Lua 0. Getting Started

• Introduction
• Debugging Locally
• Running On 32Blit
• Basics Of A 32Blit Lua Script

Introduction

Lua on the 32Blit is an application, like any other, with two key differences:

1. Instead of being a game in its own right, it understands and runs .lua scripts
2. It registers a file association with the 32Blit launcher so you can browse run .lua scripts right from the main menu

This introduction will teach you how to run 32Blit Lua files on your computer and on the 32Blit:

Debugging Locally

You don't strictly need a 32Blit for testing out your .lua scripts. You can build the Lua engine from source and run it right on your computer or grab the latest release for your platform and run a .lua file with the --launch_path argument like so:

./32blit_lua --launch_path script.lua

Running On 32Blit

You will need an SD card inserted in your 32Blit to save .lua files or resources.

For copying games over to your 32Blit you'll need the 32blit tools. These require Python 3 and you can install them with:

python3 -m pip install 32blit --user

You must also install 32blit_lua.blit onto your device so it can recognise and run Lua. Grab the latest release for the 32Blit (STM32), eg: 32blit-lua-v0.0.2-STM32.zip. Extract the file and use the 32Blit tool to install it:

32blit install 32blit_lua.blit

You should now be able to use the 32Blit tools to save Lua scripts, images and more to your device:

32blit install my_script.lua

This will save my_script.lua to the root of your SD card, in the main menu this is called "ROOT" in the list at the top, and you can navigate between "FLASH:" and "ROOT" with the left/right buttons on your 32Blit.

Navigate to your script and launch it with the right (pink) face button.

Basics Of A 32Blit Lua Script

Every Lua script on the 32Blit has some basic requirements and must define the following functions:

1. init - for setting things up when your game first launches
2. update - for updating the state of your game, world or physics
3. render - called at 50FPS, for drawing your game world to the screen

A basic Lua script might look something like this:

function init()
end

function render(time)
    screen.pen = Pen(20, 30, 40)
    screen.clear()

    screen.pen = Pen(255, 255, 255)
    screen.text("Hello World", minimal_font, Point(10, 50))
end

function update(time)
end

This code will display the text "Hello World". You can save it as helloworld.lua and run it on your computer with:

./32blit_lua --launch_path helloworld.lua

You should see something like this:

Or you can save it to your 32blit with:

32blit install helloworld.lua

And it will show up in the launcher like this: