Don't bother with threads. No need to make your live complicated.
Usually, you use a Clock anyway in your game (if not, you should start using it) to limit the framerate, and to ensure that your world moves at a constant rante (if not, you should start doing it).
So if you want to trigger something in, say, 5 seconds, just create a variable that holds the value 5000, and substract the time it took to process your last frame (which is returned by Clock.tick):
clock = pygame.time.Clock()
dt = 0
timer = 5000
while True:
...
timer -= dt
if timer <= 0:
do_something()
dt = clock.tick(60)
I hacked together a simple example below. There, I use a simple class that is also a Sprite to draw the remaining time to the screen. When the timer runs out, it calls a function that creates a new wave of zombies.
In the main loop, I check if there's no timer running and no zombies, and if that's the case, a new timer is created.
Here's the code:
import pygame
import pygame.freetype
import random
# a dict that defines the controls
# w moves up, s moves down etc
CONTROLS = {
pygame.K_w: ( 0, -1),
pygame.K_s: ( 0, 1),
pygame.K_a: (-1, 0),
pygame.K_d: ( 1, 0)
}
# a function that handles the behaviour a sprite that
# should be controled with the keys defined in CONTROLS
def keyboard_controlled_b(player, events, dt):
# let's see which keys are pressed, and create a
# movement vector from all pressed keys.
move = pygame.Vector2()
pressed = pygame.key.get_pressed()
for vec in (CONTROLS[k] for k in CONTROLS if pressed[k]):
move += vec
if move.length():
move.normalize_ip()
move *= (player.speed * dt/10)
# apply the movement vector to the position of the player sprite
player.pos += move
player.rect.center = player.pos
# a function that let's a sprite follow another one
# and kill it if they touch each other
def zombie_runs_to_target_b(target):
def zombie_b(zombie, events, dt):
if target.rect.colliderect(zombie.rect):
zombie.kill()
return
move = target.pos - zombie.pos
if move.length():
move.normalize_ip()
move *= (zombie.speed * dt/10)
zombie.pos += move
zombie.rect.center = zombie.pos
return zombie_b
# a simple generic sprite class that displays a simple, colored rect
# and invokes the given behaviour
class Actor(pygame.sprite.Sprite):
def __init__(self, color, pos, size, behavior, speed, *grps):
super().__init__(*grps)
self.image = pygame.Surface(size)
self.image.fill(color)
self.rect = self.image.get_rect(center=pos)
self.pos = pygame.Vector2(pos)
self.behavior = behavior
self.speed = speed
def update(self, events, dt):
self.behavior(self, events, dt)
# a sprite class that displays a timer
# when the timer runs out, a function is invoked
# and this sprite is killed
class WaveCounter(pygame.sprite.Sprite):
font = None
def __init__(self, time_until, action, *grps):
super().__init__(grps)
self.image = pygame.Surface((300, 50))
self.image.fill((3,2,1))
self.image.set_colorkey((3, 2, 1))
self.rect = self.image.get_rect(topleft=(10, 10))
if not WaveCounter.font:
WaveCounter.font = pygame.freetype.SysFont(None, 32)
WaveCounter.font.render_to(self.image, (0, 0), f'new wave in {time_until}', (255, 255, 255))
self.timer = time_until * 1000
self.action = action
def update(self, events, dt):
self.timer -= dt
self.image.fill((3,2,1))
WaveCounter.font.render_to(self.image, (0, 0), f'new wave in {int(self.timer / 1000) + 1}', (255, 255, 255))
if self.timer <= 0:
self.action()
self.kill()
def main():
pygame.init()
screen = pygame.display.set_mode((600, 480))
screen_rect = screen.get_rect()
clock = pygame.time.Clock()
dt = 0
sprites_grp = pygame.sprite.Group()
zombies_grp = pygame.sprite.Group()
wave_tm_grp = pygame.sprite.GroupSingle()
# the player is controlled with the keyboard
player = Actor(pygame.Color('dodgerblue'),
screen_rect.center,
(32, 32),
keyboard_controlled_b,
5,
sprites_grp)
# this function should be invoked once the timer runs out
def create_new_wave_func():
# let's create a bunch of zombies that follow the player
for _ in range(15):
x = random.randint(0, screen_rect.width)
y = random.randint(-100, 0)
Actor((random.randint(180, 255), 0, 0),
(x, y),
(26, 26),
zombie_runs_to_target_b(player),
random.randint(2, 4),
sprites_grp, zombies_grp)
while True:
events = pygame.event.get()
for e in events:
if e.type == pygame.QUIT:
return
# no timer, no zombies => create new timer
if len(wave_tm_grp) == 0 and len(zombies_grp) == 0:
WaveCounter(5, create_new_wave_func, sprites_grp, wave_tm_grp)
sprites_grp.update(events, dt)
screen.fill((80, 80, 80))
sprites_grp.draw(screen)
pygame.display.flip()
dt = clock.tick(60)
if __name__ == '__main__':
main()
