Snake Game Using Tkinter – Python
For many years, players all across the world have cherished the iconic video game Snake. The player controls a snake that crawls around the screen while attempting to consume food, avoiding obstacles or running into its own tail. It is a straightforward but addictive game. The snake lengthens each time it consumes food, and the player must control it as it moves through the game’s environment while attempting to consume as much food as they can without colliding. As the snake lengthens, the game’s difficulty increases because it gets more difficult to move around the screen. The Snake game is renowned for its straightforward gameplay features, which make it simple to learn but challenging to master. In this article, we are going to design the Snake game using Python‘s Tkinter library but before we start the game development, let’s see the rules of the game.
Rules of Snake Game
The rules of the Snake game vary depending on the specific version being played, but here are some common rules that are often followed:
- The player controls a snake that moves around the screen, trying to eat food while avoiding obstacles or running into its own tail.
- The snake grows longer each time it eats food.
- The player loses if the snake runs into an obstacle or its own tail.
- The player can control the direction the snake moves using arrow keys or a controller.
Step 1: Import all the required module.
Step 2: Set the dimensions of the game.
In this part of the program, we define the dimensions of the game.
Step 3: To create the snake in the game
The Snake class has a single method, __init__, which is a special method in Python classes that are run when an instance of the class is created. The __init__ method initializes the Snake object by setting its body_size attribute to the value of the BODY_SIZE constant, and creating two empty lists: coordinates and squares. It then populates the coordinates list with the BODY_SIZE number of [0, 0] elements, and uses a loop to create the BODY_SIZE number of rectangles on a canvas object using the create_rectangle method, with the upper-left corner at (x, y) and the lower-right corner at (x + SPACE_SIZE, y + SPACE_SIZE), and with the color specified by the SNAKE constant. The rectangles are appended to the squares list.
Step 4: Creating the food
The __init__ method initializes a Food object by generating two random integers, x and y, using the random.randint function. These integers are used to specify the upper-left corner of a food object, which is represented by an oval on a canvas. The oval has an upper-left corner at (x, y) and a lower-right corner at (x + SPACE_SIZE, y + SPACE_SIZE), and is filled with the color specified by the FOOD constant. The coordinates attribute of the Food object is set to a list containing x and y.
Step 5: Next Turn and collision checking
The function next_turn, takes two arguments: a snake object and a food object.
The function begins by getting the x and y coordinates of the head of the snake (the first element in the coordinates list of the snake object). It then uses an if statement to check the value of the direction variable, which is not defined in this code snippet. Depending on the value of direction, the x or y coordinate is incremented or decremented by the value of SPACE_SIZE.
The new x and y coordinates are then inserted at the beginning of the coordinates list of the snake object. A new rectangle is created on the canvas object at the new coordinates, with the upper-left corner at (x, y) and the lower-right corner at (x + SPACE_SIZE, y + SPACE_SIZE), and with the color specified by the SNAKE constant. The rectangle is then added to the squares list of the snake object.
The function then checks if the new head of the snake is at the same coordinates as the food object. If this is the case, the score is incremented, the text of the label object is updated to show the new score, the old food object is deleted from the canvas, and a new food object is created and displayed on the canvas. If the snake has not reached the food, the last element in the coordinates and squares lists of the snake object is removed.
Finally, the function calls the check_collisions function on the snake object. If this function returns True, the game_over function is called. If check_collisions returns False, the next_turn function is called again after a delay specified by the SPEED constant.
Step 6: Control the direction of the snake
This function change_direction takes a single argument: a string called new_direction.
The function begins by declaring the direction variable as global so that it can be modified within the function. It then uses an if statement to check the value of new_direction. If new_direction is ‘left’, the function checks if the current value of direction is not ‘right’. If this is the case, the value of direction is set to ‘left’. Similar checks are performed for the other possible values of new_direction. This function seems to be used to control the direction of a snake in a game or application. It prevents the snake from immediately reversing direction and allows it to change direction only if the new direction is not the opposite of the current direction.
Step 7: To check the collision of the snake
The function begins by getting the x and y coordinates of the head of the snake (the first element in the coordinates list of the snake object). It then checks if the x coordinate is less than zero or greater than or equal to the value of the WIDTH constant, or if the y coordinate is less than zero or greater than or equal to the value of the HEIGHT constant. If either of these conditions is true, the function returns True.
The function then uses a for loop to iterate over the elements of the coordinates list of the snake object, starting from the second element (snake.coordinates[1:]). For each element, the function checks if the x and y coordinates of the element are the same as the x and y coordinates of the head of the snake. If this is the case, the function returns True. If the loop completes without finding any collisions, the function returns False.
This function seems to be used to check for collisions between the snake and the edges of the display window or between different parts of the snake’s body. If a collision is detected, the function returns True, otherwise, it returns False.
Step 8: Main method
The code defines several functions, including game_over, change_direction, and next_turn, which were described in previous answers. It also defines several constants, such as WIDTH, HEIGHT, SPACE_SIZE, BODY_SIZE, SNAKE, FOOD, and BACKGROUND, which are used to configure the appearance and behavior of the game.
The program begins by creating a Tk object and setting the window title. It then initializes the score to zero and the direction of the snake to ‘down’. It creates a Label object to display the score and a Canvas object to display the game elements (the snake, food, etc.). The window is then centered on the screen and given keyboard bindings to allow the user to control the direction of the snake using the arrow keys.
The program then creates a Snake object and a Food object, and calls the next_turn function to start the game. The mainloop method is then called on the Tk object to start the GUI event loop and begin processing events.
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