Playdate 11

Now that we have a player and two enemies, it feels like time to turn this little demo into a (not very good) game.

Some of the needed variables were already set up, but we need some functions to set up or reset the game state:

function resetGame()
    -- set map
    map:setTiles(myLevel, 15)

    -- start directions
    playerDirection = "n" -- none, or u/d/l/r
    enemyDirections = {"l","r"} -- an array
    gameScore = 0 -- everyone loves a score
    playerLives = 3 
    gameLive = true

    resetSprites()

    end

function resetSprites()
    -- set to initial positions
    playerSprite:changeState("r")
    playerSprite:moveTo( (topLeft + 16), 16 )  
    playerSprite:add() 
    enemySprites[1]:moveTo( (topLeft + (9*16)), (7*16) )  
    enemySprites[1]:add()
    enemySprites[2]:moveTo( (topLeft + (7*16)), (7*16) )  
    enemySprites[2]:add()  
    end

The resetSprites function is also used when the player loses a life, putting them back in their starting positions:

if checkCollisions() == true then
    enemySprites[1]:remove()
    enemySprites[2]:remove()
    playerSprite:remove()
    playerLives = playerLives - 1
    if (playerLives > 0 ) then
        resetSprites()
    else
        -- game over, do something?
        gameLive = false
    end
end

.. and we now have a game over state (gameLive is false), so need to handle that:

if gameLive == true then
        (etc)
else 
        -- in game over state
        if playdate.buttonIsPressed( playdate.kButtonA ) then
            resetGame();
        end

    end  

Finally, we need to put the score and lives up on screen. This should be easy using something like:

gfx.drawText('Score '..gameScore,280,60)

.. but I found that while I could draw text this way at the start of the program, all future updates seemed to be invisible.

I eventually figured out this is due to my using the Sprite tools – these were clearing the text off the screen. One way to handle this would be to turn the text into a sprite – I don’t yet know how – but a simpler one is to draw the text at the end of the “if game is live” loop, after the sprite work:

gfx.drawText('Score '..gameScore,280,60)

if gameLive == false then
    gfx.drawText('Game Over ',280,100)
    gfx.drawText('Press A',280,140)
else 
    gfx.drawText('Lives '..playerLives,280,100)
end   

Finally, loading in custom fonts. The code is simple:

-- Font from https://github.com/BleuLlama/Playdate-Stuff
local font = gfx.font.new('Font/diamond_12')
gfx.setFont(font)

.. but note that to import a font you need both the FNT file and its accompanying PNG file. I made the mistake of copying over just diamond_12.fnt, which didn’t work.

And with that.. it works? A very simple puck-man game in around 450 lines of Lua:

It’s not much of a game, but it’s a game. And along the way it taught me how to handle sprites, collisions, tile-map graphics, basic AI and text – not too bad.

Full Lua code here. All the previous posts in this series on Playdate programming from zero are here.