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Version: 14 May 2024

Command Line Workflow

Overview

This section outlines the steps required to build Native applications (including sample applications) using a command line workflow for Magic Leap 2 devices and Application Simulator.

Prerequisites

  • Make sure you have properly installed everything listed in the Environment Setup, and have followed the instructions on downloading the ML Hub and the latest Magic Leap C SDK (MLSDK).

  • Python3 is required to run the build scripts located in the Magic Leap Samples folder.

    danger

    The MLSDK must be installed into a path without spaces.

  • Additionally, make sure you have OpenJDK-11 installed. You can download it from the Java Development Kit website.

  • Lastly, you must download the latest C-API Samples package from the Package Manager within ML Hub. On more information about the package manager, check the Package Manager guide.

The instructions below assume that all the content has been extracted to the {USER} directory.

Set up Environment Variables

After opening your preferred command line interface (CLI), you must set up the environment variables to point to the following folder locations. The directories in the code block below may be different for you depending on where you installed the tools.

  • ANDROID_HOME: Points to the top level Android SDK folder.
  • MLSDK: Points to the top level Magic Leap SDK folder.
  • JAVA_HOME: Points to the top level Java Virtual Machine folder.
set ANDROID_HOME=%USERPROFILE%\AppData\Local\Android\sdk

set MLSDK=%USERPROFILE%\MagicLeap\mlsdk\<mlsdk_version>

set JAVA_HOME=%USERPROFILE%\jdk-11

Notes on Building

  • All build.py scripts by default build for both device (aka ML2) and host (aka App Sim). If you only wish to build for host add --build host. If you only wish to build for device add --build device.
  • All build.py scripts by default build release config only. If you only wish to build debug config use --config debug. If you wish to build both debug and release configs use --config release debug.
  • For building a specific subset of applications please use the --area/-a parameter, e.x. for all apps use -a allprojects. To check all available subsets simply call python3 build.py --help and look for --area parameter explanation.
  • When building apps make sure that the MLSDK environment variable is pointing to the SDK install location.
  • All build.py scripts by default build both release and debug apps. If you only wish to build debug apps use --config debug. If you wish to build release apps --config release.
  • Make sure that that app_framework and apps are built for the same config (debug vs release).

Python build scripts are available for the C-API samples as well as the application framework upon which they are built. To run a full clean build using any of the build scripts you can use the following command:

python build.py --clean 
info
  • By default build.py assumes that Visual Studio 2019 version 17 is used. To select a different compiler, Visual Studio 2017 for example, add --msvc “Visual Studio 15 2017” to the command line.
  • Currently, the SDK supports Visual Studio up to version 17, 2019. If you are switching compilers make sure to do a full clean build by using the --clean parameter as shown below:
python build.py --clean --msvc "Visual Studio 17 2019"
info

If you receive errors that the Vulkan_LIBRARY is missing, make sure you have the Vulkan SDK installed on your machine.

Building the Application Framework

If you want to build applications that use the application framework, you must also build the Application Framework. In your CLI, change your working directory to the location of the app framework, usually under {USER}/MagicLeap/samples/c_api/app_framework. Then run the Python script found inside, build.py. Once compiled, the build script will collect all the build artifacts, headers, and CMake files in the output directory build/install.

cd %MLSDK%\samples\c_api\app_framework

python build.py --build device --config debug # build debug only for device

Then set the MAGICLEAP_APP_FRAMEWORK_ROOT environment variable to point to the top level App Framework install folder.

set MAGICLEAP_APP_FRAMEWORK_ROOT=%USERPROFILE%\MagicLeap\mlsdk\<mlsdk_folder_name>\samples\c_api\app_framework\build\install

Building the Sample Applications

You can either build all sample application APKs, or individual ones. To build all sample applications, change your working directory to the /samples directory, and run the build.py script inside.

cd %USERPROFILE%\MagicLeap\mlsdk\<mlsdk_folder_name>\samples\c_api\samples

python build.py --build device

Building Individual projects

Individual projects from within the sample folder can be built using the --project option as shown below, using the simple_gl_app project as an example. Built apks can be found in samples/out/sdk_device_samples/.

cd %USERPROFILE%\MagicLeap\mlsdk\<mlsdk_folder_name>\samples\c_api\samples
python build.py --build device --project simple_gl_app #note: no trailing slash

Magic Leap 2 is an AOSP device. Some of the sample applications have been converted and can be build individually using Gradle.

Manually Building Individual Samples

Applications that have a file called gradlew in their top directory can be built using the following script. You can find the output APK in the app/build/outputs/apk/ml2/ directory.

# For debug builds
gradlew assembleDebug
# For release builds
gradlew assembleRelease -Proot_path=<absolute path to parent directory of the samples, ending with a slash>
# For debug and release builds
gradlew build -Proot_path=<absolute path to parent directory of the samples, ending with a slash>
note

The --Proot_path parameter is needed for finding the certificates needed for signing release APKs.

If you are experiencing problems with Gradle, you can delete your build directory:

./gradlew clean
./gradlew assembleDebug

You can find the output APK in the app/build/outputs/apk/ml2/ directory.

note

Application Simulator is a tool that allows you to run your apps on your Windows PC or macOS without needing to build for the device. When you build apps for Application Simulator, you must launch them using the ZILauncher. To learn more about Application Simulator, check the Application Simulator Guide.

Generating Certificates for Signed Release APKs

For building signed release APKs, you need the following files in your scripts/ directory:

  • keystore.properties
  • mlsdk.keystore

Your scripts directory won’t have these files, so you need to create them yourself.

  1. keystore.properties has the following structure:
storePassword=<mlsdk.keystore password>
keyPassword=<key password>
keyAlias=<key alias>
storeFile=<path to mlsdk.keystore>
note

The <path to mlsdk.keystore> will be appended to the parent directory of samples/ directories like so: /home/user/Downloads/sdk_native_samples_src/<path to mlsdk.keystore>

  1. mlsdk.keystore file can be generated using either:
  • keytool command, supplied by Java JDK installation
  • Android Studio in Build > Generate Signed Bundle / APK... > APK > Key store path > Create new...