GBDK Programming Sample

In the previous post, we checked out GBDK Programming Setup. The GBDK is a cross-platform development kit for sm83, z80 and 6502 based gaming consoles including the Nintendo Game Boy and Game Boy Color.

Using the GBDK, it is now possible to write game code using the C language rather than pure Z80 assembly. Therefore, we would like to extend this knowledge and checkout some code samples and homebrew games.

Let's check it out!

Software
Follow all instructions from the previous post: this documents how to setup all the pre-requisite software.
Note: ensure you have downloaded and installed the GBDK devkit and Small Device C Compiler [SDCC].

Examples
As per the previous post, after the GBDK has been downloaded, installed and setup, we should now checkout C:\gbdk\examples\gb to learn more about APIs available in the devkit. Replicate prior Hello World example.

Launch Visual Studio 2015. File | New | Project... | Visual C++ | Win32 | Win32 Project

Name:	Game
Location:	C:\apa_image
Create directory for solution	UNCHECKED

Copy over all original folders and files from the corresponding example. Copy from prior Hello World example the hidden .vscode folder and files. Copy also build.bat and align with source compile.bat file. Add relevant files to Visual Studio 2015. Press Ctrl+1 to build, link and run code similar to the prior Hello World example!

Launch Visual Studio Code. Open example folder. Set breakpoint in main.c. Press F5 to debug step thru code


Here is the complete list:

CUSTOM: apa_image  SOURCE: apa_image  CUSTOM: banks  SOURCE: banks  CUSTOM: bcd  SOURCE: bcd  CUSTOM: colorbar  SOURCE: colorbar  CUSTOM: comm  SOURCE: comm  CUSTOM: crash  SOURCE: crash  CUSTOM: dscan  SOURCE: dscan  CUSTOM: filltest  SOURCE: filltest  CUSTOM: galaxy  SOURCE: galaxy  CUSTOM: gb-dtmf  SOURCE: gb-dtmf  CUSTOM: gbcompress  SOURCE: gbcompress  CUSTOM: incbin  SOURCE: incbin  CUSTOM: irq  SOURCE: irq  CUSTOM: isr_vector  SOURCE: isr_vector  CUSTOM: large_map  SOURCE: large_map  CUSTOM: lcd_isr_wob  SOURCE: lcd_isr_wob

CUSTOM: linkerfile  SOURCE: linkerfile  CUSTOM: metasprites  SOURCE: metasprites  CUSTOM: paint  SOURCE: paint  CUSTOM: ram_function  SOURCE: ram_function  CUSTOM: rand  SOURCE: rand  CUSTOM: rpn  SOURCE: rpn  CUSTOM: scroller  SOURCE: scroller  CUSTOM: sgb_border  SOURCE: sgb_border  CUSTOM: sgb_multiplay  SOURCE: sgb_multiplay  CUSTOM: sgb_pong  SOURCE: sgb_pong  CUSTOM: sgb_sfx  SOURCE: sgb_sfx  CUSTOM: simple_physics  SOURCE: simple_physics  CUSTOM: sound  SOURCE: sound  CUSTOM: temp_minimal  SOURCE: temp_minimal  CUSTOM: temp_subfolder  SOURCE: temp_subfolder  CUSTOM: wav_sample  SOURCE: wav_sample

Samples
Gaming Monsters YouTube channel has many samples to teach how to develop your own GameBoy games:

Launch Visual Studio 2015. File | New | Project... | Visual C++ | Win32 | Win32 Project

Name:	Game
Location:	C:\SimpleSprites
Create directory for solution	UNCHECKED

Copy over all original folders and files from the corresponding example. Copy from prior Hello World example the hidden .vscode folder and files. Copy also build.bat and align with source's make.bat file. Add relevant files to Visual Studio 2015. Press Ctrl+1 to build, link and run code similar to the prior Hello World example!

Launch Visual Studio Code. Open example folder. Set breakpoint in main.c. Press F5 to debug step thru code


Here is the complete list:

CUSTOM: helloworld  SOURCE: helloworld  CUSTOM: simplesprites  SOURCE: simplesprites  CUSTOM: movesprites  SOURCE: movesprites  CUSTOM: background  SOURCE: background  CUSTOM: window  SOURCE: window  CUSTOM: sound  SOURCE: sound  CUSTOM: noise  SOURCE: noise  CUSTOM: simplejumping  SOURCE: simplejumping  CUSTOM: metasprites  SOURCE: metasprites  CUSTOM: spritecollision  SOURCE: spritecollision  CUSTOM: bkgdcollision  SOURCE: bkgdcollision

CUSTOM: splashscreens  SOURCE: splashscreens  CUSTOM: fadeeffects  SOURCE: fadeeffects  CUSTOM: keyboard  SOURCE: keyboard  CUSTOM: savename  SOURCE: savename  CUSTOM: colorsprites  SOURCE: colorsprites  CUSTOM: backgrounds  SOURCE: backgrounds  CUSTOM: makingmusic  SOURCE: makingmusic  CUSTOM: spritetricks  SOURCE: spritetricks  CUSTOM: scrolling  SOURCE: scrolling  CUSTOM: debugging  SOURCE: debugging  CUSTOM: platformer  SOURCE: platformer

Homebrew
Larold's Jubilant Junkyard is a website/blog/shop which focuses on creating digital products including game development projects and tutorials. The Nintendo GameBoy development tutorial series is very educational.

Follow Larold's Jubilant Junkyard YouTube video channel for additional GBDK 2020 information and content:

SCREEN resolution	20 x 18 tiles	160 x 144 pixels
BACKGROUND	32 x 32 tiles	256 x 256 pixels

Compiler flags

-Wm-yc	GameBoy Color compatible	NB: lowercase c
-Wm-yC	GameBoy Color only	NB: uppercase C
-Wm-ys	Super GameBoy compatible

GameBoy Color Tile Attributes

Bit 7	priority flag	0: tiles below sprites, 1: tiles above sprites
Bit 6	vertical flip	0: tiles normal, 1: flipped vertically
Bit 5	horizontal flip	0: tiles normal, 1: flipped horizontally
Bit 4	not used
Bit 3	character bank specification	0: tiles at bank0, 1: tiles at bank1
Bit 2	see bit 0
Bit 1	see bit 0
Bit 0	bits 0-2	indicate tile color palette assignment

Launch Visual Studio 2015. File | New | Project... | Visual C++ | Win32 | Win32 Project

Name:	Game
Location:	C:\AlleywayGameboy
Create directory for solution	UNCHECKED

Copy over all original folders and files from the corresponding example. Copy from prior Hello World example the hidden .vscode folder and files. Copy also build.bat and align with source's make.bat file. Add relevant files to Visual Studio 2015. Press Ctrl+1 to build, link and run code similar to the prior Hello World example!


NOTE: ensure that the GBDK header files are included for Intellisense: Right click project | Properties |
Configuration Properties | C/C++ | General | Additional Include Directories | %GBDK_WIN%/include; $(SolutionDir)/headers/gen; $(SolutionDir)/headers/main; %(AdditionalIncludeDirectories).

Here is the complete list:

CUSTOM: alleyway  SOURCE: alleyway  CUSTOM: flappy-bird  SOURCE: flappy-bird

CUSTOM: pacman  SOURCE: pacman  CUSTOM: space-invaders  SOURCE: space-invaders

Summary
Armed with all this knowledge, we are now in an excellent position to build complete video games for the Nintendo Game Boy and Game Boy Color. In the interim, we see the GameBoy Competition 2023 is here!