Trying to figure out how to track Pygame events and organize the game's functions

Question

I\'m new to Pygame, so I\'m still struggling with the whole \"events\" concept.

Basically, my current challenge is to:

1. Get pygame.event.get() workin

Answer 1

Stick with a single main loop, and don't use threads if you don't really need them.

You already figured out that your game consists of different screens (let's call them Scene so we don't confuse it with the actual screen where we draw stuff), so the next logical step is to seperate them out from the main loop.

---

Say you have the following scenes:

• intro
• main menu
• game play

then you should create a class for each of those, which will then be responsible for drawing/event handling/whatever-needed-in-this-part.

A simple example:

import pygame
pygame.init()

class Scene(object):
    screen = None

class Intro(Scene):
    def __init__(self):
        self.c = (32, 32, 100)

    def draw(self):
        Scene.screen.fill(self.c)

    def update(self):
        # since scenes are classes, they have a state that we can modify
        r,g,b = self.c
        r += 1
        g += 1
        b += 2
        if r > 255: r = 0
        if g > 255: g = 0
        if b > 255: b = 0
        self.c = r, g, b

    def handle(self, event):
        # move to Menu-scene when space is pressed
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_SPACE:
                # returning a scene from handle or update changes the current scene
                return Menu()

class Menu(Scene):
    def draw(self):
        # draw menu
        Scene.screen.fill((200, 200, 100))

    def update(self):
        pass
        # do something

    def handle(self, event):
        # handle menu input
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_a:
                return Game()
            if event.key == pygame.K_b:
                return Intro()

class Game(Scene):
    pass # implement draw update handle

Scene.screen = pygame.display.set_mode((800, 600))

scene = Intro()
while True:
    if pygame.event.get(pygame.QUIT): break
    for e in pygame.event.get(): 
        scene = scene.handle(e) or scene
    scene = scene.update() or scene
    scene.draw()
    pygame.display.flip()

This way, you have a single mainloop, but different parts of your game are managed by seperate classes. In the simple example above, each scene knows what other scene to activate on a certain event, but this is not necessary. You could create some kind of SceneHandler that manages the transitions between the scenes. Also, you may want to have some kind of game state object that you want to pass around scenes (e.g. show your points from the game scene in your game-over scene).