Playdate Lua Basic Crank Example

-- Name this file `main.lua`. Your game can use multiple source files if you wish
-- (use the `import "myFilename"` command), but the simplest games can be written
-- with just `main.lua`.

-- You'll want to import these in just about every project you'll work on.

import "CoreLibs/object"
import "CoreLibs/graphics"
import "CoreLibs/sprites"
import "CoreLibs/timer"

-- Declaring this "gfx" shorthand will make your life easier. Instead of having
-- to preface all graphics calls with "playdate.graphics", just use "gfx."
-- Performance will be slightly enhanced, too.
-- NOTE: Because it's local, you'll have to do it in every .lua source file.

local gfx <const> = playdate.graphics

-- Here's our player sprite declaration. We'll scope it to this file because
-- several functions need to access it.

local playerSprite = nil

-- A function to set up our game environment.

function myGameSetUp()
    -- Create a dynamic player image
    local playerSize = 20 -- Size in pixels
    local playerImage = gfx.image.new(playerSize, playerSize)
    
    -- Draw on the player image
    gfx.pushContext(playerImage)
        -- Fill with white
        gfx.fillRect(0, 0, playerSize, playerSize)
        -- Draw a simple face
        gfx.setColor(gfx.kColorBlack)
        -- Eyes
        gfx.fillRect(5, 5, 2, 2)
        gfx.fillRect(playerSize - 7, 5, 2, 2)
        -- Mouth
        gfx.drawLine(5, 15, playerSize - 5, 15)
    gfx.popContext()
    
    playerSprite = gfx.sprite.new(playerImage)
    playerSprite:moveTo(200, 120)
    playerSprite:add()
    
    -- Create a dynamic background
    local backgroundWidth, backgroundHeight = 400, 240
    local backgroundImage = gfx.image.new(backgroundWidth, backgroundHeight)
    
    -- Draw on the background image
    gfx.pushContext(backgroundImage)
        -- Fill with a pattern
        gfx.setPattern({0xAA, 0x55, 0xAA, 0x55, 0xAA, 0x55, 0xAA, 0x55})
        gfx.fillRect(0, 0, backgroundWidth, backgroundHeight)
        
        -- Draw some objects
        gfx.setColor(gfx.kColorBlack)
        -- A few random circles
        for i = 1, 10 do
            local x = math.random(backgroundWidth)
            local y = math.random(backgroundHeight)
            local size = math.random(10, 30)
            gfx.drawCircleAtPoint(x, y, size)
        end
        
        -- Draw a ground line
        gfx.setLineWidth(3)
        gfx.drawLine(0, 200, backgroundWidth, 200)
    gfx.popContext()
    
    gfx.sprite.setBackgroundDrawingCallback(
        function(x, y, width, height)
            backgroundImage:draw(0, 0)
        end
    )
end

-- Now we'll call the function above to configure our game.
-- After this runs (it just runs once), nearly everything will be
-- controlled by the OS calling `playdate.update()` 30 times a second.

myGameSetUp()

-- `playdate.update()` is the heart of every Playdate game.
-- This function is called right before every frame is drawn onscreen.
-- Use this function to poll input, run game logic, and move sprites.

function playdate.update()
    -- Poll the d-pad and move our player accordingly.
    -- (There are multiple ways to read the d-pad; this is the simplest.)
    -- Note that it is possible for more than one of these directions
    -- to be pressed at once, if the user is pressing diagonally.

    if playdate.buttonIsPressed(playdate.kButtonUp) then
        playerSprite:moveBy(0, -2)
    end
    if playdate.buttonIsPressed(playdate.kButtonRight) then
        playerSprite:moveBy(2, 0)
    end
    if playdate.buttonIsPressed(playdate.kButtonDown) then
        playerSprite:moveBy(0, 2)
    end
    if playdate.buttonIsPressed(playdate.kButtonLeft) then
        playerSprite:moveBy(-2, 0)
    end

    -- Rotate the player sprite based on the crank position
    local crankPosition = playdate.getCrankPosition()
    print("Crank Position: " .. crankPosition);

    playerSprite:setRotation(crankPosition);
    
    -- Call the functions below in playdate.update() to draw sprites and keep
    -- timers updated. (We aren't using timers in this example, but in most
    -- average-complexity games, you will.)

    gfx.sprite.update()
    playdate.timer.updateTimers()
end