There are several ways to implement a timer in pygame. You can use the time that pygame.Clock.tick returns to increase or decrease a timer variable, calculate the time difference with pygame.time.get_ticks or use a custom event in conjunction with pygame.time.set_timer.
Example 1 - delta time:
import sys import random import pygame as pg class Block(pg.sprite.Sprite): def __init__(self, pos): super().__init__() self.image = pg.Surface((40, 40)) self.image.fill(pg.Color('sienna1')) self.rect = self.image.get_rect(topleft=pos) def main(): screen = pg.display.set_mode((640, 480)) clock = pg.time.Clock() font = pg.font.Font(None, 30) all_sprites = pg.sprite.Group() # Delta time is the time that has passed since clock.tick # was called the last time. dt = 0 # We'll subtract dt (delta time) from this timer variable. timer = 1 # 1 means one second. done = False while not done: for event in pg.event.get(): if event.type == pg.QUIT: done = True # Decrease timer to get a countdown. timer -= dt # When the timer is below or equal to 0, we spawn # a new block. if timer <= 0: all_sprites.add(Block((random.randrange(600), random.randrange(440)))) # Reset the countdown timer to one second. timer = 1 all_sprites.update() screen.fill(pg.Color('gray15')) all_sprites.draw(screen) timer_surface = font.render( str(round(timer, 3)), True, pg.Color('yellow')) screen.blit(timer_surface, (20, 20)) pg.display.flip() # dt = time in seconds that passed since last tick. # Divide by 1000 to convert milliseconds to seconds. dt = clock.tick(30) / 1000 if __name__ == '__main__': pg.init() main() pg.quit() sys.exit()
If you want to spawn exactly 1 sprite, you can add another variable like boss_spawned = False and change the timer only if the boss hasn't spawned:
if not boss_spawned: timer -= dt if timer <= 0: all_sprites.add(Block((random.randrange(600), random.randrange(440)))) boss_spawned = True
Or set the timer to exactly 0 after the spawn and only decrease the timer if it's != 0.
if timer != 0: timer -= dt if timer <= 0: all_sprites.add(Block((random.randrange(600), random.randrange(440)))) timer = 0
Example 2 - pygame.time.get_ticks (replace the main function above):
def main(): screen = pg.display.set_mode((640, 480)) clock = pg.time.Clock() font = pg.font.Font(None, 30) all_sprites = pg.sprite.Group() # Start time. now = pg.time.get_ticks() done = False while not done: for event in pg.event.get(): if event.type == pg.QUIT: done = True # If the time difference is greater than 1000 # milliseconds, spawn a block. time_difference = pg.time.get_ticks() - now if time_difference >= 1000: all_sprites.add(Block((random.randrange(600), random.randrange(440)))) # Reset the start time. now = pg.time.get_ticks() all_sprites.update() screen.fill(pg.Color('gray15')) all_sprites.draw(screen) timer_surface = font.render( str(time_difference/1000), True, pg.Color('yellow')) screen.blit(timer_surface, (20, 20)) pg.display.flip() clock.tick(30)
If you just want to count the kills or spawned mobs, you can increment a counter variable and then spawn the enemy boss when it exceeds some limit. The following example just counts the mouse clicks and spawns a block after 3 clicks.
def main(): screen = pg.display.set_mode((640, 480)) clock = pg.time.Clock() font = pg.font.Font(None, 30) all_sprites = pg.sprite.Group() # We'll just count mouse clicks in this example. # You can replace it with the kill count in your game. clicks = 0 done = False while not done: for event in pg.event.get(): if event.type == pg.QUIT: done = True if event.type == pg.MOUSEBUTTONDOWN: clicks += 1 if clicks >= 3: all_sprites.add(Block((random.randrange(600), random.randrange(440)))) clicks = 0 all_sprites.update() screen.fill(pg.Color('gray15')) all_sprites.draw(screen) clicks_surface = font.render(str(clicks), True, pg.Color('yellow')) screen.blit(clicks_surface, (20, 20)) pg.display.flip() clock.tick(30)
