Snake game made in Python

Question

I made a snake game with /some/ code from thenewboston's tutorials when I had just started Python. I think it wasn't a good idea to start game development right away since I didn't even know if what I did was correctly coded.

I didn't use classes and objects since I didn't know how to use them. I'm sure this needs a lot of improving.

Game.py

import pygame
import random
pygame.init()
pygame.mixer.music.load("music.mp3")
pygame.mixer.music.play
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
GREEN = (0, 155, 0)
RED = (255, 0, 0)
CYAN = (0, 255, 255)
DARK_CYAN = (123, 104, 238)
YELLOW = (247, 255, 0)
game_title = 'Retro Worm'
display_width = 800
display_height = 600
background_color = BLACK
snake_color = DARK_CYAN
energy_color = DARK_CYAN
polygon_powerup_color = (random.randrange(255), random.randrange(255), random.randrange(255))
game_display = pygame.display.set_mode((display_width, display_height))
pygame.display.set_caption(game_title)
global block_size
block_size = 10
clock = pygame.time.Clock()
font = pygame.font.SysFont(None, 25)
def get_collision(p_x, p_y, target_x, target_y, width, height):
 if p_x >= target_x and p_x <= target_x + width:
 if p_y >= target_y and p_y <= target_y + height:
 return True
 return False
def draw_bombs(b_x, b_y, bw, bh):
 pygame.draw.rect(game_display, YELLOW, [b_x[0], b_y[0], bw, bh])
 pygame.draw.rect(game_display, YELLOW, [b_x[1], b_y[1], bw, bh])
 pygame.draw.rect(game_display, YELLOW, [b_x[2], b_y[2], bw, bh])
 pygame.draw.rect(game_display, YELLOW, [b_x[3], b_y[3], bw, bh])
def set_by_bounds(item_x, item_y, width, height):
 if item_x >= display_height or item_y <= 0:
 item_x = [random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size)]
 item_y = [0, 0, 0, 0]
 return item_x, item_y
def snake(width, height, snakelist):
 for x_and_y in snakelist:
 pygame.draw.rect(game_display, snake_color, [x_and_y[0], x_and_y[1], width, height])
 pygame.draw.rect(game_display, WHITE, [x_and_y[0] + 2, x_and_y[1] + 2, width, height])
def create_bombs(amount):
 bomb_x = list()
 bomb_y = list()
 for am in range(amount):
 bomb_x.append(random.randrange((display_width - block_size) - 30))
 bomb_y.append(30)
def message_to_screen(msg, color):
 screen_text = font.render(msg, True, color)
 game_display.blit(screen_text, [200, 300])
def display_score(score):
 screen_text = font.render(score, True, YELLOW)
 game_display.blit(screen_text, [50, 50])
def game_loop():
 pygame.mixer.music.rewind()
 pygame.mixer.music.play(10000)
 fps = 30
 block_size = 10
 running = True
 game_over = False
 lead_x = display_width / 2
 lead_y = display_height / 2
 lead_x_change = 0
 lead_y_change = 0
 powerup_x = 0
 powerup_y = 0
 snake_list = list()
 snake_length = 1
 rand_apple_x = round(random.randrange(0, display_width - block_size) / float(block_size)) * block_size + block_size
 rand_apple_y = round(random.randrange(0, display_height - block_size) / float(block_size)) * block_size + block_size
 score = 0
 score_add = 10
 # BOMBS
 # UP BOMBS
 up_bombs_x = [random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size)]
 up_bombs_y = [0,
 0,
 0,
 0]
 # DOWN BOMBS
 down_bombs_x = [random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size)]
 down_bombs_y = [display_height,
 display_height,
 display_height,
 display_height]
 # LEFT BOMBS
 left_bombs_x = [0,
 0,
 0,
 0]
 left_bombs_y = [random.randrange(0, display_height - block_size),
 random.randrange(0, display_height - block_size),
 random.randrange(0, display_height - block_size),
 random.randrange(0, display_height - block_size)]
 # RIGHT BOMBS
 right_bombs_x = [display_width,
 display_width,
 display_width,
 display_width]
 right_bombs_y = [random.randrange(0, display_height - block_size),
 random.randrange(0, display_height - block_size),
 random.randrange(0, display_height - block_size),
 random.randrange(0, display_height - block_size)]
 background_color = (random.randrange(255), random.randrange(255), random.randrange(255))
 while running:
 while game_over:
 game_display.fill(background_color)
 message_to_screen('Game over. Press R to restart or Q to quit.', DARK_CYAN)
 pygame.display.update()
 for event in pygame.event.get():
 if event.type == pygame.QUIT:
 running = False
 game_over = False
 if event.type == pygame.KEYDOWN:
 if event.key == pygame.K_q:
 running = False
 game_over = False
 if event.key == pygame.K_r:
 game_loop()
 # Event handling
 for event in pygame.event.get():
 if event.type == pygame.QUIT:
 running = False
 # Key handling
 if event.type == pygame.KEYDOWN:
 if event.key == pygame.K_LEFT or event.key == pygame.K_a:
 lead_x_change = -block_size
 lead_y_change = 0
 elif event.key == pygame.K_RIGHT or event.key == pygame.K_d:
 lead_x_change = block_size
 lead_y_change = 0
 if event.key == pygame.K_UP or event.key == pygame.K_w:
 lead_y_change = -block_size
 lead_x_change = 0
 elif event.key == pygame.K_DOWN or event.key == pygame.K_s:
 lead_y_change = block_size
 lead_x_change = 0
 elif event.key == pygame.K_f:
 block_size += 10
 elif event.key == pygame.K_e:
 block_size -= 10
 # Map limits
 if lead_x >= display_width or lead_x < 0 or lead_y >= display_height or lead_y < 0:
 game_over = True
 lead_x += lead_x_change
 lead_y += lead_y_change
 up_bombs_y[0] += block_size
 up_bombs_y[1] += block_size
 up_bombs_y[2] += block_size
 up_bombs_y[3] += block_size
 left_bombs_x[0] += block_size
 left_bombs_x[1] += block_size
 left_bombs_x[2] += block_size
 left_bombs_x[3] += block_size
 down_bombs_y[0] -= block_size
 down_bombs_y[1] -= block_size
 down_bombs_y[2] -= block_size
 down_bombs_y[3] -= block_size
 right_bombs_x[0] += block_size
 right_bombs_x[1] += block_size
 right_bombs_x[2] += block_size
 right_bombs_x[3] += block_size
 powerup_x += 5
 powerup_y += 5
 # Clean state
 game_display.fill(background_color)
 # Draw
 pygame.draw.rect(game_display, energy_color, [rand_apple_x, rand_apple_y, block_size, block_size])
 draw_bombs(up_bombs_x, up_bombs_y, block_size, block_size);
 if 200:
 pygame.draw.rect(game_display, YELLOW, [left_bombs_x[0], left_bombs_y[0], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [left_bombs_x[1], left_bombs_y[1], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [left_bombs_x[2], left_bombs_y[2], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [left_bombs_x[3], left_bombs_y[3], block_size, block_size])
 if score >= 300:
 pygame.draw.rect(game_display, YELLOW, [down_bombs_x[0], down_bombs_y[0], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [down_bombs_x[1], down_bombs_y[1], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [down_bombs_x[2], down_bombs_y[2], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [down_bombs_x[3], down_bombs_y[3], block_size, block_size])
 if score >= 500:
 pygame.draw.rect(game_display, YELLOW, [right_bombs_x[0], right_bombs_y[0], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [right_bombs_x[1], right_bombs_y[1], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [right_bombs_x[2], right_bombs_y[2], block_size, block_size])
 pygame.draw.rect(game_display, YELLOW, [right_bombs_x[3], right_bombs_y[3], block_size, block_size])
 pygame.draw.circle(game_display, DARK_CYAN, [powerup_x, powerup_x], 10)
 while len(snake_list) > 2:
 del snake_list[0]
 snake_head = list()
 snake_head.append(lead_x)
 snake_head.append(lead_y)
 snake_list.append(snake_head)
 if len(snake_list) > snake_length:
 del snake_list[0]
 snake(block_size, block_size, snake_list)
 display_score('Score: ' + str(score))
 pygame.display.update()
 # --------------- COLLISION -----------------------
 # BOMBS COLLISION
 for index in range(len(up_bombs_x) - 1):
 if get_collision(lead_x, lead_y, up_bombs_x[index], up_bombs_y[index], block_size, block_size):
 game_over = True
 for index in range(len(left_bombs_x) - 1):
 if get_collision(lead_x, lead_y, left_bombs_x[index], left_bombs_y[index], block_size, block_size):
 game_over = True
 # APPLE COLLISION
 if get_collision(rand_apple_x, rand_apple_y, lead_x, lead_y, block_size, block_size):
 rand_apple_x = round(random.randrange(0, display_width - block_size) / block_size) * block_size
 rand_apple_y = round(random.randrange(0, display_height - block_size) / block_size) * block_size
 snake_length += 1
 score += score_add
 display_score(str(score))
 background_color = (random.randrange(255), random.randrange(255), random.randrange(255))
 # POWER-UP COLLISION
 if get_collision(powerup_x, powerup_y, lead_x, lead_y, block_size * 2, block_size * 2):
 score += 50
 powerup_x = 1000
 powerup_y = 1000
 # CHECK IF OUT OF BOUNDS
 if up_bombs_y[0] >= display_height + 200 or up_bombs_y[0] <= 0:
 up_bombs_x = [random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size)]
 up_bombs_y = [0, 0, 0, 0]
 if left_bombs_x[0] >= display_width + 200 or left_bombs_y[0] <= 0:
 left_bombs_y = [random.randrange(0, display_width - block_size * 2),
 random.randrange(0, display_width - block_size * 2),
 random.randrange(0, display_width - block_size * 2),
 random.randrange(0, display_width - block_size * 2),
 random.randrange(0, display_width - block_size * 2)]
 left_bombs_x = [0, 0, 0, 0]
 if down_bombs_y[0] <= -300:
 down_bombs_x = [random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size),
 random.randrange(0, display_width - block_size)]
 down_bombs_y = [display_height, display_height, display_height, display_height]
 # ------------------------------------
 # POWER-UP POSITION RANDOMIZATION
 random_spawn_powerup = random.randrange(1000)
 if powerup_x >= display_width or powerup_y >= display_height:
 if random_spawn_powerup == 3:
 powerup_x = 0
 powerup_y = 0
 clock.tick(fps)
 pygame.quit()
 quit()
# CODE
game_loop()

• Gareth Rees: See this question and its answer.
• inyoot: error: music not loaded
• Ethan Bierlein: @inyoot You're probably getting that error because you don't have a music.mp3 file.
• inyoot: Yup. I've commented it out. Runs pretty fast. Snake with moving obstacle.

Answer 1

First off, for a beginner, this code is actually quite good! I do have some suggestions for improvement though, specifically regarding documentation and such.

• First off, you did great with PEP8. The only errors I'm getting back are that there are too many lines greater than 79 characters long. You do have an unnecessary semicolon on line 233 though.
• You have a lot of code in your game_loop function. I would recommend separating this function into smaller functions, each with their own individual purpose. This will help improve readability as well.
• You're missing documentation in your code. The only comments that I see are useless ones like # DOWN BOMBS, or # Event handling. Comments should be descriptive, and describe a block of code well. For functions, you should use docstrings to describe what they do. Here's an example.

---

def my_function(args):
 """
 Flesh this docstring out with useful
 information about the function.
 """
 # Code goes here

---

• Another thing that really sticks out here is your naming. The variables you have at the top of the file are mostly all constants. If you have a constant variable (value doesn't change), it's name should be in all uppercase. For example, if a variable has the name BLOCK_SIZE, we can tell that it's a constant describing the block size.
• With the issue of naming continued, a few of your variable names are a little hard to understand, for example, from looking at the function argument b_x, I don't know what it does. If it's an abbreviation of something, and it's this short, don't abbreviate it.
• My final tip is to format lists, dictionaries, and tuples like the below example. Not in the current form you're doing it. It mostly just improves readability.

---

my_list = [
 an_item
 ...
]

---

In short, your code is pretty good! I hope that this answer helped you improve your code!

• Vicente Bermúdez: Great answer! I noticed in some cases that I could use the function ` draw_bombs` more, instead of drawing each rectangle one by one. The variable b_x is an array of all the bombs x coordinate. Thanks for the nice answer. :)
• Ethan Bierlein: @VicenteBermúdez No problem! :)