My 5 Steps to Making a D&D Game Boy Game with C (2025)

Installation is straightforward. You can find the latest releases and setup instructions on the official GBDK-2020 GitHub page. They have guides for Windows, macOS, and Linux. The process generally involves downloading the release, unzipping it, and running a script to add it to your system's PATH. This lets you run the compiler commands from any terminal window.

For writing code, I strongly recommend Visual Studio Code. It’s free, powerful, and has excellent C/C++ support through extensions. A simple GBDK project folder will just contain your .c files and a Makefile to automate compilation. Don't worry, the example projects that come with GBDK provide a great template for this!

Step 3: Creating Your Art & Maps (The Pixel Dungeon)

Now for the fun part: creating the look of your world. But first, we must respect the Game Boy's limitations, which are also its greatest strengths.

• Resolution: 160x144 pixels. It's cozy!
• Colors: 4 shades of "green" (or gray, depending on the model).
• Graphics: Everything is built from 8x8 pixel tiles.

These constraints force you to be creative. Here are the tools you’ll need:

Aseprite for Pixel Art

Aseprite is the gold standard for pixel art, and it's perfect for this. The first thing you'll do is set up your 4-color Game Boy palette. A classic one to use is: #0f380f, #306230, #8bac0f, and #9bbc0f. Create your player sprite, your wall tiles, your floor tiles, your key—all as separate 8x8 pixel images (or larger sprites made of multiple 8x8 tiles).

png2asset for Conversion

Your C code can't just read a .png file. You need to convert it into a C array of tile data. GBDK-2020 includes a fantastic command-line tool called png2asset that does exactly this. It takes your PNG tileset and spits out a .c and .h file containing the raw tile data, ready to be included in your project. It's a massive time-saver.

Tiled for Map Making

Tiled is a free, open-source map editor. You’ll import your 8x8 tileset (the one you made in Aseprite) into Tiled. From there, you can "paint" your dungeon level tile by tile. When you're done, you can export the map data as a CSV or JSON file. Your C code will then read this data to know which tile to draw at each position on the background layer.

Step 4: Coding the Game Logic in C

With your assets ready, it's time to bring your game to life. This is where you'll write the rules of your world. At the center of it all is the game loop.

Your main C file, let's call it main.c, will look something like this at a high level:

#include <gb/gb.h>
#include <stdio.h>

// Include your converted tile and map data
#include "dungeon_tiles.h"
#include "dungeon_map.h"

void main() {
    // 1. Initialization: Load tiles and map
    set_bkg_data(0, TILE_COUNT, dungeon_tiles);
    set_bkg_tiles(0, 0, MAP_WIDTH, MAP_HEIGHT, dungeon_map);

    // Show the background
    SHOW_BKG;
    DISPLAY_ON;

    // 2. Game Loop: This runs forever
    while(1) {
        // Check for player input
        uint8_t joypad_state = joypad();

        if (joypad_state & J_LEFT) {
            // Move player left (update coordinates, move sprite)
        }
        if (joypad_state & J_RIGHT) {
            // Move player right
        }

        // Update game logic (e.g., check for collisions)

        // Wait for the screen to be ready for the next frame
        wait_vbl_done();
    }
}

Key Concepts in C

• Game Loop (while(1)): This is the beating heart of your game. It continuously checks for input, updates the game state, and redraws the screen.
• Input (joypad()): This GBDK function returns the current state of the D-pad and buttons. You use bitwise operators (like &) to check if a specific button is pressed.
• Background vs. Sprites: The Game Boy has two main graphics layers. The background is for static environments like your map. Sprites are for dynamic objects that move over the background, like the player, monsters, or items. You load their data separately and can move them around with functions like move_sprite().
• State Management: You'll need variables to keep track of everything. Simple integers for the player's X/Y coordinates (uint8_t player_x, player_y;) and booleans for inventory (UBYTE has_key = 0;) are a great start.

Start by just getting your background map to display. Then, add a sprite for the player. Then, make the sprite move with the D-pad. Each small victory will fuel you for the next step.

Step 5: Compiling, Testing, and Playing!

You’ve written the code. You’ve drawn the art. Now for the moment of truth. Compiling your game is surprisingly simple. If you've set up a Makefile (highly recommended, use the GBDK examples as a base), you can often just navigate to your project directory in a terminal and type:

make

GBDK will whir into action, compiling your C code and linking your assets. If all goes well, it will spit out a single, beautiful file: yourgame.gb. That's your ROM!

Testing with Emulators

You don't need a physical Game Boy to test your game. Emulators are your best friend for development. I recommend:

• SameBoy or BGB: Both are incredibly accurate emulators with powerful debugging tools. You can view memory, inspect tile data, and step through your code line by line. This is indispensable for squashing bugs.

Simply open the emulator and load your .gb file. Seeing your creation run for the first time is a feeling you won't forget.

Playing on Real Hardware

This is the ultimate prize. To play your game on an actual Game Boy, you'll need a flash cart, like an EverDrive or an EZ-Flash. These are special cartridges with an SD card slot. You copy your .gb file to the SD card, pop it into the flash cart, and put the cart in your Game Boy. Power it on, and you’re playing your very own game. It’s pure magic.

Your Adventure Begins

And there you have it—a five-step journey from idea to a playable Game Boy game. We've gone from a simple D&D concept to setting up a modern dev environment, creating pixel art, coding the core logic in C, and finally, playing it on an emulator or real hardware.

The key is to start small and celebrate every win. Don't get bogged down trying to build a massive world on your first attempt. Your epic D&D saga begins with a single tile and one line of code. Now go build it.

What simple D&D mechanic would you try to implement first? Let me know in the comments below!