Nintendo 3DS

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Revision as of 19:47, 30 November 2020 by Vovven (talk | contribs) (Add workaround for "namespace _3DS" issues in 3dsvars.sh script)
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3ds.png Nintendo 3DS Port
Latest Released Version 2.8.1
Supported Audio Options MP3, OGG, FLAC, Uncompressed
Additional Webpage(s) None
Maintainer(s) bgK
Packager(s) bgK
Forum Port Forum
Status Maintained
First Official Version 2.1.1

Installation

There are two possible formats to be used: 3DSX and CIA. The 3DSX format is considered more ethical because it does not make use of invalid title IDs, which get logged. It is also compatible with homebrew loading methods that do not involve CFW. The 3DSX format is exclusively used by the Homebrew Launcher and its derivatives. The CIA format can be installed directly to the 3DS home menu and can be launched using any CFW (Custom Firmware) of your choice.

Installing the Homebrew Launcher or any CFW is beyond the scope of this page.

3DSX installation

You need to merely extract the ScummVM 3DSX files to your SD card so that all files reside in the /3ds/scummvm/ directory. It can then be launched by Homebrew Launcher or a similar implementation.

CIA installation

The CIA format requires a DSP binary dump saved on your SD card as /3ds/dspfirm.cdc for proper audio support. You can search online to find software to dump this. Not having this file will cause many problems with games that need audio, sometimes even crashing, so this is NOT considered optional.

Using any CIA installation software (search elsewhere for that), you need to install the scummvm.cia file.

Controls

Default key mappings

The key mappings can be customized in the options dialog for the global mappings, and in the edit game dialog for per-game mappings. Per-game mappings overlay the global mappings, so if a button is bound to an action twice, the per-game mapping wins.

The default keymap is:

 Game Controller Mapping:
Button Action
Circle Pad Move the cursor
R + Circle Pad Slow Mouse
A Left mouse button
B Right mouse button
X Open virtual keyboard
Y ESC (skips cutscenes and such)
DPad Keypad "Cursor" Keys
L Trigger Toggle magnify mode on/off
R Trigger Toggle hover/drag modes
Start Open global main menu
Select Open 3DS config menu


Hover mode

When you use the touchscreen, you are simulating the mere moving of the mouse. You can click only with taps, meaning it is impossible to drag stuff or hold down a mouse button without using buttons mapped to right/left-click.

Drag mode

Every time you touch and release the touchscreen, you are simulating the click and release of the mouse buttons. At the moment, this is only a left-click.

Magnify mode

Due to the low resolutions of the 3DS's two screens (400x240 for the top, and 320x240 for the bottom), games that run at a higher resolution will inevitably lose some visual detail from being scaled down. This can result in situations where essential information is undiscernable, such as text. Magnify mode increases the scale factor of the top screen back to 1; the bottom screen remains unchanged. The touchscreen can then be used to change which part of the game display is being magnified. This can all be done even in situations where the cursor is disabled, such as during full-motion video (FMV) segments.

When activating magnify mode, touchscreen controls are automatically switched to hover mode; this is to reduce the risk of the user accidentally inputting a click when changing the magnified area via dragging the stylus. Clicking can still be done at will as in normal hover mode. Turning off magnify mode will revert controls back to what was being used previously (ex: if drag mode was in use prior to activating magnify mode, drag mode will be reactivated upon exiting magnify mode), as well as restore the top screen's previous scale factor.

Currently magnify mode can only be used when the following conditions are met:

  • In the 3DS config menu, "Use Screen" is set to "Both"
  • A game is currently being played
  • The horizontal and/or vertical resolution in-game is greater than that of the top screen

Magnify mode cannot be used in the Launcher menu.

Supported Games

While all the games should run on the 3DS (report if they do not), there are many games which are unplayable due to the lack of CPU speed on the 3DS. So if you play any games that run really slow, this is not considered a bug, but rather a hardware limitation.

The New 3DS console has much better performance, but there are still many newer and high-resolution games that cannot be played. A list of these unplayable games and game engines will eventually be listed here.

Compiling

Prerequisites

  • Latest version of devkitPro, which comes with devkitARM and libctru
  • citro3d thorugh devkitPro's pacman
  • Optional: You should compile third-party libraries for the 3ds (commonly referred to as portlibs in the devkitPRO community). Some games requires these to operate properly.

Compiling third-party libraries

It is strongly recommended that you use devkitPro's pacman in order to get the most recent portlibs for your build.

The following libraries can be downloaded with pacman:

Library Package
zlib 3ds-zlib
libpng 3ds-libpng
libjpeg 3ds-libjpeg-turbo
freetype2 3ds-freetype
libmad 3ds-libmad
libogg 3ds-libogg
tremor 3ds-libvorbisidec
flac 3ds-flac
curl 3ds-curl

At the moment of writing, the version of freetype2 packaged by devkitPro has an issue where it allocates too much data on the stack when ScummVM loads GUI themes. As a workaround, an older version can be used. Version 2.6.5 is known to work well. The instructions below can be used to compile it.

At the moment of writing, faad is not in the devkitPro 3DS pacman repository. It can be compiled by following the instructions in the section below, in case it cannot be found through pacman.

The following pacman packages are also recommended:

  • 3ds-dev
  • devkitpro-pkgbuild-helpers

Once you have the devkitpro-pkgbuild-helpers package, you should be able to find the following scripts in your /opt/devkitpro folder:

  • devkitarm.sh
  • 3dsvars.sh

Run them one after the other with `source` in order to setup your environment variables for cross-compiling: 

source /opt/devkitpro/devkitarm.sh
source /opt/devkitpro/3dsvars.sh

After that, you can download the libraries you want to cross compile, run any autoconf scripts that they may have, and then they can usually be built with the following steps from their source directory: 

mkdir -p $PORTLIBS
./configure --prefix=$PORTLIBS --host=arm-none-eabi --disable-shared --enable-static
make
make install

Most libraries used can be compiled with same commands and configuration flags.

Manually setting up the environment

In case you don't have the helpers package downloaded, you can use the following to set-up your environment variables.

It is assumed that you have these variables already set up. If not, then do so:

DEVKITPRO Your root devkitPro directory
DEVKITARM Your root devkitARM directory (probably same as $DEVKITPRO/devkitARM)
CTRULIB Your root libctru directory (probably same as $DEVKITPRO/libctru)

In the source directory of the library: 

export PORTLIBS=$DEVKITPRO/portlibs/3ds
export PATH=$DEVKITARM/bin:$PATH
export PKG_CONFIG_PATH=$PORTLIBS/lib/pkgconfig
export PKG_CONFIG_LIBDIR=$PORTLIBS/lib/pkgconfig
export CFLAGS="-g -march=armv6k -mtune=mpcore -mfloat-abi=hard -O2
                    -mword-relocations -ffunction-sections -fdata-sections"
export CPPFLAGS="-I$PORTLIBS/include -I$CTRULIB/include"
export LDFLAGS="-L$PORTLIBS/lib"

Compiling ScummVM

Do the following in a fresh terminal.

In case you get a "compiler not found" message, add the toolchain's executables to your PATH: 

export PATH=$DEVKITARM/bin:$PATH

In case you get an error about "namespace _3DS", edit the line in /opt/devkitpro/3dsvars.sh that reads 

export CPPFLAGS="-D_3DS -I${PORTLIBS_PREFIX}/include -I${DEVKITPRO}/libctru/include"

and remove the "-D_3DS" part so that it reads 

export CPPFLAGS="-I${PORTLIBS_PREFIX}/include -I${DEVKITPRO}/libctru/include"

Note: In more recent codebases of ScummVM, you may or may not need to set the following beforehand: 

export PKG_CONFIG_LIBDIR=$PORTLIBS/lib/pkgconfig

See above for $PORTLIBS.

ScummVM doesn't provide the CA certificates bundle required by the cloud synchronization features. You need to download it from the curl website: https://curl.haxx.se/ca/cacert.pem, and instruct the build system to package it in the binary: 

export DIST_3DS_EXTRA_FILES=/path/to/cacert.pem

The name of the file must be cacert.pem.

From the root of the scummvm repository: 

./configure --host=3ds --enable-plugins --default-dynamic
make

Additionally compile to specific formats to be used on the 3DS: 

make scummvm.3dsx
make scummvm.cia

Assuming everything was successful, you'll be able to find the binary files in the root of your scummvm folder.

Note: for the CIA format, you will need the makerom and bannertool tools which are not supplied with devkitPro.

Note: using dynamic plugins as suggested is required when building with most or all of the game engines enabled in order to keep the memory usage low and avoid stability issues.

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