Python Snake Game
Snake Game in Python Pygame
If you have
a basic beginner’s knowledge about python then creating a snake game in python
is fairly easy. This blog is supposed to bring you up to speed with python
pygame and help you advance your skills in python and pygame. I am not going to
use Object Oriented Programming (OOP) model instead I will be using the
procedural method.
Let’s get into it-:
For our
game, we are going to need three modules, i.e. pygame, time, and random. The time
and random modules are usually preinstalled but you will have to install pygame
manually using the pip install pygame command.
import pygame
import time
import random
We now need
to initialize the game using the .init() function.
pygame.init()
Next we
declare the variables required for our game. We need variables containing the
colors we will use. (Colors are in RGB format). The colors are stored in tuples.
We also need the width and height of both our game window and the snake in variables.
white = (255, 255, 255)
yellow = (255, 255, 102)
black = (0, 0, 0)
red = (213, 50, 80)
green = (0, 255, 0)
blue = (50, 153, 213)
dis_width = 600
dis_height = 400
snake_block = 10
snake_speed = 5
The next
step is to set the size of the game window and also the ‘name’ of the game. It
is also important that we make sure the game will run smoothly across
different computers. Some computers are slow and others are quick so by using
the pygame.time.clock() function we make sure that the game will run uniformly
across all machines.
dis = pygame.display.set_mode((dis_width, dis_height))
pygame.display.set_caption('Snake Game by Steve')
clock = pygame.time.Clock()
The next
step is to initialize the fonts we are going to use in the game. Pygame has the
ability to access system fonts using the pygame. font.Sysfont function.
font_style = pygame.font.SysFont("bahnschrift", 25)
score_font = pygame.font.SysFont("comicsansms", 35)
In the function, we give the font name as a string followed by its size as an integer.
Methods
A couple of methods are required to make sure the game runs properly.
1. Score Method
We will need to display the score of
the player as they play the game. As always pygame has us sorted out. It’s just
a matter of writing down the inbuilt functions. First, we create a method called
Your_Score with the parameter score. We then use the font.render() function to
display the score in the game window. This creates a new Surface with the specified
text rendered on it. Pygame provides no way to directly draw text on an
existing Surface: instead, you must use Font.render() to create an image (Surface) of
the text, then blit this image onto another surface. To blit the text, we use dis. blit().
It takes in the value(what you want to be displayed on the surface) and the location
of the value. In our case, the location is point 0,0. You can change the locations
to see how it changes. Note: The location should within 0 to 600 for the width
and 0 to 400 for the height.
def Your_score(score):
value = score_font.render("Your Score: " + str(score), True, yellow)
dis.blit(value, [0, 0])
2. Snake Method
Next,
we need to draw the snake. It will be a rectangle that increases in length as
it ‘eats’. For this, we create an our_snake method. It has two parameters
snake_block and snake_list. The snak_list will be expounded in the gameloop
method. Inside the method, we loop the snake_list then we draw the snake using
pygame.draw.rect() function. It draws a rectangle with the format rect(surface, color, rect). The parameters are as follows
- surface to draw on
- color (or int or tuple(int, int, int, [int]))
-- color to draw with, the alpha value
is optional if using a tuple (RGB[A])
- rect -- rectangle to draw, position and
dimensions
- width (int)
def our_snake(snake_block, snake_list):
for x in snake_list:
pygame.draw.rect(dis, black, [x[0], x[1], snake_block, snake_block])
3. Message Method
This method takes the
score method format. We create the message method with two parameters, the
message and its color. In the blit function, the width and height are dived
into two to make sure that the message appears at the middle of the surface.
def message(msg, color):
message = font_style.render(msg, True, color)
dis.blit(message, [dis_width / 6, dis_height / 3])
4. Gameloop method
def gameLoop():
game_over = False
game_close = False
x1 = dis_width / 2
y1 = dis_height / 2
x1_change = 0
y1_change = 0
snake_List = []
Length_of_snake = 1
foodx = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0
foody = round(random.randrange(0, dis_height - snake_block) / 10.0) * 10.0
while not game_over:
while game_close == True:
dis.fill(blue)
message("You Lost! Press C-Play Again or Q-Quit", red)
Your_score(Length_of_snake - 1)
pygame.display.update()
for event in pygame.event.get():
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_q:
game_over = True
game_close = False
if event.key == pygame.K_c:
gameLoop()
for event in pygame.event.get():
if event.type == pygame.QUIT:
game_over = True
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_LEFT:
x1_change = -snake_block
y1_change = 0
elif event.key == pygame.K_RIGHT:
x1_change = snake_block
y1_change = 0
elif event.key == pygame.K_UP:
y1_change = -snake_block
x1_change = 0
elif event.key == pygame.K_DOWN:
y1_change = snake_block
x1_change = 0
if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0:
game_close = True
x1 += x1_change
y1 += y1_change
dis.fill(blue)
pygame.draw.rect(dis, green, [foodx, foody, snake_block, snake_block])
snake_Head = []
snake_Head.append(x1)
snake_Head.append(y1)
snake_List.append(snake_Head)
if len(snake_List) > Length_of_snake:
del snake_List[0]
for x in snake_List[:-1]:
if x == snake_Head:
game_close = True
our_snake(snake_block, snake_List)
Your_score(Length_of_snake - 1)
pygame.display.update()
if x1 == foodx and y1 == foody:
foodx = round(random.randrange(0, dis_width - snake_block) / 10.0) * 10.0
foody = round(random.randrange(0, dis_height - snake_block) / 10.0) * 10.0
Length_of_snake += 1
clock.tick(snake_speed)
pygame.quit()
quit()
This method contains the
functionality of the game. It is here that we program the snake to move,
increase in size after successful collision with the ‘food’ and end the game if
the player hits the walls. First, we initialize a couple of variables. The
snake_list is initialized in at this point.
We need to create the food particles hence the foodx and foody
variables. Next, we work with two while loops. The first one checks whether the
game is over and the second checks whether the game is still running. Inside
the second for loop, we set the background color of the game. We also work with
if statements checking for events within the game. The pygame.event.get ()
function allows us to use the keyboard in the gameplay. We loop through
various keys on the keyboard checking whether they have been pressed (KEYDOWN).
If a key has been pressed say the left arrow key, we program the snake to move
to the left-hand side of the surface. We do so by increasing the left
coordinate location of the snake. The same case applies to other respective
keys. It is also in this for loop that we check for successful collision of the
snake and the food. If a collision has occurred, we need to increase the snake
size, delete the food rectangle from that location and draw it somewhere else
in the game surface. The random module comes in handy at this point as it
allows us to randomly draw the food. We also call the other methods that we had
previously created here. If the player his the walls of the game surface, the
game stops and they asked whether they want to continue playing or to quit.
We finally end the game
creation by calling the game loop method.
gameLoop()
Useful links
The code on GitHub
Labels: Coding, Developers, Game development, Programming, Pygame, Python, Technology
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