Event Timer Example

import pygame
from pygame.locals import *
import sys, os, traceback
if sys.platform in ["win32","win64"]: os.environ["SDL_VIDEO_CENTERED"]="1"
pygame.display.init()
pygame.font.init()

screen_size = [800,600]
icon = pygame.Surface((1,1)); icon.set_alpha(0); pygame.display.set_icon(icon)
pygame.display.set_caption("Event Timer Sample - Ian Mallett - 2018")
surface = pygame.display.set_mode(screen_size)

cooldown = 0.0

class Bullet(object):
    def __init__(self,x,y,t):
        self.x=x; self.y=y; self.t=t
bullets = []

def get_input():
    global cooldown
    keys_pressed = pygame.key.get_pressed()
    mouse_buttons = pygame.mouse.get_pressed()
    mouse_position = pygame.mouse.get_pos()
    mouse_rel = pygame.mouse.get_rel()
    for event in pygame.event.get():
        if   event.type == QUIT: return False
        elif event.type == KEYDOWN:
            if   event.key == K_ESCAPE: return False

    if keys_pressed[K_RETURN] and cooldown==0.0:
        cooldown = 0.2
        bullets.append(Bullet(400,300, 0))

    return True

def update(dt):
    global cooldown, bullets

    if cooldown > 0.0:
        cooldown -= dt
    else:
        cooldown = 0.0

    for bullet in bullets:
        bullet.x += 5
        bullet.t += dt

    bullets = [
        bullet for bullet in bullets if bullet.t<1.0
    ]

def draw():
    surface.fill((255,255,255))

    for bullet in bullets:
        pygame.draw.circle(surface,(255,0,0),(bullet.x,bullet.y),5,0)

    pygame.display.flip()

def main():
    clock = pygame.time.Clock()
    while True:
        if not get_input(): break
        update(1.0/60.0)
        draw()
        clock.tick(60)
    pygame.quit()
if __name__ == "__main__":
    try:
        main()
    except:
        traceback.print_exc()
        pygame.quit()
        input()