• Minimal Fennel Love2D Setup
• Phil's Modal Callbacks (PMC)
• Emacs Setup
• Project Structure
• Release Process

Minimal Fennel Love2D Setup

In a lead up to the annual Autumn Lisp Game Jam I thought I'd look into Phil Hegelberg's approach to last Aprils Jam, using love2d in concert with fennel. Phil outlines his approach on his blog.

The first step is to see how fennel works as a standalone execution environment, then slowly integrate some of the love2d API.

This repo contains the minimal viable setup to get started with Phil Hegelberg's game design process, plus some additional libraries.

PROJECT=project-name
git clone https://gitlab.com/alexjgriffith/min-love2d-fennel.git $PROJECT
cd $PROJECT
rm -rf .git

Phil's Modal Callbacks (PMC)

Phil Hegelberg's exo-encounter-667 is structured using a modal callback system. Each game state has a mode and each mode has a series of specific callbacks.

If you design your game as a series of states in a very simple state machine, for example start-screen, play and end, with unidirectional progression, you can easily separate the logic for each state into state/mode specific callbacks. As an example, in order to have state dependant rendering that differs between start-screen,play and end you could provide a draw callback for each of those states. Similarly if we need state dependent logic and keyboard input we could provide update and keyboard callbacks. As you iterate you can add and remove callbacks and states/modes as needed with very little friction.

Emacs Setup

Once you install the latest version of fennel-mode, you can run C-u M-x fennel-repl followed by love . to launch a repl.

Project Structure

The make process as-is will only compile the contents of the root folder and the lib/ folder+subfolders, so make sure to put your game files in either of those.

Specifically, every .fnl file needed at runtime needs to be situated in the root folder, and every file which is not a .lua or .fnl file needs to be put inside lib/.

In order to use macros, they have to be put in .fnl files inside lib/.

Release Process

Use make linux, make windows, or make mac to create executables for each platform, or make release to do all three. Make sure to read the makefile for more commands (and remember to edit your game data in it!)