Add android support for the game engine.

attachments/simple_engine/CMakeLists.txt

@@ -8,41 +8,21 @@ project(SimpleEngine VERSION 1.0.0 LANGUAGES CXX C)
 # Add CMake module path for custom find modules
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/../CMake")
 
+if(ANDROID)
+    include(FetchContent)
+    FetchContent_Declare(
+      VulkanHeaders
+      GIT_REPOSITORY https://github.com/KhronosGroup/Vulkan-Headers.git
+      GIT_TAG v1.3.275 # Or a specific tag/commit  This needs to correspond to the NDK version of Vulkan.
+    )
+    FetchContent_MakeAvailable(VulkanHeaders)
+endif ()
+
 # Find required packages
-find_package (glfw3 REQUIRED)
 find_package (glm REQUIRED)
 find_package (Vulkan REQUIRED)
 find_package (tinygltf REQUIRED)
 find_package (KTX REQUIRED)
-find_package (OpenAL REQUIRED)
-
-# set up Vulkan C++ module
-add_library(VulkanCppModule)
-add_library(Vulkan::cppm ALIAS VulkanCppModule)
-
-target_compile_definitions(VulkanCppModule
-        PUBLIC VULKAN_HPP_DISPATCH_LOADER_DYNAMIC=1 VULKAN_HPP_NO_STRUCT_CONSTRUCTORS=1
-)
-target_include_directories(VulkanCppModule
-        PRIVATE
-        "${Vulkan_INCLUDE_DIR}"
-)
-target_link_libraries(VulkanCppModule
-        PUBLIC
-        Vulkan::Vulkan
-)
-
-set_target_properties(VulkanCppModule PROPERTIES CXX_STANDARD 20)
-
-target_sources(VulkanCppModule
-        PUBLIC
-        FILE_SET cxx_modules TYPE CXX_MODULES
-        BASE_DIRS
-        "${Vulkan_INCLUDE_DIR}"
-        FILES
-        "${Vulkan_INCLUDE_DIR}/vulkan/vulkan.cppm"
-)
-
 
 
 # Platform-specific settings
@@ -52,6 +32,8 @@ if(ANDROID)
 else()
     # Desktop-specific settings
     add_definitions(-DPLATFORM_DESKTOP)
+    find_package (glfw3 REQUIRED)
+    find_package (OpenAL REQUIRED)
 endif()
 
 # Shader compilation
@@ -117,22 +99,42 @@ set(SOURCES
     mikktspace.c
 )
 
-# Create executable
-add_executable(SimpleEngine ${SOURCES})
+# Create executable or library based on the platform
+if(ANDROID)
+    add_library(SimpleEngine STATIC ${SOURCES})
+else()
+    add_executable(SimpleEngine ${SOURCES})
+endif()
+
 add_dependencies(SimpleEngine shaders)
 set_target_properties (SimpleEngine PROPERTIES CXX_STANDARD 20)
 
 # Link libraries
-target_link_libraries(SimpleEngine PRIVATE
-    Vulkan::cppm
+target_link_libraries(SimpleEngine PUBLIC
+    Vulkan::Vulkan
+    Vulkan::Headers
     glm::glm
     tinygltf::tinygltf
     KTX::ktx
-    OpenAL::OpenAL
 )
 
-if(NOT ANDROID)
-    target_link_libraries(SimpleEngine PRIVATE glfw)
+if(ANDROID)
+    target_link_libraries(SimpleEngine PUBLIC
+        android
+        log
+        EGL
+        GLESv2
+        game-activity::game-activity
+        OpenSLES
+    )
+    target_include_directories(SimpleEngine PUBLIC
+        ${VulkanHeaders_SOURCE_DIR}/include
+        ${ANDROID_NDK}/sources/android/native_app_glue
+    )
+    target_compile_definitions(SimpleEngine PRIVATE VULKAN_HPP_NO_STRUCT_CONSTRUCTORS)
+else()
+    target_link_libraries(SimpleEngine PRIVATE glfw OpenAL::OpenAL)
+    target_compile_definitions(SimpleEngine PRIVATE VULKAN_HPP_NO_STRUCT_CONSTRUCTORS VULKAN_HPP_DISPATCH_LOADER_DYNAMIC)
 endif()
 
 # Copy model and texture files if they exist

attachments/simple_engine/android/README.adoc

@@ -0,0 +1,51 @@
+= Android Project for Vulkan Game Engine Tutorial
+
+This Android project allows you to run the Game Engine's example code in Android.  It demonstrates how to manage a non-trivial project across Desktop and mobile environments from the same code base.
+
+== Project Overview
+
+The Vulkan Game Engine Tutorial is a comprehensive learning project that showcases modern graphics programming using the Vulkan API.
+This Android port enables running the same engine code on mobile devices, demonstrating cross-platform development practices.
+
+== Prerequisites
+
+* Android Studio 4.2 or higher
+* Android NDK r21 or higher
+* CMake 3.10+
+* Vulkan SDK
+* Android device with Vulkan support (Android 7.0+)
+
+== Building and Running
+
+1. Open the project in Android Studio
+2. Sync Gradle files
+3. Build the project
+4. Run on your Android device or emulator
+
+== Project Structure
+
+* `app/` - Android-specific code and resources
+* `src/` - Shared C++ engine code
+* `assets/` - Shared game assets and shaders (automatically copied by Gradle)
+** `models/` - GLTF/GLB model files
+** `shaders/` - Compiled SPIR-V shader files
+** `textures/` - Texture assets
+* `CMake/` - Build configuration files
+
+== Asset Management
+
+The project uses Gradle to automatically handle asset deployment.
+Place your assets in the following source locations:
+
+* Source assets location: `<project_root>/assets/`
+* Gradle will automatically copy assets to: `app/src/main/assets/`
+* Asset changes will be synchronized during build
+
+== Key Components
+
+* GLTF model loading support
+* Cross-platform rendering pipeline
+* JSON configuration using nlohmann_json
+* Unified asset management system with Gradle automation
+
+The project demonstrates professional-grade techniques for maintaining a single codebase that targets both desktop and mobile platforms while leveraging modern C++20 features and Vulkan's cross-platform capabilities.

attachments/simple_engine/android/app/build.gradle

@@ -0,0 +1,64 @@
+plugins {
+    id 'com.android.application'
+}
+
+android {
+    namespace "com.simple_engine"
+    compileSdk 36
+    defaultConfig {
+        applicationId "com.simple_engine"
+        minSdk 24
+        targetSdk 36
+        versionCode 1
+        versionName "1.0"
+
+        externalNativeBuild {
+            cmake {
+                abiFilters 'arm64-v8a', 'x86_64'
+            }
+        }
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_11
+        targetCompatibility JavaVersion.VERSION_11
+    }
+
+    externalNativeBuild {
+        cmake {
+            path "src/main/cpp/CMakeLists.txt"
+            version "4.0.2+"
+        }
+    }
+
+    ndkVersion "28.1.13356709"
+
+    // Use assets from the dedicated assets directory and locally compiled shaders
+    sourceSets {
+        main {
+            assets {
+                srcDirs = [
+                    // Point to the dedicated assets directory
+                    '../../Assets/'
+                ]
+            }
+        }
+    }
+    buildFeatures {
+        prefab true
+        buildConfig true
+    }
+}
+
+dependencies {
+    implementation 'androidx.appcompat:appcompat:1.7.1'
+    implementation 'com.google.android.material:material:1.12.0'
+    implementation 'androidx.games:games-activity:4.0.0'
+}

attachments/simple_engine/android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Declare that this app uses Vulkan -->
+    <uses-feature android:name="android.hardware.vulkan.version" android:version="0x400003" android:required="true" />
+    <uses-feature android:name="android.hardware.vulkan.level" android:version="0" android:required="true" />
+
+    <application
+        android:allowBackup="true"
+        android:fullBackupContent="@xml/backup_rules"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme">
+        <activity
+            android:name=".VulkanActivity"
+            android:configChanges="orientation|keyboardHidden|screenSize"
+            android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+            <meta-data
+                android:name="android.app.lib_name"
+                android:value="simple_engine_android" />
+        </activity>
+    </application>
+
+</manifest>

attachments/simple_engine/android/app/src/main/cpp/CMakeLists.txt

@@ -0,0 +1,29 @@
+cmake_minimum_required(VERSION 3.22.1)
+
+project(simple_engine_android)
+
+# Add the parent project's cmake folder to the module path
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../../../../../../attachments/CMake")
+
+# Include the game-activity library
+find_package(game-activity REQUIRED CONFIG)
+
+# Set C++ standard to match the main project
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# Add the simple_engine project as a subdirectory
+add_subdirectory("${CMAKE_CURRENT_SOURCE_DIR}/../../../../.." simple_engine_build)
+
+# Add the main native library
+add_library(simple_engine_android SHARED
+    game_activity_bridge.cpp
+)
+
+# Link against libraries
+target_link_libraries(simple_engine_android
+    SimpleEngine
+    game-activity::game-activity
+    android
+    log
+)

attachments/simple_engine/android/app/src/main/cpp/game_activity_bridge.cpp

@@ -0,0 +1,13 @@
+// Intentionally empty bridge: rely entirely on GameActivity's native_app_glue
+// provided by the prefab (libgame-activity). That glue will invoke our
+// android_main(android_app*) defined in main.cpp. Defining another
+// GameActivity_onCreate here causes duplicate symbol linker errors.
+// Keeping a translation unit avoids removing the target from CMake.
+
+#include <android/log.h>
+
+#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "SimpleEngine", __VA_ARGS__))
+#define LOGW(...) ((void)__android_log_print(ANDROID_LOG_WARN, "SimpleEngine", __VA_ARGS__))
+#define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, "SimpleEngine", __VA_ARGS__))
+
+// Nothing to do here.

attachments/simple_engine/android/app/src/main/java/com/simple_engine/VulkanActivity.java

@@ -0,0 +1,20 @@
+package com.simple_engine;
+
+import android.os.Bundle;
+import android.view.WindowManager;
+import com.google.androidgamesdk.GameActivity;
+
+public class VulkanActivity extends GameActivity {
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        // Keep the screen on while the app is running
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
+    }
+
+    // Load the native library
+    static {
+        System.loadLibrary("simple_engine_android");
+    }
+}

attachments/simple_engine/android/app/src/main/res/values/strings.xml

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

attachments/simple_engine/android/app/src/main/res/values/styles.xml

@@ -0,0 +1,6 @@
+<resources>
+    <!-- Base application theme -->
+    <style name="AppTheme" parent="android:Theme.Material.Light.NoActionBar">
+        <!-- Customize your theme here -->
+    </style>
+</resources>

attachments/simple_engine/android/app/src/main/res/xml/backup_rules.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<full-backup-content>
+    <!-- Backup everything by default -->
+    <include domain="root" path="."/>
+    <include domain="file" path="."/>
+    <include domain="database" path="."/>
+    <include domain="sharedpref" path="."/>
+    <include domain="external" path="."/>
+</full-backup-content>

attachments/simple_engine/android/app/src/main/res/xml/data_extraction_rules.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<data-extraction-rules>
+    <cloud-backup>
+        <!-- Include all data by default -->
+        <include domain="root" path="."/>
+        <include domain="file" path="."/>
+        <include domain="database" path="."/>
+        <include domain="sharedpref" path="."/>
+        <include domain="external" path="."/>
+    </cloud-backup>
+    <device-transfer>
+        <!-- Include all data by default -->
+        <include domain="root" path="."/>
+        <include domain="file" path="."/>
+        <include domain="database" path="."/>
+        <include domain="sharedpref" path="."/>
+        <include domain="external" path="."/>
+    </device-transfer>
+</data-extraction-rules>

attachments/simple_engine/android/build.gradle

@@ -0,0 +1,18 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:8.13.1'
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+// For Gradle 9.0+, use the Delete interface instead of type
+tasks.register('clean', Delete) {
+    delete rootProject.buildDir
+}

attachments/simple_engine/android/gradle.properties

@@ -0,0 +1,10 @@
+android.useAndroidX=true
+android.enableJetifier=false
+
+# Gradle 9.0+ compatibility settings
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+org.gradle.parallel=true
+org.gradle.caching=true
+android.nonTransitiveRClass=true
+android.nonFinalResIds=true
+org.gradle.configuration-cache=true