Session 10: Coach notes

Mon, 01 Jan 0001 00:00:00 +0000

Goal of this session This is an open-ended session. There is no “Basic checkpoint” with fixed learning goals: the goal is that every ninja builds something they came up with themselves and are proud of. Success criteria per level: Basic ninja: has a working pygame window with at least one interactive element (moving, shooting, or collision). Advanced ninja: combines two or more mechanics from earlier sessions into one coherent game. Expert ninja: has a fully playable game with a beginning, an end and feedback (score, lives, win/lose screen). Preparation (30 min before the session) Look through the earlier cheatsheets again: ninjas will ask questions about patterns from sessions 1 to 9. The session 10 cheatsheet combines everything; keep it at hand. Prepare inspiration material: printouts of the genre options or a slide with screenshot examples of simple games help ninjas who get stuck choosing a concept. Reminder: the game doesn’t have to be finished. Say this explicitly in the intro. A ninja who built a working movement mechanic has succeeded just as much as someone with a complete game. Schedule (3 hours) Time Activity 0:00 to 0:15 Welcome, explaining the free session, choosing a concept 0:15 to 0:30 Making a plan (3 questions on paper or in code) 0:30 to 2:15 Building: coaches walk around and help one on one 2:15 to 2:45 Finishing up + preparing the showcase 2:45 to 3:00 Showcase: everyone presents for 1 to 2 minutes The coach’s role today Today you are less of an instructor and more of a sparring partner:

Session 10: Cheatsheet (all sessions)

Mon, 01 Jan 0001 00:00:00 +0000

An overview of all the patterns from sessions 1 to 9. Use it as a reference while you build your own game. Pygame game loop (session 6+) import pygame pygame.init() WIDTH, HEIGHT = 800, 500 screen = pygame.display.set_mode((WIDTH, HEIGHT)) pygame.display.set_caption("My Game") clock = pygame.time.Clock() font = pygame.font.SysFont(None, 36) running = True while running: for event in pygame.event.get(): if event.type == pygame.QUIT: running = False if event.type == pygame.KEYDOWN: if event.key == pygame.K_SPACE: pass # action on SPACE screen.fill((20, 20, 50)) # update logic here # draw logic here pygame.display.flip() clock.tick(60) pygame.quit() Pgzrun game loop (sessions 1 to 5) import pgzrun WIDTH = 600 HEIGHT = 400 def draw(): screen.fill((20, 20, 50)) def update(): pass # replace with your own logic pgzrun.go() Keyboard # Pgzrun style: if keyboard.left: speler.x -= 5 # Pygame style: keys = pygame.key.get_pressed() if keys[pygame.K_LEFT]: speler_rect.x -= 5 if keys[pygame.K_RIGHT]: speler_rect.x += 5 if keys[pygame.K_UP]: speler_rect.y -= 5 if keys[pygame.K_DOWN]: speler_rect.y += 5 Mouse input # Position: mx, my = pygame.mouse.get_pos() # Clicking (in the event loop): if event.type == pygame.MOUSEBUTTONDOWN: if event.button == 1: # left mouse button pass Actor / Sprite (pgzrun) speler = Actor('speler') # loads images/speler.png speler.pos = (300, 380) def draw(): speler.draw() if speler.colliderect(ster): pass # collision! Creating and drawing a Rect (pygame) speler_rect = pygame.Rect(x, y, breedte, hoogte) pygame.draw.rect(screen, (0, 128, 255), speler_rect) # Circle: pygame.draw.circle(screen, (255, 255, 0), (x, y), straal) # Line: pygame.draw.line(screen, (255, 0, 0), (x1, y1), (x2, y2), dikte) Collision detection # Two Rects: if rect_a.colliderect(rect_b): pass # Point in Rect: if rect.collidepoint(mx, my): pass # Pgzrun: if actor_a.colliderect(actor_b): pass Gravity and jumping (session 6) GRAVITY = 0.5 vel_y = 0 on_ground = False # Every frame: vel_y += GRAVITY speler_rect.y += int(vel_y) for platform in platforms: if speler_rect.colliderect(platform) and vel_y > 0: speler_rect.bottom = platform.top vel_y = 0 on_ground = True # Jumping: if keys[pygame.K_SPACE] and on_ground: vel_y = -12 Classes (session 7) class Vijand: def __init__(self, x, y): self.x = x self.y = y self.alive = True def update(self): self.y += 2 def draw(self, screen): pygame.draw.circle(screen, (0, 200, 0), (int(self.x), int(self.y)), 15) # Using it: v = Vijand(200, 0) v.update() v.draw(screen) Inheritance (session 7) class SlingerVijand(Vijand): def __init__(self, x, y): super().__init__(x, y) self.timer = 0 self.start_x = x def update(self): import math self.timer += 0.05 self.x = self.start_x + math.sin(self.timer) * 60 self.y += 1.5 Scrolling background (session 8) scroll_x = 0 speed = 4 # Every frame: scroll_x -= speed if scroll_x <= -WIDTH: scroll_x = 0 screen.blit(bg_image, (int(scroll_x), 0)) screen.blit(bg_image, (int(scroll_x) + WIDTH, 0)) Spawning objects (session 8) import random SPAWN_EVENT = pygame.USEREVENT + 1 pygame.time.set_timer(SPAWN_EVENT, 1500) for event in pygame.event.get(): if event.type == SPAWN_EVENT: objecten.append(pygame.Rect(WIDTH, random.randint(50, HEIGHT - 100), 30, 60)) # Move and remove: for obj in objecten[:]: obj.x -= speed if obj.x < -obj.width: objecten.remove(obj) Drawing an HP bar (session 9) MAX_HP = 100 # Background: pygame.draw.rect(screen, (80, 0, 0), (10, 10, 300, 20)) # Filled part: breedte = max(0, int(300 * hp / MAX_HP)) pygame.draw.rect(screen, (220, 0, 0), (10, 10, breedte, 20)) State machine / phases (session 9) if hp > 50: fase = 1 snelheid = 3 elif hp > 25: fase = 2 snelheid = 5 else: fase = 3 snelheid = 7 Keeping track of bullets kogels = [] # Create (on a key press): kogels.append(pygame.Rect(speler_rect.centerx - 3, speler_rect.top - 15, 6, 15)) # Move and remove: for k in kogels[:]: k.y -= 8 if k.y < 0: kogels.remove(k) continue pygame.draw.rect(screen, (255, 255, 0), k) # Collision with enemy: if k.colliderect(vijand_rect): kogels.remove(k) vijand.alive = False score += 1 break Sound (session 6) pygame.mixer.init() sprong_snd = pygame.mixer.Sound("sounds/sprong.wav") sprong_snd.play() # Background music: pygame.mixer.music.load("sounds/muziek.mp3") pygame.mixer.music.play(-1) # -1 = repeat forever Drawing text font = pygame.font.SysFont(None, 36) tekst = font.render(f"Score: {score}", True, (255, 255, 255)) screen.blit(tekst, (10, 10)) # Centred: screen.blit(tekst, (WIDTH // 2 - tekst.get_width() // 2, HEIGHT // 2)) Score and global variables score = 0 # outside all functions # In pgzrun update(): global score score += 1 # In pygame (score is already global if it is outside the loop): score += 1 Random numbers import random x = random.randint(0, WIDTH) # whole number between 0 and WIDTH k = random.choice(['red', 'blue']) # random element from a list r = random.random() # floating point number between 0.0 and 1.0 Timer pattern (frame-based) timer = 0 interval = 90 # every 90 frames (= 1.5 sec at 60 FPS) # Every frame: timer += 1 if timer >= interval: timer = 0 # do something Win and game over screen # Game over: screen.fill((0, 0, 0)) go = font.render("GAME OVER", True, (220, 0, 0)) screen.blit(go, (WIDTH // 2 - go.get_width() // 2, HEIGHT // 2)) pygame.display.flip() pygame.time.wait(3000) # Win: win = font.render("You win!", True, (255, 220, 0)) screen.blit(win, (WIDTH // 2 - win.get_width() // 2, HEIGHT // 2)) pygame.display.flip() pygame.time.wait(3000)

Session 10: Demo recording

Mon, 01 Jan 0001 00:00:00 +0000

Session 10 is a free session: there is no fixed solution, so no demo GIF for the session page. Alternative: showcase photos During the showcase, take photos of the ninjas’ screens (with their permission). You can put a selection on the session page as a gallery of what the group built. Add photos in static/sessions/10-my-game/ and link to them via: ![Game by ninja X](/sessions/10-my-game/naam.jpg) Optional: your own starter demo If you want to show an example game that demonstrates the starter, run:

Session 10: My Game :: CoderDojo Python & Pygame

Session 10: Coach notes

Session 10: Cheatsheet (all sessions)

Session 10: Demo recording