This is a port of the UXN virtual machine for the GBA. UXN is a project created by the artist collective and research studio 100 rabbits. It can be used to write small graphical applications, tools and games. Programs written for UXN are distributed via bytecode compiled roms, akin to classic console emulators. For this project, uxn roms are embedded directly in the .gba rom.
Building from source
To build this software you need the devkitPro SDK. Once installed, you may need to modify the Makefile to ensure the path is correct, but should work with the default devikit installation methods on Linux and macOS.
DEVKITPRO := /opt/devkitpro DEVKITBIN := $(DEVKITPRO)/devkitARM/bin DEVKITTOOLS := $(DEVKITPRO)/tools/bin LIBGBA_DIR := $(DEVKITPRO)/libgba LIBGBA_SRC := $(DEVKITPRO)/libgba/include/ LIBGBA := $(LIBGBA_DIR)/lib/libgba.a LIBGBA += $(LIBGBA_DIR)/lib/libfat.a LIBGBA += $(LIBGBA_DIR)/lib/libmm.a
If everything is properly installed, you should be able to run
make to compile
the program into a
uxngba.gba rom. If you have
mgba-qt installed, you can
test it with:
To use a specific UXN compiled rom, you can pass it as the
make run UXN_ROM=roms/noodle.rom
The output .gba files will embed the rom used for installation. Different roms have different needs, such as the usage of different input methods or the desired audio quality. These options can be selected by defining the right macros on compile time as described below.
Input method order
Uxngba currently supports three different control schemes that can be cycled by
pressing the L or R buttons:
CONTROL_KEYBOARD. To select the order and available methods set the
CONTROL_METHODS macro on compile time. For example, noodle doesn't
make much use of the controller scheme, and we may want to use the mouse as the
default input method. This can be achieved with the following command:
make run UXN_ROM=roms/noodle.rom CONFIG="-DCONTROL_METHODS=CONTROL_MOUSE,CONTROL_KEYBOARD"
Audio processing can be computationally expensive and the GBA has limited
resources. uxngba supports 4 audio channel devices simultaneously, and depending
on the demands of the rest of the program, the audio quality can be increased or
decreased. By default, sounds will play on a 18157 Hz buffer, which offers
a good quality-performance compromise. A high quality and low-fi audio modes can
be selected by setting the
make run UXN_ROM=roms/audio.rom CONFIG="-DAUDIO_HIFI" or make run UXN_ROM=roms/audio.rom CONFIG="-DAUDIO_LOFI"
When writing text to the screen (for example using the console device) the text
will be drawn by default on the foreground layer. This can be controlled by
TEXT_MODE option to 0 for foreground mode or 1 for background
mode. The text layer can be omitted if using the TEXT_DISABLE macro.
make run CONFIG="-DTEXT_MODE=1" make run CONFIG="-DTEXT_DISABLE=1"
To enable profiling, the
PROF_ENABLE macro can be used. This will display the
cycle count for input handling (INPUT), loop uxn evaluation (EVAL), screen
buffer flip (FLIP) and audio mixing (MIX). If
PROF_ENABLE is set to 0, the
current frame numbers will be displayed, if set to 1, the maximum cycle count
for each section will be used instead. Enabling profiling can have a small
performance impact, so these numbers may not be 100% accurate, but should give
a good indication. Using
PROF_SHOW_Y we can control at which
tile the cycle count text will be located.
make run CONFIG="-DPROF_ENABLE=0 -DPROF_SHOW_Y=8 -DPROF_SHOW_X=8"