Python Powerhouse Days 3/4

Pygame Setup

100

This function must be called first before anything else in Pygame

What is pygame.init()?

200

This is what pygame.display.set_caption("My Game") does

What is it sets the title of the game window?

300

This is what happens if you forget pygame.display.flip() at the end of your game loop

What is nothing appears on screen... the frame never gets shown?

400

This is what this code does and what color the window will be: (two things)

screen = pygame.display.set_mode((800, 600)) screen.fill((255, 165, 0)) 

pygame.display.flip()

What is it creates an 800x600 window and fills it orange?

500

This is what is wrong with this Pygame setup: 

import pygame

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

pygame.init()

What is pygame.init() must be called BEFORE pygame.display.set_mode() — the order is wrong?

Coordinates & Colors

100

In Pygame, this is the direction Y increases — opposite of math class

What is downward?

200

This is the RGB value for pure white

What is (255, 255, 255)?

300

This is where this coordinate sits on an 800x600 screen: (400, 300)

What is the exact center of the screen?

400

This is the color that (128, 0, 128) makes

What is purple?

500

A student wants to draw something in the bottom right corner of an 800x600 screen. They use (800, 600) as the position but nothing appears. This is why

What is (800, 600) is outside the screen? In Pygame (0,0) is top left so the bottom right corner is actually just inside the edges — they need to subtract the size of their shape

Drawing Shapes

100

This is the Pygame function used to draw a filled circle

What is pygame.draw.circle()?

200

This is the correct argument order for pygame.draw.rect()

What is (surface, color, (x, y, width, height))?

300

This is which shape appears on top when these two lines run in order:

pygame.draw.rect(screen, (255, 0, 0), (100, 100, 200, 200)) 

pygame.draw.circle(screen, (0, 0, 255), (200, 200), 80)  

What is the blue circle? Shapes drawn later appear on top

400

This is what pygame.draw.polygon() needs that pygame.draw.rect() does not

What is a list of (x, y) points to connect instead of just a position, width, and height?

500

DAILY DOUBLE

A student runs this code and sees nothing but a black screen even though they drew shapes. This is EXACTLY why:  (ignore the indents)

while True:

    pygame.draw.rect(screen, (255, 0, 0), (100, 100, 200, 200))

    screen.fill((0, 0, 0))

    pygame.display.flip()

What is screen.fill() is called AFTER the shapes are drawn so it paints over everything — always fill the background FIRST then draw shapes on top?

Game Loop & Movement

100

These are the 3 parts of the Pygame game loop in the correct order

What is Events → Update → Draw?

200

This is what happens to movement if you remove clock.tick(60) from the game loop

What is the game runs at hundreds of FPS making movement feel jittery and uncontrollable?

300

This is what is missing from this game loop that causes the window to freeze immediately: (ignore indents)

while True:

    screen.fill((0, 0, 0))

    pygame.draw.circle(screen, (255, 0, 0), (400, 300), 50)

    pygame.display.flip()

What is the event loop — for event in pygame.event.get()? Without it Pygame can't process the quit event and the OS thinks the program is frozen

400

This is the difference between these two and which one gives smooth continuous movement:

# A

if event.type == pygame.KEYDOWN:

    player_x -= SPEED

# B

keys = pygame.key.get_pressed()

if keys[pygame.K_LEFT]:

    player_x -= SPEED

What is Option B? Option A fires only ONCE when the key is first pressed — Option B checks every frame the key is held down giving smooth continuous movement

500

A student's player moves fine but leaves a trail of rectangles across the screen as it moves. This is the cause and the fix

What is forgetting screen.fill() at the START of the game loop? Without it the previous frame's drawings stay on screen — always fill the background first before drawing anything

Sprites & Boundaries

100

This is where you must save an image file for pygame.image.load("hero.png") to work

What is in the same folder as your Python script?

200

This is what convert_alpha() does when loading a sprite image

What is it supports transparent backgrounds so PNG files with transparency display correctly?

300

This is what is wrong with this code and how it affects performance:  (ignore indents)

while True:

    hero_img = pygame.image.load("hero.png").convert_alpha()

    screen.blit(hero_img, (player_x, player_y))

What is the image is loaded inside the game loop so it reloads from disk every single frame causing a massive slowdown — move it to BEFORE while True?

400

DAILY DOUBLE

A student runs this code and their hero moves BUT it leaves a trail of blue rectangles across the screen as it moves. This is the exact cause and the one line fix: (ignore indents)

while True:

    for event in pygame.event.get():

        if event.type == pygame.QUIT:

            pygame.quit(); sys.exit()

    keys = pygame.key.get_pressed()

    if keys[pygame.K_LEFT]: player_x -= SPEED

    if keys[pygame.K_RIGHT]: player_x += SPEED

    pygame.draw.rect(screen, (80, 140, 255),

        (player_x, player_y, SIZE, SIZE))

    pygame.display.flip()

    clock.tick(60)

What is screen.fill() is missing at the start of the draw section? Without it the previous frame's rectangle stays on screen every frame leaving a trail — add screen.fill((30, 30, 50)) before the pygame.draw.rect() line  

500

A student has clamping working perfectly at SPEED=5 but when they change to SPEED=50 the player clips through the boundaries. This is the exact reason why

What is at SPEED=50 the player moves 50 pixels per frame — if the player is at x=760 on an 800 wide screen with SIZE=50, one frame later it's at x=810 which is past the boundary before clamping can bring it back?