cellphone my mom had is carefully associated to the sport it had. Sure, the classical snake recreation, so easy but so addicting. I bear in mind taking part in this recreation on finish on my mom’s cellphone, shedding after which attempting repeatedly!
On this article, we are going to be taught to construct a easy Snake Recreation. We’ll use Python’s turtle module so as to generate this recreation. Notice that it is a newbies to intermediate degree Python tutorial, and expects the reader to be acquainted with Python fundamentals equivalent to features and loops, importing and accessing modules, and utilizing conditional statements. It additionally requires one to have a surface-level understanding of Object Oriented Programming, particularly creating objects cases from lessons. For the sake of simplicity, I’ll clarify every line of code. Let’s get began!
Understanding the Recreation
The classical Snake recreation entails a small snake with a plain background. Meals is supplied on the display screen. Because the snake eats the meals, it grows in dimension, and the rating will increase. As quickly because the snake collides with the boundary wall or itself, the sport ends, and one loses.
With a view to code this recreation in Python, we might want to deal with the next factors:
- Organising the Recreation Display screen – within the classical Snake recreation, the background is a boring neon yellow-green display screen
- Creating the Snake physique – the sport begins with a small black snake, which progressively will increase in dimension because it eats the meals
- Shifting the Snake – the snake can transfer within the 4 instructions: up, down, left, and proper by way of the arrow keys on the keyboard or corresponding buttons on the cellphone
- Creating the Meals – the meals for the snake seems at random areas on the display screen
- The Snake consuming the Meals – because the snake’s physique collides with the meals created, the rating is elevated in addition to the size of the snake, and new meals is generated randomly, and the sport continues.
- The Snake Colliding with itself or the Boundary Wall – if the snake’s physique collides with itself or the boundary of the sport display screen, the sport ends.
Allow us to begin coding.
Organising the Recreation Display screen
First issues first, we are going to create a brand new challenge in our IDE, let’s name it “Snake Recreation”. I’m utilizing PyCharm to code. Subsequent, we are going to create a brand new “snake recreation.py” file. To begin with, we are going to import the Turtle module, particularly its Display screen and Turtle lessons.
from turtle import Display screen, TurtleThe Turtle Module is a built-in Python bundle that enables one to attract shapes, strains, patterns, and animations on a display screen by way of code. The module works as if there’s a turtle with a brush on its again, and no matter you command it to go to, it’ll go there, thereby creating drawings. You possibly can ask the turtle to maneuver ahead, to show left by a sure angle, draw a circle and so on. The turtle will draw precisely that, and it’s a simple device to visualise one’s code. It helps practising variables, loops, features, coordinates, and fundamental animation logic with prompt visible outputs.
You possibly can try the Turtle Official Documentation right here.
As might be seen within the line of code above, now we have imported two components: Display screen and Turtle. These are lessons which can be outlined within the module. In Python, a category is a blueprint used to create objects. Turtle and Display screen are lessons which shall be used to create corresponding objects. These objects may have attributes (variables) and strategies (features) as outlined of their blueprint, with the availability of customization.
Allow us to first create the background for our recreation. We’ll use the Display screen class for this objective and customise it in response to our necessities. For reference, test the Display screen strategies from the official documentation right here.
#Organising the Recreation Display screen
display screen = Display screen()
display screen.setup(width=600, peak=600)
display screen.bgcolor("inexperienced yellow")
display screen.title("Snake Recreation")
display screen.tracer(0)
display screen.exitonclick()As might be seen within the code above, we first created the display screen object from the Display screen Class. Subsequent, now we have used the setup() technique of the Display screen class and set the width of the Recreation Display screen to 600×600. We’ve got personalized the background coloration to “inexperienced yellow” utilizing the bgcolor() technique. The title of the colour might be discovered by way of this hyperlink. I chosen the colour that carefully resembled the colour within the unique recreation. After that, now we have named the display screen “Snake Recreation” utilizing the title() technique. The tracer() technique from the Turtle class lets us management the animation. By giving an argument of “0”, now we have turned it off. This shall be higher understood after we create the snake and meals. Lastly, now we have used the exitonclick() technique to set the window to shut solely after we click on on it. In any other case, the window closes as quickly because it pops up and executes the entire code.
Operating the code above would output the next:
Creating the Snake Physique
As soon as now we have created the Recreation Display screen, the subsequent job is to create the snake. The snake can even be created utilizing the Turtle class. We’ll create 3 turtle objects that received’t resemble a turtle in any respect. Reasonably, they are going to be sq. segments, and when positioned collectively, will resemble a snake’s physique, identical to within the recreation. For this objective, we are going to use a for loop to create the three segments. Every section shall be positioned at a specified place. Allow us to code this:
#Creating the Snake
segments = []
starting_positions = [(0,0), (-20,0), (-40,0)]
for place in starting_positions:
new_segment = Turtle("sq.")
new_segment.coloration("black")
new_segment.penup()
new_segment.shapesize(1,1)
new_segment.goto(place)
segments.append(new_segment)
display screen.replace()Within the code above, we first created an empty checklist of segments. This checklist will include the snake segments. As soon as the snake segments are created, it’ll consist of three segments, and at any time when the snake eats its meals, the variety of segments will improve. We’ve got created a tuple starting_positions. This can include 3 positions specified by way of their x and y coordinates, and would be the positions the place the snake segments shall be created. We’ll create the primary section at (0,0), the second at (-20,0), and the third section at (-40,0). Utilizing the for loop, now we have created 3 segments from the variable new_segment as a turtle object, of sq. form and customary dimension 20×20. The arguments to shapesize() technique is given as 1×1 because it stretches the dimensions of the drawing cursor relative to its default 20×20 pixel dimension. The penup() technique permits us to cover the pen, and simply output the form of the turtle object. The goto() technique permits us to create the form ranging from that place. Lastly, now we have appended the newly created section to the empty checklist we created at first of this code block. On this approach, 2 extra segments shall be created as there are 2 extra positions within the starting_positions tuple.
In the long run, we are going to replace our display screen in order that it now reveals each the personalized display screen and the newly created snake. This would be the output:
Discover that now we have created the segments utilizing simply the for loop. As we go forward in our program, we might want to improve the snake’s segments because it eats the meals. With a view to make this addition handy to us, allow us to modify the code block and add a perform referred to as add_segments, to create the snake in addition to use it later when including segments to the snake when it eats the meals. This shall be a greater method to programming within the present situation:
#Creating the Snake
segments = []
starting_positions = [(0,0), (-20,0), (-40,0)]
#Including Segments Operate
def add_segments(place):
new_segment = Turtle("sq.")
new_segment.coloration("black")
new_segment.penup()
new_segment.goto(place)
segments.append(new_segment)
for place in starting_positions:
add_segments(place)
display screen.replace()Within the above code block, now we have finished precisely what we have been beforehand doing, that’s, creating the snake physique, besides that now we have used a Python perform to take action. We’ve got outlined a perform referred to as add_segments, whose objective is simply so as to add the segments to the snake’s physique, and the segments checklist. Furthermore, now’s the place the display screen’s tracer() technique comes to make use of. For those who remark out the display screen.tracer() line that we added within the begining you will note the animation of the snake’s physique being created one section at a time (and we don’t need that in our recreation!). This will higher be visualized by first importing the time module and utilizing the sleep() perform. The animation shall be extra seen.
import time
#Maintain the remainder of the code identical
for place in starting_positions:
add_segments(place)
time.sleep(1)
display screen.replace()Snake Motion
The subsequent job is to code the snake’s motion. To start with, allow us to simply make the snake transfer ahead. We’ll first create a variable game_is_on that shall be True so long as the sport is operating, and shall be switched to False as soon as we lose or the sport ends. This variable shall be used within the whereas loop. So long as the sport is on, the snake will proceed shifting, and we are going to solely be capable of change its course utilizing the arrow keys. That is going to be the a part of our program that can preserve the sport on.
Now comes the complicated half. To maneuver the snake ahead, we have to transfer all of its segments forward. The way in which to make the complete snake physique transfer ahead is by making every section, apart from the primary one, to maneuver to the one earlier than it. Which means that firstly, when the snake is barely 3 segments lengthy, section 3 will transfer to the place of section 2, and section 2 will transfer to the place of section 1, and section 1 will transfer ahead utilizing the turtle ahead() technique. This may be coded within the for loop, by giving it a beginning worth of the final factor of the checklist, which is the factor on the 2nd place (checklist components begin from 0, thus 0, 1, 2) when the snake is created (having 3 segments) or in any other case calculated because the size of the segments, minus 1. The for loop will finish at place 0, and as it’s shifting in reverse, we are going to give it a step dimension of -1. This entire situation is coded as under:
game_is_on = True
whereas game_is_on:
display screen.replace()
time.sleep(0.1)
for seg_num in vary(len(segments)-1, 0, -1):
new_x = segments[seg_num - 1].xcor()
new_y = segments[seg_num - 1].ycor()
segments[seg_num].goto(new_x, new_y)
segments[0].ahead(20)Discover that now we have added the display screen’s replace() technique, in addition to outlined the velocity of the snake utilizing the time module’s sleep() perform. By giving it an argument of 0.1, the snake segments will transfer ahead with a time delay of 0.1 seconds, and this velocity might be adjusted. If given an argument of 1, the time delay shall be 1 second, and the velocity of the snake shall be gradual. You possibly can experiment with the snake’s velocity by altering the values given to the sleep() perform.
The within of the for loop elaborates how the segments will transfer to the earlier segments’ place utilizing its coordinates. And on the finish, now we have the primary section of our snake shifting forward by 20 utilizing the turtle’s ahead() technique. Operating our code would output a shifting snake:
Controlling the Snake
Now that now we have seen tips on how to make the snake transfer, the subsequent factor is to manage the up/down/left/proper actions of the snake. For this, we are going to use the display screen listeners. We’ll code this system in order that on urgent the up, down, left, and proper keys, the snake will transfer accordingly by altering its head.
Another characteristic that we have to add, taking it from the unique snake recreation, is that when the snake is shifting left, it can not instantly flip proper, when it’s shifting up, it can’t instantly flip downwards. Briefly, the snake can not flip 180 levels from the place it’s shifting. Allow us to add this characteristic to our code. Ensure so as to add these strains of code earlier than the sport’s whereas loop we coded earlier.
#Controlling the Snake
display screen.hear()
def turn_up():
if segments[0].heading() != 270:
segments[0].setheading(90)
def turn_down():
if segments[0].heading() != 90:
segments[0].setheading(270)
def turn_left():
if segments[0].heading() != 0:
segments[0].setheading(180)
def turn_right():
if segments[0].heading() != 180:
segments[0].setheading(0)
display screen.onkey(turn_up, "Up")
display screen.onkey(turn_down, "Down")
display screen.onkey(turn_left, "Left")
display screen.onkey(turn_right, "Proper")As might be seen above, we first used the display screen’s hear() technique that lets us take heed to the display screen’s enter keys. Subsequent, now we have outlined features which shall be referred to as later within the display screen’s onkey() technique, which calls a perform primarily based on a keyboard key pressed. We’ve got outlined 4 features, every to show to a course aside from the exact opposite, utilizing the turtle’s technique setheading(). This technique units the top of the turtle, which is the primary section or section[0] to 0, 90, 180, or 270, that’s, proper, up, left, or down. The if conditional statements in every perform guarantee that the snake doesn’t flip in its wrong way, as we will see within the unique recreation.
Operating the whole code with this code block addition will allow us to transfer our snake:
Meals Creation
As soon as the snake has been created and programmed to maneuver utilizing the arrow keys, the subsequent job is to create the meals which the snake will eat and develop. This meals can even be created as a turtle object in a round form, in pink. We’ll set the shapesize to 0.5 so the meals is 10×10 pixels on the display screen. We’ve got additionally set the velocity() to “quickest” so the animation is quick, and there’s no delay in meals creation. Right here, we are going to import Python’s random module to create the meals at random positions on the sport display screen. We’ve got set the boundary of meals as -275 to 275 on each the x and y axes. That is in order that it’s simpler for the snake to eat its meals with out colliding with the outer display screen boundary.
Furthermore, at any time when the snake eats its meals, new meals must be generated. For this objective, we are going to outline a perform refresh() and generate new random coordinates the place the turtle object referred to as meals will transfer to. Try the code under:
#Creating the Meals
import random
meals = Turtle()
meals.coloration("pink")
meals.form("circle")
meals.penup()
meals.shapesize(stretch_len=0.5, stretch_wid=0.5)
meals.velocity("quickest")
random_x = random.randint(-275, 275)
random_y = random.randint(-275, 275)
meals.goto(random_x, random_y)
def refresh():
random_x = random.randint(-275, 275)
random_y = random.randint(-275, 275)
meals.goto(random_x, random_y)
Detect Collision with Meals
As soon as now we have created the meals, we now need to create a mechanism whereby the snake eats the meals. Which means that at any time when the snake touches the meals, the meals vanishes, and the snake grows by one section. We’ll code this situation such that at any time when the snake and meals are in shut proximity, in order that their distance is lower than 15, it means the snake has eaten the meals. We’ll make use of the turtle module’s distance() technique that calculates the gap between a turtle and a particular level or one other turtle object. If this distance is lower than 15 (by way of trial and error), it might imply the snake has touched or eaten its meals, and the meals ought to now transfer to a brand new location for recreation continuity. Therefore, we are going to now name the refresh() perform that we outlined earlier to maneuver the meals object to a brand new location. Consuming the meals ought to improve the snake’s dimension by a section. For this, we are going to outline a perform referred to as lengthen() exterior the whereas loop and name it contained in the if conditional assertion when the snake eats the meals.
#Snake extending
def lengthen():
add_segments(segments[-1].place())As might be seen, the lengthen() perform will add a brand new section to the final section of the snake’s physique. Now shifting on to the primary recreation’s loop:
game_is_on = True
whereas game_is_on:
...
#Retain the unique code right here
...
#Detect Collision with Meals
if segments[0].distance(meals) < 15:
refresh()
lengthen()
Scoreboard and Rating Updation
Subsequent is to create a scoreboard that might show the rating. To do that, we are going to code exterior the whereas loop. We’ll create this scoreboard and the rating as 2 turtle objects utilizing turtle’s write() technique, which permits us to show textual content on display screen. First, we are going to initialize a variable referred to as rating as 0. Because the snake eats its meals, the rating variable shall be elevated by 1 every time. Subsequent, we are going to create 2 turtle cases, scoreboard and my_score. The scoreboard object will show the textual content on display screen “Rating = “, whereas the my_score object will show the rating variable, which can change because the snake eats its meals. As might be seen within the code under, each of those turtle objects have been personalized for the display screen textual content show in response to the necessity.
#Creating the Scoreboard & Rating
rating = 0
scoreboard = Turtle()
scoreboard.coloration("black")
scoreboard.penup()
scoreboard.hideturtle()
scoreboard.goto(0,250)
scoreboard.write("Rating = ", True, align="heart", font=("Arial", 12, "regular"))
my_score = Turtle()
my_score.coloration("black")
my_score.penup()
my_score.hideturtle()
As soon as now we have created the above, we are going to now proceed so as to add the availability of fixing the core throughout the whereas loop of the sport, contained in the if conditional assertion when the snake collides with the meals. Examine the code under and replace the particular strains of code:
game_is_on = True
whereas game_is_on:
...
#Retain the unique code right here
...
#Detect Collision with Meals
if segments[0].distance(meals) < 20:
refresh()
lengthen()
rating = rating + 1
my_score.goto(40, 250)
my_score.clear()
my_score.write(rating, True, align="heart", font=("Arial", 12, "regular"))The next is displayed on the display screen after operating this system with the above additions:
Recreation Ending
When the sport ends, we have to inform the consumer that the sport is over, relatively than simply closing the show display screen. For this we are going to outline a perform and name it at any time when the sport ends: both by collision with a wall or by collision with tail. We’ll use the turtle object for this as effectively. That is the perform, and it will likely be referred to as when game_is_on variable turns to False.
#Recreation Over Pop Up
def game_over():
game_over = Turtle()
game_over.coloration("black")
game_over.penup()
game_over.hideturtle()
game_over.write("GAME OVER", True, align="heart", font=("Arial", 40, "regular"))
Detect Collision with Wall
One other situation of the sport’s continuity is to verify the snake doesn’t collide with the boundary wall of the display screen. With a view to code this, and realizing that the sport’s display screen is 600×600, we are going to take into account the boundary wall a sq. with its corners to be at these factors: (290, 290), (290, -290), (-290, -290) and (-290, 290). The wall detection block shall be throughout the recreation loop in a separate if conditional assertion as follows:
game_is_on = True
whereas game_is_on:
...
#Retain the unique code right here
...
# Detect Collision with Wall
if segments[0].xcor() > 290 or segments[0].xcor() < -290 or segments[0].ycor() > 290 or segments[0].ycor() < -290:
game_is_on = False
game_over()
Within the above strains of code, now we have accessed the x and y coordinates of the primary section of the snake and checked whether or not it falls inside or exterior of the boundary wall.
Detect Collision with Tail
Lastly, we are going to finish this program with one other situation of the sport, which is that if the snake’s head collides with itself, that’s, the primary section collides with every other section, the sport ends. We’ll use the for loop to code this situation:
game_is_on = True
whereas game_is_on:
...
#Retain the unique code right here
...
# Detect Tail Collision
for section in segments[1:]:
if segments[0].distance(section) < 10:
game_is_on = False
game_over()
When the sport ends, we have to inform the consumer that the sport is over, relatively than simply closing the show display screen. For this, we are going to name the game_over perform we outlined earlier.
Conclusion
On this tutorial, now we have efficiently carried out the snake recreation in Python. We’ve got used our understanding of Python fundamentals, equivalent to defining and calling features, utilizing lists and tuples, utilizing for and whereas loops in addition to conditional statements. We’ve got additionally carried out our fundamental understanding of Object Oriented Programming to create objects from a module’s lessons. When you’ve got any queries concerning any piece of code or a suggestion to make the code extra strong and environment friendly, be happy to remark and share your concepts. Till then, code, play, and problem your folks to the Snake Recreation you have got designed!
