StereoKit Template for CMake

This is a basic StereoKit template for C/C++ using CMake. It's straightforward and portable way to build native StereoKit apps on Linux, Windows, and Android! This template works quite well with VS Code, and following the prompts provided there can get you running pretty quickly. CMake can also be used to generate a Visual Studio solution, for those that prefer that workflow.

This template directly references and builds the StereoKit repository rather than using pre-built binaries, so this template could also be great for those that wish to fork and modify StereoKit's code!

Project Structure

• /src - Your application code.
• /Assets - Assets used by the app, textures, models, etc.
• /android - Android specific resources, build, and glue code.

Command line instructions

For those new to CMake, here's a quick example of how to compile and build this using the CLI! If something is going wrong, sometimes adding in a -v for verbose will give you some additional info you might not see from VS Code.

# From the project root directory

# Make a folder to build in
mkdir build

# Configure the build
cmake -B build
# Build and run
cmake --build build -j8 --target run

Linux

Linux users will need to install some pre-requisites for this template to compile.

sudo apt-get update
sudo apt-get install cmake libx11-dev libxfixes-dev libegl-dev libgbm-dev libfontconfig-dev

Android

This template also supports building and running APKs for Android! Setup for this is more complicated, but no code changes are required to make this work. This template provides some glue code in the /android folder to handle the lifecyle of your Android app, and more advanced projects may want to dig around in there!

If you don't care about Android, you can safely delete the /android folder of this repo. Nothing will break. Leaving it is fine too, it has no overhead.

Android Setup

To build for Android, you need a few SDKs! Android Studio has a good interface for grabbing these, and doubles as a nice tool for inspecting APKs.

Android SDKs

From Android Studio, go to Tools->SDK Manager.

• Under SDK Platforms, add API Level 32
• Under SDK Tools, add Android SDK Build-Tools 32.0.0
• Under SDK Tools, add NDK 25.2.9519653
• Make note of the Android SDK Location at the top of this panel.

SDK Platform version and SDK Tools version should match! Other versions may be fine, but pick matching versions. These instructions were tested with 32. Other NDK versions may work as well, but StereoKit is officially built with 25.2.9519653.

From the Android SDK location you noted, you'll need to suppy these variables as environment variables, or as configure parameters to CMake! This is how I would set these on windows via Powershell.

# Your path may vary

[Environment]::SetEnvironmentVariable('ANDROID_HOME',     'C:\Users\[user]\AppData\Local\Android\Sdk', 'User')
[Environment]::SetEnvironmentVariable('ANDROID_NDK_HOME', 'C:\Users\[user]\AppData\Local\Android\Sdk\ndk\25.2.9519653', 'User')

# Or just launch the GUI
rundll32 sysdm.cpl,EditEnvironmentVariables

Java SDK (JDK)

The JDK is installed alongside Android Studio, but may not be immediately accessible. In particular, packaging APKs requires javac and keytool from the JDK! These may be in PATH already, and if so, you're all set!

where javac
where keytool

But, if neither of these produces a result, you'll have to find the JDK's install directory! Mine was next to Android Studio. You can either add the JDK bin folder to path, or just set JDK's root folder to the JAVA_HOME variable that this template looks for.

# Your path may vary

# If you don't want to add to PATH
[Environment]::SetEnvironmentVariable('JAVA_HOME', 'C:\Program Files\Android\jdk\jdk-8.0.302.8-hotspot\jdk8u302-b08', 'User')

# Or add to path. It's always safest to add via GUI, but here's some powershell
# that'll do fine. Note that this is JDK\bin, and not JDK's root.
[Environment]::SetEnvironmentVariable('PATH', [System.Environment]::GetEnvironmentVariable('PATH', 'User') + ';' + 'C:\Program Files\Android\jdk\jdk-8.0.302.8-hotspot\jdk8u302-b08\bin', 'User')

# Or just launch the GUI
rundll32 sysdm.cpl,EditEnvironmentVariables

Ninja

This is a commonly used build tool that makes builds faster! In theory it's optional, but you may need to do some troubleshooting without it. Ninja's site is here, but you can install it quite easily via CLI:

• Windows: winget install Ninja-build.Ninja
• Linux (Ubuntu): apt-get install ninja-build

Android Build

# From the project root directory

# Make a folder to build in
mkdir build-android

# Configure the build, I'll often make a .bat file for this configure command
# just to make it easier to do!
cmake -B build-android ^
  -G Ninja ^
  -DCMAKE_ANDROID_NDK=%ANDROID_NDK_HOME% ^
  -DCMAKE_SYSTEM_NAME=Android ^
  -DCMAKE_SYSTEM_VERSION=32 ^
  -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a
# Same, but as a single line. Nicer if not using a .bat
cmake -B build-android -G Ninja -DCMAKE_ANDROID_NDK=%ANDROID_NDK_HOME% -DCMAKE_SYSTEM_NAME=Android -DCMAKE_SYSTEM_VERSION=32 -DCMAKE_ANDROID_ARCH_ABI=arm64-v8a
# Build an APK, install, and run it
cmake --build build-android -j8 --target run
# Or just build an APK
cmake --build build-android -j8 --target apk

Custom OpenXR Loader

If you need to use a custom OpenXR Loader for a non-conformant runtime such as Snapdragon Spaces, you can specify it with the OPENXR_CUSTOM_LOADER variable! See the CMakeLists.txt file for a commented out example. Note that you may need to do a full clean and rebuild if you're switching between the standard and a custom loader. It may be better to have a different build folder per-loader.