Move dead submodules in-tree

Signed-off-by: swurl <swurl@swurl.xyz>

externals/oboe/samples/SoundBoard/README.md

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+Soundboard
+==========
+Do you want to just jam with some digital tunes? Now you can!
+
+This sample demonstrates how to obtain the lowest latency and optimal computational throughput by:
+
+1) Leaving Oboe to choose the best default stream properties for the current device
+2) Setting performance mode to LowLatency
+3) Setting sharing mode to Exclusive
+4) Setting the buffer size to 2 bursts
+5) Using the `-Ofast` compiler optimization flag, even when building the `Debug` variant
+
+The [following article explaining how to debug CPU performance problems](https://medium.com/@donturner/debugging-audio-glitches-on-android-ed10782f9c64) may also be useful when looking at this code.
+
+Implementation details
+---
+The stream properties are left to Oboe as such the app must output audio data in a format which matches that of the stream. 
+
+Four different formats are supported: 
+
+|Channel count|Format|
+|-------------|------|
+|1 - Mono|16-bit int|
+|2 - Stereo|16-bit int|
+|1 - Mono|Float|
+|2 - Stereo|Float|
+
+The signal chain for mono streams is: 
+
+    SynthSound->Mixer
+
+For stereo chains a mono to stereo converter is added to the end of the chain: 
+
+    SynthSound->Mixer->MonoToStereo
+ 
+The compiler optimization flag `-Ofast` can be found in [CMakeLists.txt](CMakeLists.txt). 
+
+Each SynthSound is a series of 5 Oscillators, creating a pleasant sounding note when combined.
+
+The number of notes depends on the shape of the screen, with G3 being the first note.
+
+In order to determine whether a note should be played, MusicTileView demonstrates how to keep track of where each finger is.
+
+Images
+-----------
+![soundboard_image](soundboard_image.png)

externals/oboe/samples/SoundBoard/build.gradle

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+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+
+android {
+    defaultConfig {
+        applicationId "com.google.oboe.samples.soundboard"
+        minSdkVersion 21
+        targetSdkVersion 35
+        compileSdkVersion 35
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        externalNativeBuild {
+            cmake {
+                cppFlags "-std=c++17"
+                abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86', 'x86_64'
+            }
+        }
+    }
+    signingConfigs {
+        release {
+            storeFile new File("${System.properties['user.home']}/.android/debug.keystore")
+            storePassword 'android'
+            storeType "jks"
+            keyAlias 'androiddebugkey'
+            keyPassword 'android'
+        }
+    }
+    buildTypes {
+        release {
+            signingConfig signingConfigs.release
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+            debuggable false
+        }
+        debug {
+         debuggable true
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_18
+        targetCompatibility JavaVersion.VERSION_18
+    }
+    kotlinOptions {
+        jvmTarget = '18'
+    }
+    externalNativeBuild {
+        cmake {
+            path "src/main/cpp/CMakeLists.txt"
+        }
+    }
+    namespace 'com.google.oboe.samples.soundboard'
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation 'androidx.appcompat:appcompat:1.7.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.2.1'
+}

externals/oboe/samples/SoundBoard/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

externals/oboe/samples/SoundBoard/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme">
+        <activity android:name="com.google.oboe.samples.soundboard.MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

externals/oboe/samples/SoundBoard/src/main/cpp/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.4.1)
+
+
+### INCLUDE OBOE LIBRARY ###
+
+# Set the path to the Oboe library directory
+set (OBOE_DIR ../../../../..)
+
+# Add the Oboe library as a subproject. Since Oboe is an out-of-tree source library we must also
+# specify a binary directory
+add_subdirectory(${OBOE_DIR} ./oboe-bin)
+
+# Include the Oboe headers
+include_directories(${OBOE_DIR}/include ${OBOE_DIR}/samples/shared ${OBOE_DIR}/samples/debug-utils)
+
+
+### END OBOE INCLUDE SECTION ###
+
+add_library( soundboard SHARED
+        native-lib.cpp
+        SoundBoardEngine.cpp
+        )
+
+target_link_libraries(soundboard log oboe )
+target_link_options(soundboard PRIVATE "-Wl,-z,max-page-size=16384")
+
+# Enable optimization flags: if having problems with source level debugging,
+# disable -Ofast ( and debug ), re-enable it after done debugging.
+target_compile_options(soundboard PRIVATE -Wall -Werror -Ofast)

externals/oboe/samples/SoundBoard/src/main/cpp/SoundBoardEngine.cpp

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+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <memory>
+#include "SoundBoardEngine.h"
+
+/**
+ * Main audio engine for the SoundBoard sample. It is responsible for:
+ *
+ * - Creating the callback object which will be supplied when constructing the audio stream
+ * - Creating the playback stream, including setting the callback object
+ * - Creating `Synth` which will render the audio inside the callback
+ * - Starting the playback stream
+ * - Restarting the playback stream when `restart()` is called by the callback object
+ *
+ * @param numSignals
+ */
+SoundBoardEngine::SoundBoardEngine(int32_t numSignals) {
+    createCallback(numSignals);
+}
+
+SoundBoardEngine::~SoundBoardEngine() {
+    if (mStream) {
+        LOGE("SoundBoardEngine destructor was called without calling stop()."
+             "Please call stop() to ensure stream resources are not leaked.");
+        stop();
+    }
+}
+
+void SoundBoardEngine::noteOff(int32_t noteIndex) {
+    mSynth->noteOff(noteIndex);
+}
+
+void SoundBoardEngine::noteOn(int32_t noteIndex) {
+    mSynth->noteOn(noteIndex);
+}
+
+void SoundBoardEngine::tap(bool isDown) {
+    mSynth->tap(isDown);
+}
+
+void SoundBoardEngine::restart() {
+    stop();
+    start();
+}
+// Create the playback stream
+oboe::Result SoundBoardEngine::createPlaybackStream() {
+    oboe::AudioStreamBuilder builder;
+    return builder.setSharingMode(oboe::SharingMode::Exclusive)
+            ->setPerformanceMode(oboe::PerformanceMode::LowLatency)
+            ->setFormat(oboe::AudioFormat::Float)
+            ->setDataCallback(mDataCallback)
+            ->setErrorCallback(mErrorCallback)
+            ->openStream(mStream);
+}
+
+// Create the callback and set its thread affinity to the supplied CPU core IDs
+void SoundBoardEngine::createCallback(int32_t numSignals){
+
+    mDataCallback = std::make_shared<DefaultDataCallback>();
+
+    // Create the error callback, we supply ourselves as the parent so that we can restart the stream
+    // when it's disconnected
+    mErrorCallback = std::make_shared<DefaultErrorCallback>(*this);
+
+    mNumSignals = numSignals;
+}
+
+bool SoundBoardEngine::start() {
+    // It is possible for a stream's device to become disconnected during stream open or between
+    // stream open and stream start.
+    // If the stream fails to start, close the old stream and try again.
+    bool didStart = false;
+    int tryCount = 0;
+    do {
+        if (tryCount > 0) {
+            usleep(20 * 1000); // Sleep between tries to give the system time to settle.
+        }
+        didStart = attemptStart();
+    } while (!didStart && tryCount++ < 3);
+    if (!didStart) {
+        LOGE("Failed at starting the stream");
+    }
+    return didStart;
+}
+
+bool SoundBoardEngine::attemptStart() {
+    auto result = createPlaybackStream();
+
+    if (result == Result::OK) {
+        // Create our synthesizer audio source using the properties of the stream
+        mSynth = Synth::create(mStream->getSampleRate(), mStream->getChannelCount(), mNumSignals);
+        mDataCallback->reset();
+        mDataCallback->setSource(std::dynamic_pointer_cast<IRenderableAudio>(mSynth));
+        result = mStream->start();
+        if (result == Result::OK) {
+            return true;
+        } else {
+            LOGW("Failed attempt at starting the playback stream. Error: %s", convertToText(result));
+            return false;
+        }
+    } else {
+        LOGW("Failed attempt at creating the playback stream. Error: %s", convertToText(result));
+        return false;
+    }
+}
+
+bool SoundBoardEngine::stop() {
+    if(mStream && mStream->getState() != oboe::StreamState::Closed) {
+        mStream->stop();
+        mStream->close();
+    }
+    mStream.reset();
+    return true;
+}
+

externals/oboe/samples/SoundBoard/src/main/cpp/SoundBoardEngine.h

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+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SOUNDBOARD_ENGINE_H
+#define SOUNDBOARD_ENGINE_H
+
+
+#include <oboe/Oboe.h>
+#include <vector>
+
+#include "Synth.h"
+#include <DefaultDataCallback.h>
+#include <TappableAudioSource.h>
+#include <IRestartable.h>
+#include <DefaultErrorCallback.h>
+
+using namespace oboe;
+
+class SoundBoardEngine : public IRestartable {
+
+public:
+    SoundBoardEngine(int32_t numSignals);
+
+    virtual ~SoundBoardEngine();
+
+    void noteOff(int32_t noteIndex);
+
+    void noteOn(int32_t noteIndex);
+
+    void tap(bool isDown);
+
+    // from IRestartable
+    virtual void restart() override;
+
+    bool start();
+    bool stop();
+
+private:
+    int32_t mNumSignals;
+
+    std::shared_ptr<AudioStream> mStream;
+    std::shared_ptr<Synth> mSynth;
+    std::shared_ptr<DefaultDataCallback> mDataCallback;
+    std::shared_ptr<DefaultErrorCallback> mErrorCallback;
+
+    bool attemptStart();
+    oboe::Result createPlaybackStream();
+    void createCallback(int32_t numSignals);
+};
+
+
+#endif //SOUNDBOARD_ENGINE_H

externals/oboe/samples/SoundBoard/src/main/cpp/Synth.h

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+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SOUNDBOARD_SYNTH_H
+#define SOUNDBOARD_SYNTH_H
+
+#include <array>
+#include <TappableAudioSource.h>
+
+#include <SynthSound.h>
+#include <Mixer.h>
+#include <MonoToStereo.h>
+
+constexpr float kOscBaseFrequency = 196.00; // Start at G3
+constexpr float kOscFrequencyMultiplier = 1.05946309436;
+constexpr float kOscBaseAmplitude = 0.20;
+constexpr float kOscAmplitudeMultiplier = 0.96;
+
+class Synth : public IRenderableAudio, public ITappable {
+public:
+    static ::std::shared_ptr<Synth> create(const int32_t sampleRate, const int32_t channelCount, const int32_t numSignals) {
+        return ::std::make_shared<Synth>(sampleRate, channelCount, numSignals);
+    }
+
+    Synth(const int32_t sampleRate, const int32_t channelCount, const int32_t numSignals) {
+        mNumSignals = numSignals;
+        mOscs = std::make_unique<SynthSound[]>(numSignals);
+        float curFrequency = kOscBaseFrequency;
+        float curAmplitude = kOscBaseAmplitude;
+        for (int i = 0; i < numSignals; ++i) {
+            mOscs[i].setSampleRate(sampleRate);
+            mOscs[i].setFrequency(curFrequency);
+            curFrequency *= kOscFrequencyMultiplier;
+            mOscs[i].setAmplitude(curAmplitude);
+            curAmplitude *= kOscAmplitudeMultiplier;
+            mMixer.addTrack(&mOscs[i]);
+        }
+
+        if (channelCount == oboe::ChannelCount::Stereo) {
+            mOutputStage =  &mConverter;
+        } else {
+            mOutputStage = &mMixer;
+        }
+    }
+
+    void noteOff(int32_t noteIndex) {
+        mOscs[noteIndex].noteOff();
+    }
+
+    void noteOn(int32_t noteIndex) {
+        mOscs[noteIndex].noteOn();
+    }
+
+    void tap(bool isOn) override {
+        for (int i = 0; i < mNumSignals; i++) {
+            if (isOn) {
+                mOscs[i].noteOn();
+            } else {
+                mOscs[i].noteOff();
+            }
+        }
+    };
+
+    // From IRenderableAudio
+    void renderAudio(float *audioData, int32_t numFrames) override {
+        mOutputStage->renderAudio(audioData, numFrames);
+    };
+
+    virtual ~Synth() {
+    }
+private:
+    // Rendering objects
+    int32_t mNumSignals;
+    std::unique_ptr<SynthSound[]> mOscs;
+    Mixer mMixer;
+    MonoToStereo mConverter = MonoToStereo(&mMixer);
+    IRenderableAudio *mOutputStage; // This will point to either the mixer or converter, so it needs to be raw
+};
+
+
+#endif //SOUNDBOARD_SYNTH_H

externals/oboe/samples/SoundBoard/src/main/cpp/native-lib.cpp

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+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <jni.h>
+#include <string>
+#include <vector>
+
+#include "SoundBoardEngine.h"
+
+extern "C" {
+/**
+ * Start the audio engine
+ *
+ * @param env
+ * @param instance
+ * @param jCpuIds - CPU core IDs which the audio process should affine to
+ * @return a pointer to the audio engine. This should be passed to other methods
+ */
+JNIEXPORT jlong JNICALL
+Java_com_google_oboe_samples_soundboard_MainActivity_startEngine(JNIEnv *env, jobject /*unused*/,
+         jint jNumSignals) {
+    LOGD("numSignals : %d", static_cast<int>(jNumSignals));
+    SoundBoardEngine  *engine = new SoundBoardEngine(jNumSignals);
+
+    if (!engine->start()) {
+        LOGE("Failed to start SoundBoard Engine");
+        delete engine;
+        engine = nullptr;
+    } else  {
+        LOGD("Engine Started");
+    }
+    return reinterpret_cast<jlong>(engine);
+}
+
+JNIEXPORT void JNICALL
+Java_com_google_oboe_samples_soundboard_MainActivity_stopEngine(JNIEnv *env, jobject instance,
+        jlong jEngineHandle) {
+    auto engine = reinterpret_cast<SoundBoardEngine*>(jEngineHandle);
+    if (engine) {
+        engine->stop();
+        delete engine;
+    } else {
+        LOGD("Engine invalid, call startEngine() to create");
+    }
+}
+
+JNIEXPORT void JNICALL
+Java_com_google_oboe_samples_soundboard_MainActivity_native_1setDefaultStreamValues(JNIEnv *env,
+                                                                            jclass type,
+                                                                            jint sampleRate,
+                                                                            jint framesPerBurst) {
+    oboe::DefaultStreamValues::SampleRate = (int32_t) sampleRate;
+    oboe::DefaultStreamValues::FramesPerBurst = (int32_t) framesPerBurst;
+}
+
+JNIEXPORT void JNICALL
+Java_com_google_oboe_samples_soundboard_NoteListener_noteOff(JNIEnv *env, jobject thiz,
+                                                         jlong engine_handle, jint noteIndex) {
+    auto *engine = reinterpret_cast<SoundBoardEngine*>(engine_handle);
+    if (engine) {
+        engine->noteOff(noteIndex);
+    } else {
+        LOGE("Engine handle is invalid, call createEngine() to create a new one");
+    }
+}
+
+JNIEXPORT void JNICALL
+Java_com_google_oboe_samples_soundboard_NoteListener_noteOn(JNIEnv *env, jobject thiz,
+                                                         jlong engine_handle, jint noteIndex) {
+    auto *engine = reinterpret_cast<SoundBoardEngine*>(engine_handle);
+    if (engine) {
+        engine->noteOn(noteIndex);
+    } else {
+        LOGE("Engine handle is invalid, call createEngine() to create a new one");
+    }
+}
+
+} // extern "C"

externals/oboe/samples/SoundBoard/src/main/kotlin/com/google/oboe/samples/soundboard/MainActivity.kt

@@ -0,0 +1,152 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.oboe.samples.soundboard
+
+import android.app.Activity
+import android.content.Context
+import android.content.res.Configuration
+import android.graphics.Point
+import android.graphics.Rect
+import android.media.AudioManager
+import android.os.Build
+import android.os.Bundle
+import android.view.WindowInsets
+import android.view.WindowManager
+import androidx.annotation.RequiresApi
+import androidx.appcompat.app.AppCompatActivity
+import kotlin.math.min
+
+class MainActivity : AppCompatActivity() {
+    private external fun startEngine(numSignals: Int): Long
+    private external fun stopEngine(engineHandle: Long)
+    private external fun native_setDefaultStreamValues(sampleRate: Int, framesPerBurst: Int)
+
+    companion object {
+        private const val DIMENSION_MIN_SIZE = 6
+        private const val DIMENSION_MAX_SIZE = 8
+        private var mNumColumns : Int = 0;
+        private var mNumRows : Int = 0;
+        private var mTiles = ArrayList<Rect>()
+        private var mBorders = ArrayList<Rect>()
+
+        private var mEngineHandle: Long = 0
+
+        // Used to load the 'native-lib' library on application startup.
+        init {
+            System.loadLibrary("soundboard")
+        }
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_main)
+    }
+
+    override fun onResume() {
+        super.onResume()
+        setup()
+    }
+
+    override fun onPause() {
+        stopEngine(mEngineHandle)
+        super.onPause()
+    }
+
+    private fun setup() {
+        setDefaultStreamValues(this)
+        calculateAndSetRectangles(this)
+        mEngineHandle = startEngine(mNumRows * mNumColumns)
+        createMusicTiles(this)
+    }
+
+    private fun setDefaultStreamValues(context: Context) {
+        val myAudioMgr = context.getSystemService(AUDIO_SERVICE) as AudioManager
+        val sampleRateStr = myAudioMgr.getProperty(AudioManager.PROPERTY_OUTPUT_SAMPLE_RATE)
+        val defaultSampleRate = sampleRateStr.toInt()
+        val framesPerBurstStr =
+            myAudioMgr.getProperty(AudioManager.PROPERTY_OUTPUT_FRAMES_PER_BUFFER)
+        val defaultFramesPerBurst = framesPerBurstStr.toInt()
+        native_setDefaultStreamValues(defaultSampleRate, defaultFramesPerBurst)
+    }
+
+    private fun calculateAndSetRectangles(context: Context) {
+        val windowManager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
+        val display = windowManager.defaultDisplay
+        val size = Point()
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            val windowMetrics = windowManager.currentWindowMetrics
+            val windowInsets = windowMetrics.windowInsets
+            val insets = windowInsets.getInsetsIgnoringVisibility(
+                    WindowInsets.Type.navigationBars() or WindowInsets.Type.statusBars())
+            val width = windowMetrics.bounds.width() - insets.left - insets.right
+            val height = windowMetrics.bounds.height() - insets.top - insets.bottom
+            size.set(width, height)
+        } else {
+            display.getSize(size) // Use getSize to exclude navigation bar if visible
+        }
+
+        val width = size.x
+        val height = size.y
+
+        if (height > width) {
+            mNumColumns = DIMENSION_MIN_SIZE
+            mNumRows = min(DIMENSION_MIN_SIZE * height / width, DIMENSION_MAX_SIZE)
+        } else {
+            mNumRows = DIMENSION_MIN_SIZE
+            mNumColumns = min(DIMENSION_MIN_SIZE * width / height, DIMENSION_MAX_SIZE)
+        }
+        val tileLength = min(height / mNumRows, width / mNumColumns)
+        val xStartLocation = (width - tileLength * mNumColumns) / 2
+        val yStartLocation = (height - tileLength * mNumRows) / 2
+
+        mTiles = ArrayList<Rect>()
+        for (i in 0 until mNumRows) {
+            for (j in 0 until mNumColumns) {
+                val rectangle = Rect(
+                    xStartLocation + j * tileLength,
+                    yStartLocation + i * tileLength,
+                    xStartLocation + j * tileLength + tileLength,
+                    yStartLocation + i * tileLength + tileLength
+                )
+                mTiles.add(rectangle)
+            }
+        }
+
+        mBorders = ArrayList<Rect>()
+        // Top border
+        mBorders.add(Rect(0, 0, width, yStartLocation))
+        // Bottom border
+        mBorders.add(Rect(0, yStartLocation + tileLength * mNumRows, width, height))
+        // Left border
+        mBorders.add(Rect(0, 0, xStartLocation, height))
+        // Right border
+        mBorders.add(Rect(xStartLocation + tileLength * mNumColumns, 0, width, height))
+    }
+
+    private fun createMusicTiles(context: Context) {
+        setContentView(MusicTileView(this, mTiles, mBorders, NoteListener(mEngineHandle),
+                ScreenChangeListener { setup() }))
+    }
+
+    class ScreenChangeListener(private var mFunc: () -> Unit) : MusicTileView.ConfigChangeListener {
+        override fun onConfigurationChanged() {
+            mFunc()
+        }
+    }
+
+}

externals/oboe/samples/SoundBoard/src/main/kotlin/com/google/oboe/samples/soundboard/MusicTileView.kt

@@ -0,0 +1,171 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.oboe.samples.soundboard
+
+import android.content.Context
+import android.content.res.Configuration
+import android.graphics.*
+import android.util.SparseArray
+import android.view.MotionEvent
+import android.view.View
+import androidx.core.content.ContextCompat
+
+class MusicTileView(
+    context: Context?,
+    private val mTiles: ArrayList<Rect>,
+    private val mBorders: ArrayList<Rect>,
+    tileListener: TileListener,
+    configChangeListener: ConfigChangeListener
+) : View(context) {
+    private val mIsPressedPerRectangle: BooleanArray = BooleanArray(mTiles.size)
+    private val mPaint: Paint = Paint()
+    private val mLocationsOfFingers: SparseArray<PointF> = SparseArray()
+    private val mTileListener: TileListener
+    private val mConfigChangeListener : ConfigChangeListener
+
+    interface ConfigChangeListener {
+        fun onConfigurationChanged()
+    }
+
+    interface TileListener {
+        fun onTileOn(index: Int)
+        fun onTileOff(index: Int)
+    }
+
+    private fun getIndexFromLocation(pointF: PointF): Int {
+        for (i in mTiles.indices) {
+            if (pointF.x > mTiles[i].left && pointF.x < mTiles[i].right && pointF.y > mTiles[i].top && pointF.y < mTiles[i].bottom) {
+                return i
+            }
+        }
+        return -1
+    }
+
+    override fun onDraw(canvas: Canvas) {
+        for (i in mTiles.indices) {
+            mPaint.style = Paint.Style.FILL
+            if (mIsPressedPerRectangle[i]) {
+                mPaint.color = ContextCompat.getColor(context, R.color.colorPrimary)
+            } else {
+                mPaint.color = Color.BLACK
+            }
+            canvas.drawRect(mTiles[i], mPaint)
+
+            // white border
+            mPaint.style = Paint.Style.STROKE
+            mPaint.strokeWidth = 10f
+            mPaint.color = Color.WHITE
+            canvas.drawRect(mTiles[i], mPaint)
+        }
+        for (i in mBorders.indices) {
+            mPaint.style = Paint.Style.FILL
+            mPaint.color = ContextCompat.getColor(context, R.color.colorPrimaryDark)
+            canvas.drawRect(mBorders[i], mPaint)
+        }
+    }
+
+    override fun onTouchEvent(event: MotionEvent): Boolean {
+        val pointerIndex = event.actionIndex
+        val pointerId = event.getPointerId(pointerIndex)
+        val maskedAction = event.actionMasked
+        var didImageChange = false
+        when (maskedAction) {
+            MotionEvent.ACTION_MOVE -> {
+
+                // Create an array to check for finger changes as multiple fingers may be on the
+                // same tile. This two-pass algorithm records the overall difference before changing
+                // the actual tiles.
+                val notesChangedBy = IntArray(mTiles.size)
+                run {
+                    val size = event.pointerCount
+                    var i = 0
+                    while (i < size) {
+                        val point = mLocationsOfFingers[event.getPointerId(i)]
+                        if (point != null) {
+                            val prevIndex = getIndexFromLocation(point)
+                            point.x = event.getX(i)
+                            point.y = event.getY(i)
+                            val newIndex = getIndexFromLocation(point)
+                            if (newIndex != prevIndex) {
+                                if (prevIndex != -1) {
+                                    notesChangedBy[prevIndex]--
+                                }
+                                if (newIndex != -1) {
+                                    notesChangedBy[newIndex]++
+                                }
+                            }
+                        }
+                        i++
+                    }
+                }
+
+                // Now go through the rectangles to see if they have changed
+                var i = 0
+                while (i < mTiles.size) {
+                    if (notesChangedBy[i] > 0) {
+                        mIsPressedPerRectangle[i] = true
+                        mTileListener.onTileOn(i)
+                        didImageChange = true
+                    } else if (notesChangedBy[i] < 0) {
+                        mIsPressedPerRectangle[i] = false
+                        mTileListener.onTileOff(i)
+                        didImageChange = true
+                    }
+                    i++
+                }
+            }
+            MotionEvent.ACTION_DOWN, MotionEvent.ACTION_POINTER_DOWN -> {
+                val f = PointF()
+                f.x = event.getX(pointerIndex)
+                f.y = event.getY(pointerIndex)
+                mLocationsOfFingers.put(pointerId, f)
+                val curIndex = getIndexFromLocation(f)
+                if (curIndex != -1) {
+                    mIsPressedPerRectangle[curIndex] = true
+                    mTileListener.onTileOn(curIndex)
+                    didImageChange = true
+                }
+            }
+            MotionEvent.ACTION_UP, MotionEvent.ACTION_POINTER_UP, MotionEvent.ACTION_CANCEL -> {
+                val curIndex =
+                    getIndexFromLocation(mLocationsOfFingers[event.getPointerId(pointerIndex)])
+                if (curIndex != -1) {
+                    mIsPressedPerRectangle[curIndex] = false
+                    mTileListener.onTileOff(curIndex)
+                    didImageChange = true
+                }
+                mLocationsOfFingers.remove(pointerId)
+            }
+        }
+
+        // Calling invalidate() will force onDraw() to be called
+        if (didImageChange) {
+            invalidate()
+        }
+        return true
+    }
+
+    override fun onConfigurationChanged(newConfig: Configuration) {
+        super.onConfigurationChanged(newConfig)
+        mConfigChangeListener.onConfigurationChanged()
+    }
+
+    init {
+        mTileListener = tileListener
+        mConfigChangeListener = configChangeListener
+    }
+}

externals/oboe/samples/SoundBoard/src/main/kotlin/com/google/oboe/samples/soundboard/NoteListener.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.oboe.samples.soundboard
+
+import com.google.oboe.samples.soundboard.MusicTileView.TileListener
+
+class NoteListener(private var mEngineHandle: Long) : TileListener {
+    private external fun noteOn(engineHandle: Long, noteIndex: Int)
+    private external fun noteOff(engineHandle: Long, noteIndex: Int)
+    override fun onTileOn(index: Int) {
+        noteOn(mEngineHandle, index)
+    }
+
+    override fun onTileOff(index: Int) {
+        noteOff(mEngineHandle, index)
+    }
+}

externals/oboe/samples/SoundBoard/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,34 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillType="evenOdd"
+        android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="78.5885"
+                android:endY="90.9159"
+                android:startX="48.7653"
+                android:startY="61.0927"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>

externals/oboe/samples/SoundBoard/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector
+    android:height="108dp"
+    android:width="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108"
+    xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#3DDC84"
+          android:pathData="M0,0h108v108h-108z"/>
+    <path android:fillColor="#00000000" android:pathData="M9,0L9,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,0L19,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M29,0L29,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M39,0L39,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M49,0L49,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M59,0L59,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M69,0L69,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M79,0L79,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M89,0L89,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M99,0L99,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,9L108,9"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,19L108,19"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,29L108,29"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,39L108,39"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,49L108,49"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,59L108,59"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,69L108,69"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,79L108,79"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,89L108,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,99L108,99"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,29L89,29"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,39L89,39"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,49L89,49"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,59L89,59"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,69L89,69"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,79L89,79"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M29,19L29,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M39,19L39,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M49,19L49,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M59,19L59,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M69,19L69,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M79,19L79,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+</vector>

externals/oboe/samples/SoundBoard/src/main/res/layout/activity_main.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".MainActivity">
+
+</androidx.constraintlayout.widget.ConstraintLayout>

externals/oboe/samples/SoundBoard/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background"/>
+    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+</adaptive-icon>

externals/oboe/samples/SoundBoard/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background"/>
+    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+</adaptive-icon>

externals/oboe/samples/SoundBoard/src/main/res/values/colors.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="colorPrimary">#700000</color>
+    <color name="colorPrimaryDark">#280000</color>
+    <color name="colorAccent">#D81B60</color>
+</resources>

externals/oboe/samples/SoundBoard/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">soundboard</string>
+</resources>

externals/oboe/samples/SoundBoard/src/main/res/values/styles.xml

@@ -0,0 +1,11 @@
+<resources>
+
+    <!-- Base application theme. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
+        <!-- Customize your theme here. -->
+        <item name="colorPrimary">@color/colorPrimary</item>
+        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
+        <item name="colorAccent">@color/colorAccent</item>
+    </style>
+
+</resources>