Particles tutorial 1

Let’s talk about particles in python and pygame. Let’s show a very simple effect, in this first part. In the next one we will see how to use it in a game.

The video

The code

import pygame
import random


class Particles:
    ''' position x y
        color col
        starting pos sx xy '''

    def __init__(self, x=515, y=500, col=(0, 0, 0)):
        "Initial position with random height"
        self.x, self.y = 515, random.randint(0, y)
        self.sx = x
        self.sy = y
        self.col = col

    def move(self):
        "When particle reaches top goes back down"
        if self.y < 0:
            self.x = self.sx
            self.y = self.sy
        else:
            self.y -= 1
        self.x += random.randrange(-1, 2)
        pygame.draw.circle(screen, self.col, (self.x, self.y), 2)


def particles_list(number: int) -> list:
    "Create a list of particles"
    particles = []
    for part in range(number):
        col = (255, 255, 0) if part % 2 > 0 else (255, 0, 0)
        particles.append(Particles(col=col))
    return particles


def def_close_window():
    "Close the window with [x] button or ESC"
    loop = 1
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            loop = 0
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                loop = 0
    return loop


def show_particles(particles):
    for p in particles:
        p.move()


pygame.init()
screen = pygame.display.set_mode((1000, 600))
clock = pygame.time.Clock()


def start():
    particles = particles_list(100)

    loop = 1
    while loop:
        loop = def_close_window()
        screen.fill((0, 0, 0))
        show_particles(particles)

        pygame.display.update()
        clock.tick(60)
    pygame.quit()


start()