Bike Survival Game using Pygame in Python

 

Code:

import pygame

import random

# Initialize Pygame

pygame.init()

# Screen dimensions

WIDTH, HEIGHT = 600, 800

screen = pygame.display.set_mode((WIDTH, HEIGHT))

pygame.display.set_caption("Moving Bike Game")

# Colors

WHITE = (255, 255, 255)

BLACK = (0, 0, 0)

GRAY = (50, 50, 50)

YELLOW = (255, 255, 0)

RED = (200, 0, 0)

# Clock

clock = pygame.time.Clock()

FPS = 60

# Load bike image

bike_img = pygame.image.load("bike.png")

bike_img = pygame.transform.scale(bike_img, (50, 100))  # Resize if needed

bike_width, bike_height = bike_img.get_size()

bike_x = WIDTH // 2 - bike_width // 2

bike_y = HEIGHT - bike_height - 30

bike_speed = 7

# Road

road_width = 300

road_x = WIDTH // 2 - road_width // 2

road_lines = []

line_height = 80

line_width = 10

line_speed = 7

for i in range(0, HEIGHT, line_height * 2):

    road_lines.append(pygame.Rect(WIDTH//2 - line_width//2, i, line_width, line_height))

# Obstacles

obstacle_width, obstacle_height = 50, 100

obstacle_speed = 7

obstacles = []

# Score

score = 0

font = pygame.font.SysFont(None, 35)

def draw_bike(x, y):

    screen.blit(bike_img, (x, y))

def draw_obstacles(obstacles):

    for obs in obstacles:

        pygame.draw.rect(screen, RED, obs)

def draw_road():

    pygame.draw.rect(screen, GRAY, (road_x, 0, road_width, HEIGHT))

    for line in road_lines:

        pygame.draw.rect(screen, YELLOW, line)

def move_lines():

    for line in road_lines:

        line.y += line_speed

        if line.y > HEIGHT:

            line.y = -line_height

def display_score(score):

    text = font.render(f"Score: {score}", True, BLACK)

    screen.blit(text, (10, 10))

# Game loop

running = True

while running:

    screen.fill(WHITE)

    

    # Event handling

    for event in pygame.event.get():

        if event.type == pygame.QUIT:

            running = False

    

    # Bike movement

    keys = pygame.key.get_pressed()

    if keys[pygame.K_LEFT] and bike_x > road_x:

        bike_x -= bike_speed

    if keys[pygame.K_RIGHT] and bike_x + bike_width < road_x + road_width:

        bike_x += bike_speed

    

    # Create obstacles

    if random.randint(1, 50) == 1:

        obs_x = random.randint(road_x, road_x + road_width - obstacle_width)

        obs_y = -obstacle_height

        obstacles.append(pygame.Rect(obs_x, obs_y, obstacle_width, obstacle_height))

    

    # Move obstacles

    for obs in obstacles:

        obs.y += obstacle_speed

    

    # Remove off-screen obstacles

    obstacles = [obs for obs in obstacles if obs.y < HEIGHT]

    

    # Check collision

    bike_rect = pygame.Rect(bike_x, bike_y, bike_width, bike_height)

    for obs in obstacles:

        if bike_rect.colliderect(obs):

            running = False  # Game over

    

    # Move road lines

    move_lines()

    

    # Draw everything

    draw_road()

    draw_bike(bike_x, bike_y)

    draw_obstacles(obstacles)

    display_score(int(score))

    

    # Update score

    score += 1 / FPS

    

    pygame.display.update()

    clock.tick(FPS)

pygame.quit()

Output:

Code Explanation:

1) Importing Modules

import pygame

import random

pygame → game library for graphics, input, sound.

random → used for generating random obstacle positions.

2) Initialize Pygame

pygame.init()

Starts all pygame modules (graphics, events, fonts, etc.).

Required before using most pygame functions.

3) Screen Setup

WIDTH, HEIGHT = 600, 800

screen = pygame.display.set_mode((WIDTH, HEIGHT))

pygame.display.set_caption("Moving Bike Game")

Defines game window size: 600px wide × 800px tall.

pygame.display.set_mode → creates the window.

set_caption → gives window a title.

4) Colors

WHITE = (255, 255, 255)

BLACK = (0, 0, 0)

GRAY = (50, 50, 50)

YELLOW = (255, 255, 0)

RED = (200, 0, 0)

RGB tuples for different colors used (background, road, obstacles, lines).

5) Clock & FPS

clock = pygame.time.Clock()

FPS = 60

Clock regulates speed of the game loop.

FPS = 60 → 60 frames per second target.

6) Bike Setup

bike_img = pygame.image.load("bike.png")

bike_img = pygame.transform.scale(bike_img, (50, 100))

bike_width, bike_height = bike_img.get_size()

bike_x = WIDTH // 2 - bike_width // 2

bike_y = HEIGHT - bike_height - 30

bike_speed = 7

Loads the bike image.

Resizes to 50×100 pixels.

Gets size → (bike_width, bike_height).

Places bike near bottom center of screen.

bike_speed = 7 → movement per key press.

7) Road Setup

road_width = 300

road_x = WIDTH // 2 - road_width // 2

road_lines = []

line_height = 80

line_width = 10

line_speed = 7

Road is 300px wide, centered horizontally.

Road divider lines defined with height 80px, width 10px, moving speed 7.

Initial Divider Lines

for i in range(0, HEIGHT, line_height * 2):

    road_lines.append(pygame.Rect(WIDTH//2 - line_width//2, i, line_width, line_height))

Creates vertical dashed yellow lines down the middle.

Each line is a Rect object (rectangle).

Placed every 160px apart (line_height * 2).

8) Obstacles

obstacle_width, obstacle_height = 50, 100

obstacle_speed = 7

obstacles = []

Obstacles are red rectangles (50×100).

They move down at speed 7.

Stored in list obstacles.

9) Score Setup

score = 0

font = pygame.font.SysFont(None, 35)

Score starts at 0.

Font object created to draw score text on screen.

10) Helper Functions

Draw Bike

def draw_bike(x, y):

    screen.blit(bike_img, (x, y))

Renders bike image at given (x, y) position.

Draw Obstacles

def draw_obstacles(obstacles):

    for obs in obstacles:

        pygame.draw.rect(screen, RED, obs)

Draws each red obstacle rectangle.

Draw Road

def draw_road():

    pygame.draw.rect(screen, GRAY, (road_x, 0, road_width, HEIGHT))

    for line in road_lines:

        pygame.draw.rect(screen, YELLOW, line)

Draws gray road and yellow divider lines.

Move Road Lines

def move_lines():

    for line in road_lines:

        line.y += line_speed

        if line.y > HEIGHT:

            line.y = -line_height

Moves yellow lines downward.

If a line goes off screen → reset above screen.

Display Score

def display_score(score):

    text = font.render(f"Score: {score}", True, BLACK)

    screen.blit(text, (10, 10))

Creates score text image.

Draws at top-left corner.

11) Game Loop

running = True

while running:

Main loop that keeps the game running until player quits or crashes.

Event Handling

for event in pygame.event.get():

    if event.type == pygame.QUIT:

        running = False

Checks for window close event.

If closed → stop game loop.

Bike Movement

keys = pygame.key.get_pressed()

if keys[pygame.K_LEFT] and bike_x > road_x:

    bike_x -= bike_speed

if keys[pygame.K_RIGHT] and bike_x + bike_width < road_x + road_width:

    bike_x += bike_speed

Left arrow → move bike left (within road bounds).

Right arrow → move bike right (within road bounds).

Create Obstacles

if random.randint(1, 50) == 1:

    obs_x = random.randint(road_x, road_x + road_width - obstacle_width)

    obs_y = -obstacle_height

    obstacles.append(pygame.Rect(obs_x, obs_y, obstacle_width, obstacle_height))

Random chance (1/50) each frame to spawn an obstacle.

Obstacle appears above screen (-obstacle_height) and moves downward.

Move Obstacles

for obs in obstacles:

    obs.y += obstacle_speed

Shifts each obstacle downward every frame.

Remove Off-Screen Obstacles

obstacles = [obs for obs in obstacles if obs.y < HEIGHT]

Keeps only those obstacles still on screen.

Collision Check

bike_rect = pygame.Rect(bike_x, bike_y, bike_width, bike_height)

for obs in obstacles:

    if bike_rect.colliderect(obs):

        running = False

Converts bike to rectangle.

If bike overlaps any obstacle → crash → game ends.

Move Road Lines

move_lines()

Keeps divider lines scrolling.

Draw Everything

draw_road()

draw_bike(bike_x, bike_y)

draw_obstacles(obstacles)

display_score(int(score))

Renders road, bike, obstacles, and score text.

Update Score

score += 1 / FPS

Score increases gradually with time.

Dividing by FPS ensures score = time in seconds.

Update Screen

pygame.display.update()

clock.tick(FPS)

pygame.display.update() → refresh screen with new frame.

clock.tick(FPS) → controls speed so game runs at 60 FPS.

12) Quit Game

pygame.quit()

Closes pygame window when game ends.