == pygame.QUIT:
elif event.type == pygame.KEYDOWN:
# player1
# player2
elif event.type == pygame.KEYUP:
# player1
# player2
or you have to use two if
if event.type == pygame.QUIT:
elif event.type == pygame.KEYDOWN:
# player1
elif event.type == pygame.KEYUP:
# player1
if event.type == pygame.KEYDOWN:
# player2
elif event.type == pygame.KEYUP:
# player2
BTW. when you will use Classes then you will have two objects with own method to check events
if event.type == pygame.QUIT:
# quit
player1.handle_event(event)
player2.handle_event(event)
and every player will have own
def handle_event(self, event)
if event.type == pygame.KEYDOWN:
# do something
elif event.type == pygame.KEYUP:
# do something