PICO-8



Main Menu Cartridge



Follow along with the video to learn how to control game states for a main menu!


The video moves quickly so pause whenever you need.

The video doesn't explain everything, but this page does!


Make sure you understand why this code works or you won't be able to make your own game states later!

After you made this main menu, change it up! Try some of the challenges below to spark some ideas!





Challenges!

After following the lesson, take on some of these challenges to test your knowledge and skills!

1. Add your main character to the Main Menu.

2. Add a background scene to the Main Menu.

3. Add other options, like "Select a Character".

4. Add another Game State before starting the actual game, such as an Options Menu.

How to make a Main Menu!



Game Sprites!


What is a sprite?

Explanation of Code!


  • 1. Set up the Variables

      What is a variable?
      function _init()
          --add your variables here
      end
      

      By setting up your variables inside of the _init() function, you can easily reset your game by calling _init(), and the variables here have access to any custom functions you write. That might come in handy later so it's a good practice.


      --variables
      scene="menu"
      x=63
      y=63

      The first variable is named scene. Then the equals sign tells the game to remember it with whatever we write next. scene holds a word (technically called a "string") and that string is the name of the scene (technically called a "game state") that we want to run.


      The next variables are named x and y. Together these tell the game where the player character is positioned on the screen.


      x=63 and y=63 because the screen has 128 pixels from left-to-right and top-to-bottom (# 0-127), so the screen center is at (63,63)

      These are used to draw the player character in the center of the screen at the beginning of the game.






  • 2. Simple State Machine

      --main update and draw
      
      function _update()
          if scene=="menu" then
              update_menu()
          elseif scene=="game" then
              update_game()
          end
      end
      
      function _draw()
          if scene=="menu" then
              draw_menu()
          elseif scene=="game" then
              draw_game()
          end
      end


      _update() makes changes to the game 30 times every second.

      _draw() runs after _update and draws to the game screen 30 times every second.

      if scene=="menu" then checks the "scene" variable for which state should be active.


      You can do this for each game state that you want to create. Just add an elseif to the check for the other game states.


      update_menu()

      draw_menu()

      update_game()

      draw_game()

      These are going to be our custom functions that become what _update() and _draw() will run, that are specific to the game state, when it is active.






  • 3. Specific Update Functions

      --updates
      
      function update_menu()
          if btnp(❎) then
              scene="game"
          end
      end
      
      function update_game()
          if btn(⬅️) then x-=1 end
          if btn(➡️) then x+=1 end
          if btn(⬆️) then y-=1 end
          if btn(⬇️) then y+=1 end
      
          if btnp(❎) then
              scene="menu"
          end
      end


      function update_menu() creates a custom function for the specific updating of the Main Menu scene.

      if btnp(❎) then checks if the player pressed the X button and ignores if the player holds it down too long.

      scene="game" changes the "scene" variable so that the game state will change to the actual game scene.






      function update_game() creates a custom function for the specific updating of the Game scene.


      if btn(⬅️) then x-=1 end ... is the Simple Movement code.


      Then we use the same check as in update_menu() function for switching the game state back to the Main Menu, only for demonstration purposes.

      You would probably want to have a Game Over scene or a Win scene after your Game scene, and not just from a click of a button.






  • 4. Specific Draw Functions

      --draws
      
      function draw_menu()
          cls()
          print("press ❎ to start",30,63)
      end
      
      function draw_game()
          cls()
          spr(1,x,y)
      end


      function draw_menu() creates a custom function for the specific drawing of the Main Menu scene.

      cls() clears the screen.

      print("press ❎ to start",30,63) writes the words "press X to start" at position (30,63) which is about center.






      function draw_game() creates a custom function for the specific drawing of the Game scene.


      cls() clears the screen.


      spr(1,x,y) simply draws the sprite #1 at the coordinates (x,y) which change in the update_game() function based on the player's button presses.






  • Full Code!

      --initialize
      function _init()
          --variables
          scene="menu"
          x=63
          y=63
      end
      
      -->8
      --main update and draw
      
      function _update()
          if scene=="menu" then
              update_menu()
          elseif scene=="game" then
              update_game()
          end
      end
      
      function _draw()
          if scene=="menu" then
              draw_menu()
          elseif scene=="game" then
              draw_game()
          end
      end
      
      -->8
      --updates
      
      function update_menu()
          if btnp(❎) then
              scene="game"
          end
      end
      
      function update_game()
          if btn(⬅️) then x-=1 end
          if btn(➡️) then x+=1 end
          if btn(⬆️) then y-=1 end
          if btn(⬇️) then y+=1 end
      
          if btnp(❎) then
              scene="menu"
          end
      end
      
      -->8
      --draws
      
      function draw_menu()
          cls()
          print("press ❎ to start",30,63)
      end
      
      function draw_game()
          cls()
          spr(1,x,y)
      end
      

      -->8 is a new tab in Pico-8. They don't appear inside the Pico-8 code editor.


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