How to get started programming for the GAMEBOY!

Have you ever dreamed of becomming a game programmer? Today is your lucky day, becuase if you go through the following steps. I bet your can be making gameboy games in less than an hour, and that is if your modem is slow. By the time you finish reading this page you will have the basics that will enable you to build homebrewn games that will give give professional developers a run for their money. (well maybe not professional developers, but its a start!) Note this tutorial is rather dated. It covers the original gameboy, and not gameboy advance. For information about gameboy advance programming click here.

Step I : Emulation

Get into Emulation, it Rulez! You will definetly need to have a nice emulator for development. Even if you are lucky enough to have a copier and flash cartrige you will NOT want to transfer everytime you do a build. So find a good emulator. The two emulators I use are GB98, and NoCash. To find out the lasted in emulation news visit Zophar.

Step II : Be a Nerd, Be a Programmer

Learn C! You need to be able to program to write Gameboy software, if you need help visit CProgramming.com (which has lots of tutorials) If you are ambitious enough there are several excellent assemblers out there, but the Z80 opcodes are quite a bit different than the good old x86.

Step III : Downloading/Installing/Setting Up the Compiler

Get the GBDK (GameBoy Development Kit) by Pascal Felber. The download site is located at SourceForge.Net, you will need to go to this page http://sourceforge.net/project/showfiles.php?group_id=1249 and then scroll down to the Windows binaries. The file name of the write one is gbdk-2.95-3-win32.zip It is around 950k. It lets you build roms from C code. To install the GBDK you will need to unzip it so that the GBDK directory is right off the root (e.g. C:\GBDK) This is the most important step, without the compiler you can't MAKE GAMES!

Now you are probably wondering about the power of this compiler. So let's make a sample game, change your directory to C:\GBDK\EXAMPLES\GB\DSCAN. Now you will need to edit the MAKE.BAT in this directory, load it up and any editor (notepad) or dos edit, and add "..\" to the front of the two lines. It should look like this 

..\..\..\bin\lcc -Wa-l -c -o dscan.o dscan.c
..\..\..\bin\lcc -Wl-m -Wl-yp0x143=0x80 -o dscan.gb dscan.o
After you are done editing, run MAKE. When your done their should be a file dscan.gb. Load this into your emulator and watch the magic. You can really develop cool stuff with this compiler, eh? If you want to see more examples, look in the C:\GBDK\EXAMPLES\GB.

After seeing the power of the GBDK, you should add the following line to the end of your autoexec.bat to compile your programs. Type it in right NOW!

path %path%;C:\GBDK\BIN

Step IV : Your first ROM, Wahoo!

Write and compile the following program. Place it in a directory and give it the name NEW.C 
#include <gb/gb.h>
#include <stdio.h>

void main()
{
        printf("Welcome to GAMEBOY\nProgramming");
        printf("\nPress Start");
        waitpad(J_START);  // other keys are J_A, J_UP, J_SELECT, etc.
        printf("\nIsn't it easy!");
}
Compile it (make a ROM) by typing the following at the command line

lcc -o new.gb new.c
(You need to have added C:\GBDK\BIN to your path)

After that load up new.gb with an emulator and watch the magic. You just made your first Gameboy ROM!

Step V : Developing the Skill

Write some cool programs! Spend all your time writing games instead of playing them. For more tutorials on basic gameboy programming visit Gameboy Dev'rs. It is a great resource.

Step VI : Enter the GRAPHiCS

Get the Gameboy Tile Designer, and Map Builder. They will build the graphics and sprites you will use in your game. For help using these look through the GBDK samples. There is a lot of sample code out there.

Step VII : Keeping Up with the Scene

Now that your an accomplished gameboy programmer, it might be a good idea to keep up with the scene. Here are some of the most noteworthy sites out there.

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