Pico Snake

Written in MicroPython for Raspberry Pi Pico and Pimoroni Pico Display

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Requirements

Hardware:

• Raspberry Pi Pico

• Pimoroni Pico Display

Software:

• Custom MicroPython image by Pimoroni (includes picodisplay library)

Classes

Game

• Manages the main game data and functionality.
  • Attributes include:
    • score
    • game states (e.g. title screen, playing, game over)
  • Methods include:
    • initialize level data
    • update game
    • get user input
    • draw game objects

Snake

• A singly-linked list to represent the Snake.
  • Attributes include:
    • pointer to "head" SnakeNode
    • current direction
  • Methods include:
    • push new head node
    • pop tail node
    • check if co-ordinate occupied by a SnakeNode
    • update direction
    • draw entire Snake
    • draw green line between two SnakeNodes

SnakeNode

• Single node in the Snake linked list.
  • Attributes:
    • position
    • direction
    • pointer to next node in list

Food

• Represents food for the Snake.
  • Attribute:
    • position
  • Methods:
    • draw food
    • reset position to random location (always ensures new position is not inside Snake or walls)

Level

• Represents the game arena.
  • Attribute:
    • array of wall positions
  • Methods:
    • load wall positions from txt file
    • draw walls
    • check for collisions with walls

Designing Levels

• Each level is a 20x11 grid of cells.
• Each cell in the grid can contain:
  • a SnakeNode
  • a piece of Food
  • a wall
  • nothing
• The "positions" of SnakeNodes, Food, and walls are defined in terms of this grid of cells:
  • ( 0, 0) top-left
  • (19, 0) top-right
  • ( 0, 10) bottom-left
  • (19, 10) bottom-right
• Levels are designed through a txt file:
  • Each line represents a row
  • Each character represents a cell
• The first 20 chars of the first 11 lines comprise the grid:
  • any chars or lines outside that range are currently ignored
  • extra parameters for each level could easily be added after line 11:
    • E.g. a target score to pass each level (currently hard-coded as 5 to simplify debugging)
  • The '0' char (zero) represents a wall
  • The ' ' char (space) represents an empty cell
    • Currently any char other than '0' represents an empty cell since all other chars are ignored
    • It would be relatively simple to add different wall types or level objects since they would just be defined with another char

For example, the file level-2.txt contains the following text:

00000          00000
0                  0
0                  0
0                  0
                    
                    
                    
0                  0
0                  0
0                  0
00000          00000

Which creates the following level:

NOTE: This image is blurry because it is a zoomed in photo of a very small screen. The actual Pico display module is surprising sharp and clear.