Compiling ScummVM/Android

Compiling ScummVM for Android

This page describes how to build Android packages from the ScummVM source tree.

While one can go through the process of manually installing and configuring the toolchains for the target Android architectures, as well as cross-compiling any third party libraries (again for each target architecture), currently the recommended method is to use a Docker container that can be built using scripts from our Dockerised Buildbot repository. This page will cover how to build ScummVM for the supported target Android architecture using the Docker container method.

However, one can still attempt the manual way of setting up the Android toolchain(s), without using Docker containers, by following the logic and commands in our scripts for building the Docker images. It should be noted that the process of manually setting up the toolchains is considerably easy if the developer does not need any of the cross-compiled third party libraries that some of the game engines or functionalities of ScummVM depend on.

Preparatory work

On a Linux 64bit distribution

This process requires running on a recent Linux 64bit distribution, eg. Ubuntu 16.04 LTS or higher (or equivalent). These instructions were tested on a host running Ubuntu x64 20.04 LTS.

Install the git package in order to clone the ScummVM source code repository and keep it up-to-date, and also some additional packages to build the Docker toolchain containers:

sudo apt-get update

sudo apt-get upgrade

sudo apt-get install git m4 make

Follow the instructions on the official Docker documentation page to install the Docker Engine on Linux. We tested with Docker Engine Community Edition 19.03.12, (build 48a66213fe) using containerd.io version 1.2.13 on Linux Ubuntu x64 20.04 LTS.

On Windows 10 (version 1904 or higher) using WSL2

Please, follow the instructions on the official Docker documentation page to install the Docker Engine on Windows 10 using WSL2. This process requires rebooting your PC at least a couple of times. The instructions also link to appropriate documentation on how to enable WSL on Windows and install a Linux distribution from the Windows Store. These instructions were tested with the Ubuntu 20.04 LTS app installed.

After enabling WSL2, and running Docker Desktop (with WSL integration), launch a bash shell for your installed Linux distribution by running the respective Windows app (here, Ubuntu 20.04 LTS). You can launch multiple bash shells by running the Linux distribution app multiple times.

From the Linux bash shell do:

sudo apt-get update

sudo apt-get upgrade

sudo apt-get install git m4 make

• Important note: The instructions below assume that you are running the commands from a Linux bash shell. If you're on Windows, please make sure you always have Docker Desktop up and running before launching your Linux bash shell(s).

Setting up the environment

In this step we will fetch the latest code from the ScummVM source code repository, and create a few additional folders and files that will help in the building process and/or improve its ease of use (eg. by maintaining the history of submitted commands).

From your Linux host shell do:

mkdir -p ~/Workspace

mkdir -p ~/Workspace/android-scummvm-bb/bshomes

touch ~/Workspace/android-scummvm-bb/.bash_history

sudo chmod o+rw ~/Workspace/android-scummvm-bb/.bash_history

Now clone the ScummVM repository:

cd ~/Workspace

git clone https://github.com/scummvm/scummvm.git

Also clone the ScummVM dockerized buildbot repository and build the Docker containers:

git clone https://github.com/scummvm/dockerized-bb.git ~/Workspace/android-scummvm-bb/dockerized-bb

cd ~/Workspace/android-scummvm-bb/dockerized-bb

make toolchains/android/pull

At this point the docker images command should return something like the following:

docker images

REPOSITORY                  TAG       IMAGE ID       CREATED             SIZE
toolchains/android          latest    2005faedc472   22 minutes ago      3.9GB
toolchains/android-common   latest    c726cca9065b   About an hour ago   30kB
toolchains/common           latest    c751ec410582   About an hour ago   24.7kB

• Important note: From time to time, you may need get updates from our Dockerized buildbot code (using git pull) and rebuild the toolchain containers, in order to make use of the latest improvements and any additional third party cross-compiled libraries.

Launch the Docker container

Now launch the Docker container shell:

docker run -v ~/Workspace/scummvm:/data/scummvm -v ~/Workspace/android-scummvm-bb/bshomes:/data/bshomes/android -v ~/Workspace/android-scummvm-bb/.bash_history:/root/.bash_history -w /data/scummvm -it toolchains/android /bin/bash

Compiling

Set the environment variables

The following commands are meant to be run from the Docker Container shell:

First, make sure that the required environment variables are set with the correct values:

export RO_ANDROID_ROOT=/opt/android \
ANDROID_EXTERNAL_ROOT=/data/bshomes/android \
HOST_TAG=linux-x86_64

Then run:

export ANDROID_NDK_ROOT=${RO_ANDROID_ROOT}/ndk \
ANDROID_TOOLCHAIN=${RO_ANDROID_ROOT}/ndk/toolchains/llvm/prebuilt/linux-x86_64 \
ANDROID_SDK_ROOT=${ANDROID_EXTERNAL_ROOT}/sdk \
ANDROID_SDK_HOME=${ANDROID_EXTERNAL_ROOT}/sdk-home \
GRADLE_USER_HOME=${ANDROID_EXTERNAL_ROOT}/gradle \
ANDROID_SDK_BTOOLS_VERSION=29.0.3

• Important note 1: The above command reflects the SDK build tools version installed by the container at the time of writing. This version string may need updating if the container is updated to set up a more recent version of the SDK build tools.
• Important note 2: Essentially, the set up of the SDK build tools path as an environmental variable, which is appended to the $PATH environemental variable below, is required only for running the apksigner command to sign a release build manually.

Additionally, run:

export ANDROID_SDK_TOOLS=${ANDROID_SDK_ROOT}/tools \
ANDROID_SDK_BTOOLS=${ANDROID_SDK_ROOT}/build-tools/${ANDROID_SDK_BTOOLS_VERSION} \
PATH=${ANDROID_SDK_TOOLS}:${ANDROID_SDK_BTOOLS}:${PATH} \
NDK_LOG=1 \
LC_ALL=C \
CCACHE_COMPRESS=1

Also, after setting up these variables, run the following command:

mkdir -p "${ANDROID_SDK_ROOT}" "${ANDROID_SDK_HOME}" "${GRADLE_USER_HOME}"

cp -R "${RO_ANDROID_ROOT}"/sdk/licenses "${ANDROID_SDK_ROOT}"/licenses

• Important note: The above command is only required to be run once, since it sets up some required folders and copies required SDK licenses to the external mounted folders (on the host Linux, outside the container itself)

Configuring and Compiling ScummVM

From your Linux host (ie. not from within the Container shell):

You should probably first make sure you are working with the latest ScummVM code. Please, run:

cd ~/Workspace/scummvm

git pull

From the Docker container shell:

Clean up any remnants folders from a previous build:

rm -rf android_project

rm -rf debug

rm -rf release

Configure and build ScummVM

Supported target architectures for the configure command (values for the --host switch parameter):

• android-arm64-v8a - for all new Android devices
• android-arm-v7a - for older Android devices
• android-x86 - ideal for emulator with 32bit images
• android-x86_64 - ideal for emulator with 64bit images

For a debug build

First run a make clean and configure command from inside the local scummvm repository folder (you should be in there by default after running the docker run command). Choose one of the following commands based on the target android architecture:

• Target android-arm64-v8a:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/aarch64-linux-android21-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/aarch64-linux-android/21/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/aarch64-linux-android/21" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-arm64-v8a --enable-debug

• Target android-arm-v7a:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/armv7a-linux-androideabi16-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/arm-linux-androideabi/16/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/arm-linux-androideabi/16" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-arm-v7a --enable-debug

• Target android-x86:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/i686-linux-android16-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/i686-linux-android/16/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/i686-linux-android/16" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-x86 --enable-debug

• Target android-x86_64:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/x86_64-linux-android21-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/x86_64-linux-android/21/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/x86_64-linux-android/21" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-x86_64 --enable-debug

Finally, in order to start the build process for all the above target architectures cases run:

make -j$(nproc) androiddistdebug

If successful, the debug apk file will be created inside a debug subfolder in the ScummVM repository folder. The default name will be ScummVM-debug.apk.

A debug build will be signed automatically by an auto-generated debug certificate. This certificate will be created by default inside a .android subfolder in your ${ANDROID_SDK_HOME} path, which here is the host path: ~/Workspace/android-scummvm-bb/bshomes/sdk-home/.android/. The debug keystore is named appropriately debug.keystore.

For instructions on how to create a debug signing certificate manually, if the developer wants to create it one their own for some reason, please refer to the Android Developers instructions here.

For a release build

First run a make clean and configure command from inside the local scummvm repository folder (you should be in there by default after running the docker run command). Choose one of the following commands based on the target android architecture:

• Target android-arm64-v8a:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/aarch64-linux-android21-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/aarch64-linux-android/21/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/aarch64-linux-android/21" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-arm64-v8a --disable-debug --enable-release

• Target android-arm-v7a:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/armv7a-linux-androideabi16-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/arm-linux-androideabi/16/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/arm-linux-androideabi/16" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-arm-v7a --disable-debug --enable-release

• Target android-x86:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/i686-linux-android16-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/i686-linux-android/16/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/i686-linux-android/16" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-x86 --disable-debug --enable-release

• Target android-x86_64:

CXX="ccache ${ANDROID_TOOLCHAIN}/bin/x86_64-linux-android21-clang++" PKG_CONFIG_LIBDIR="${ANDROID_TOOLCHAIN}/sysroot/usr/lib/x86_64-linux-android/21/pkgconfig" PATH=${PATH}:"${ANDROID_TOOLCHAIN}/sysroot/usr/bin/x86_64-linux-androidd/21" make clean; ./configure --enable-verbose-build --enable-all-engines --host=android-x86_64 --disable-debug --enable-release

Finally, in order to start the build process for all the above target architectures cases run:

make -j$(nproc) androiddistrelease

If successful, the release apk file will be created inside a release subfolder in the ScummVM repository folder.

Please note that a release build must be signed with a non-debug key in order to be installed on a Android device. In order to sign a release build, assuming you have created a release keystore named scummvm-release-key.keystore and have put it in your ${ANDROID_SDK_HOME} path on the host Linux (ie. here ~/Workspace/android-scummvm-bb/bshomes/sdk-home), you will need to run a command like the following:

apksigner sign --ks ${ANDROID_SDK_HOME}/scummvm-release-key.keystore --out release/scummvm-release-signed.apk release/ScummVM-release-unsigned.apk

Installing the apk on an Android Device

The quickest way to install a debug apk or a signed release apk on your Android Device is to use the Profile or Debug APK functionality of Android Studio.

• Important note: On Windows 10, you'll likely have Android Studio set up on the Windows host side. Hence, you will need to copy your apk from the Linux WSL2 environment to a Windows accessible folder. Since WSL2 mounts Windows folders by default under /mnt/, you could run from your Linux host (ie. not from inside the Docker Container) something similar to the following:

cp release/scummvm-release-signed.apk /mnt/c/scummvm-android-apks/

Android Studio setup

After the compiling process has concluded, one may find within the build directory (if used) a new directory called android-project. If following the above process, this folder will be inside the root folder of the locally cloned ScummVM source code repository.

This folder can be opened by Android Studio. C files are not yet available, but it is possible to edit the Java source files and debug both Java & native code (on an emulator or on a real device via an adb connection).

To enable debugging, after opening the android-project directory, please change Project configuration, under tab Debugger, and set field Debug type to Dual.

References

• Using the Docker images