How to make a simple Snake game with pyGame

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Walker AI

1. preface

At present, the tools or third-party libraries that will be used in software testing have been written , In line with the principle of not catching a sheep to collect wool , Change the track , Use this time pygame Ku wrote a simple Snake , As familiar python It's also good to practice .

2. Installation and import

Use pip install pygame Enter the installation , Import the required modules after successful installation :

import pygame,sys,random
from pygame.locals import *


among sys In order to use its exit mechanism in the future, you need to import .

3. Define the subsequent required parameters

# initialization pygame library
pygame.init()


In use pygame when , It is necessary to initialize the library , Corresponding to the following exit code , These two are a pair .

# Initialize a game interface
DISPLAY=pygame.display.set_mode((800,800))
# Set game window title
pygame.display.set_caption(' snake ')


After writing the above code , Click Run to have a flashing interface , This is normal , Because nothing is running .

# Define a variable to control the game speed
FPSCLOCK=pygame.time.Clock()

# Define color
BLACK=pygame.Color(0,0,0)
WHITE=pygame.Color(255,255,255)
RED=pygame.Color(255,0,0)

#  Define the initial position of the snake head
snake_Head=[100,100]
#  Define the initial length of a snake , Because the interfaces are 20*20 So the length is minus 20
snake_Body=[[80,100], [60,100]]
# #  The initial direction of the snake
direction="right"
#  Define variables that change direction , Key
changeDirection = direction
# Define the initial food location
food_Postion = [300,300]
#  Define food status ,0 Means to be eaten ,1 It means not being eaten
food_Total = 1


All the above are used to define the parameters that will be used later .

4. Draw snakes and food

# Draw greedy snake
def drawSnake(snake_Body):
 for i in snake_Body:
 pygame.draw.rect(DISPLAY,WHITE,Rect(i[0],i[1],20,20))

# Draw food location
def drawFood(food_Postion):
 pygame.draw.rect(DISPLAY,RED,Rect(food_Postion[0],food_Postion[1],20,20))


above pygame.draw.rect(DISPLAY,RED,Rect(food_Postion[0],food_Postion[1],20,20)) draw yes pygame Drawing module of ,rect in DISPLAY Is to draw colors on the game interface we set 、 The area of the drawn rectangle 、 The width and height of the rectangle .

5. Game rules and operation

def gameover():
 # sign out pygame
 pygame.quit()
 # Exit procedure
 sys.exit()


The exit set here is the same as the above pygame.init()  Corresponding .

game_flag=True
while game_flag:
 # Render the background color
 DISPLAY.fill(BLACK)
 # Draw a greedy snake
 drawSnake(snake_Body)
 # Draw the food position
 drawFood(food_Postion)


Here the background is set to black , Corresponds to the setting in the defined color , Match the position of snake and food with the above  .

 # Increase game speed
 game_speed=1+len(snake_Body)//3
 # Refresh the display layer , Greedy snakes and food move every time , Will refresh the display layer
 pygame.display.flip()
 FPSCLOCK.tick(game_speed)
 for event in pygame.event.get():
 if event.type==QUIT:
 pygame.quit()
 sys.exit()


Here is the speed of the game , And the movement speed increases after eating food .

 elif event.type == KEYDOWN:
 #  If it's a right arrow or d, The snake moves to the right
 if event.key == K_RIGHT or event.key == K_d:
 changeDirection = 'right'
 #  If it's an arrow or a, The snake moves to the left
 if event.key == K_LEFT or event.key == K_a:
 changeDirection = 'left'
 if event.key == K_UP or event.key == K_w:
 changeDirection = 'up'
 if event.key == K_DOWN or event.key == K_s:
 changeDirection = 'down'
 #  Click on esc, sign out
 if event.key == KSCAN_ESCAPE:
 pygame.event.post(pygame.event.Event(QUIT))

 #  Confirm the direction , Determine if the reverse direction is entered
 if changeDirection == 'right' and not direction == 'left':
 direction = changeDirection
 if changeDirection == 'left' and not direction == 'right':
 direction = changeDirection
 if changeDirection == 'up' and not direction == 'down':
 direction = changeDirection
 if changeDirection == 'down' and not direction == 'up':
 direction = changeDirection

 # Move the snake's head according to the direction
 if direction=='right':
 snake_Head[0]+=20
 if direction=='left':
 snake_Head[0]-=20
 if direction=='up':
 snake_Head[1]-=20
 if direction=='down':
 snake_Head[1]+=20


Note that the words in the quotation marks here should be consistent with the words in the initial direction of the snake , Otherwise, there will be problems at runtime if changeDirection == 'right' and not direction == 'left':  It means that you can use “→” perhaps “D” Move right , The following is also true if changeDirection == 'right' and not direction == 'left': It means if you press when walking on the right “A” perhaps “←” It doesn't work , The following is also true if direction=='right':snake_Head[0]+=20  It means to click “→” perhaps “D” Move one space to the right , Because the grid is 20*20 So one of them is 20

 # Increase the length of the snake
 snake_Body.insert(0,list(snake_Head))
 # Judge whether you have food
 if snake_Head[0] == food_Postion[0] and snake_Head[1] == food_Postion[1]:
 food_Total = 0
 else:
 snake_Body.pop() 


snake_Body.pop() It means that if you don't eat it, you won't add any new food , Without this code , It will cause the snake to increase its length without food .

 if food_Total == 0:
 x = random.randrange(1, 32)
 y = random.randrange(1, 24)
 food_Postion = [int(x * 20), int(y * 20)]
 food_Total = 1


This means that if the food is eaten , Status as 0 Words , Generate a random location .

 if snake_Head[0] > 800 or snake_Head[0] < 0:
 gameover()
 elif snake_Head[0] > 800 or snake_Head[0] < 0:
 gameover()
 #  If you meet yourself
 for body in snake_Body[1:]:
 if snake_Head[0] == body[0] and snake_Head[1] == body[1]:
 gameover()


if snake_Head[0] > 800 or snake_Head[0] < 0: It means to exit the game at the boundary ,800 Is the overall set interface size

6. Finished product display

7. Complete code

import pygame,sys,random
from pygame.locals import *

# initialization pygame library
pygame.init()
# Initialize a game interface
DISPLAY=pygame.display.set_mode((800,800))
# Set game window title
pygame.display.set_caption(' snake ')

# Define a variable to control the game speed
FPSCLOCK=pygame.time.Clock()

# Define color
BLACK=pygame.Color(0,0,0)
WHITE=pygame.Color(255,255,255)
RED=pygame.Color(255,0,0)

#  Define the initial position of the snake head
snake_Head=[100,100]
#  Define the initial length of a snake , Because the interfaces are 20*20 So the length is minus 20
snake_Body=[[80,100], [60,100],[40,100]]
# #  The initial direction of the snake
direction="right"
#  Define variables that change direction , Key
changeDirection = direction
# Define the initial food location
food_Postion = [300,300]
#  Define food status ,0 Means to be eaten ,1 It means not being eaten
food_Total = 1

# Draw greedy snake
def drawSnake(snake_Body):
 for i in snake_Body:
 pygame.draw.rect(DISPLAY,WHITE,Rect(i[0],i[1],20,20))

# Draw food location
def drawFood(food_Postion):
 pygame.draw.rect(DISPLAY,RED,Rect(food_Postion[0],food_Postion[1],20,20))

def gameover():
 # sign out pygame
 pygame.quit()
 # Exit procedure
 sys.exit()


game_flag=True
while game_flag:
 # Render the background color
 DISPLAY.fill(BLACK)
 # Draw a greedy snake
 drawSnake(snake_Body)
 # Draw the food position
 drawFood(food_Postion)
 # Increase game speed
 game_speed=1+len(snake_Body)//3
 # Refresh the display layer , Greedy snakes and food move every time , Will refresh the display layer
 pygame.display.flip()
 FPSCLOCK.tick(game_speed)
 for event in pygame.event.get():
 if event.type==QUIT:
 pygame.quit()
 sys.exit()

 elif event.type == KEYDOWN:
 #  If it's a right arrow or d, The snake moves to the right
 if event.key == K_RIGHT or event.key == K_d:
 changeDirection = 'right'
 #  If it's an arrow or a, The snake moves to the left
 if event.key == K_LEFT or event.key == K_a:
 changeDirection = 'left'
 if event.key == K_UP or event.key == K_w:
 changeDirection = 'up'
 if event.key == K_DOWN or event.key == K_s:
 changeDirection = 'down'
 #  Click on esc, sign out
 if event.key == KSCAN_ESCAPE:
 pygame.event.post(pygame.event.Event(QUIT))

 #  Confirm the direction , Determine if the reverse direction is entered
 if changeDirection == 'right' and not direction == 'left':
 direction = changeDirection
 if changeDirection == 'left' and not direction == 'right':
 direction = changeDirection
 if changeDirection == 'up' and not direction == 'down':
 direction = changeDirection
 if changeDirection == 'down' and not direction == 'up':
 direction = changeDirection

 # Move the snake's head according to the direction
 if direction=='right':
 snake_Head[0]+=20
 if direction=='left':
 snake_Head[0]-=20
 if direction=='up':
 snake_Head[1]-=20
 if direction=='down':
 snake_Head[1]+=20
 # Increase the length of the snake
 snake_Body.insert(0,list(snake_Head))
 # Judge whether you have food
 if snake_Head[0] == food_Postion[0] and snake_Head[1] == food_Postion[1]:
 food_Total = 0
 else:
 snake_Body.pop()

 if food_Total == 0:
 x = random.randrange(1, 32)
 y = random.randrange(1, 24)
 food_Postion = [int(x * 20), int(y * 20)]
 food_Total = 1

 if snake_Head[0] > 800 or snake_Head[0] < 0:
 gameover()
 elif snake_Head[0] > 800 or snake_Head[0] < 0:
 gameover()
 #  If you meet yourself
 for body in snake_Body[1:]:
 if snake_Head[0] == body[0] and snake_Head[1] == body[1]:
 gameover()


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