Add Android Studio project for OpenGL renderer integration

.github/workflows/android.yml

@@ -0,0 +1,63 @@
+name: Android
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'android/**'
+      - '.github/workflows/android.yml'
+  pull_request:
+    branches: [main]
+    paths:
+      - 'android/**'
+      - '.github/workflows/android.yml'
+  workflow_dispatch:
+
+jobs:
+  build:
+    name: Debug build
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          lfs: true
+
+      - name: Set up Java 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      - name: Install NDK and CMake
+        run: |
+          yes | $ANDROID_SDK_ROOT/cmdline-tools/latest/bin/sdkmanager \
+            "ndk;30.0.14904198" \
+            "cmake;3.22.1"
+
+      - name: Cache Gradle
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: gradle-${{ hashFiles('android/**/*.gradle*', 'android/**/gradle-wrapper.properties') }}
+          restore-keys: gradle-
+
+      - name: Cache NDK build artifacts
+        uses: actions/cache@v4
+        with:
+          path: android/app/.cxx
+          key: ndk-${{ runner.os }}-${{ hashFiles('android/app/src/main/cpp/CMakeLists.txt') }}
+          restore-keys: ndk-${{ runner.os }}-
+
+      - name: Build
+        working-directory: android
+        run: ./gradlew assembleDebug
+
+      - name: Upload APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: hawkeye-android-debug
+          path: android/app/build/outputs/apk/debug/app-debug.apk
+          retention-days: 7

.gitignore

@@ -4,3 +4,13 @@ build-debug/
 build-release/
 .dmux/
 .dmux-hooks/
+
+# Android
+android/local.properties
+android/.gradle/
+android/app/build/
+android/app/.cxx/
+android/build/
+android/.idea/workspace.xml
+android/.claude/
+android/.idea/*

android/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

android/README.md

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+# Hawkeye Android
+
+Android port of the Hawkeye 3D renderer, running the desktop C/Raylib scene natively on Android via NativeActivity and OpenGL ES 3.0.
+
+## Architecture
+
+The app has no Java/Kotlin logic beyond the manifest declaration. `NativeActivity` loads `libhawkeye.so`, which runs a standard C `main()` entry point via Raylib's Android platform backend.
+
+```
+android/
+├── app/src/main/
+│   ├── AndroidManifest.xml       — declares NativeActivity, requires OpenGL ES 3.0
+│   ├── assets/                   — all symlinks into the parent Hawkeye project
+│   │   ├── fonts  -> ../../../../fonts
+│   │   ├── models -> ../../../../models
+│   │   ├── shaders -> ../../../../shaders
+│   │   └── themes -> ../../../../themes
+│   └── cpp/
+│       ├── CMakeLists.txt        — fetches Raylib 5.5, compiles rendering subset
+│       └── android_main.c        — entry point: scene_init + vehicle_init + render loop
+```
+
+The Hawkeye source files compiled in are: `scene.c`, `vehicle.c`, `asset_path.c`, `theme.c`, `ortho_panel.c`. MAVLink, ULog, HUD, and replay code are excluded.
+
+## Shader Compatibility
+
+The original shaders use `#version 330` (desktop OpenGL). On Android they are patched at load time via Raylib's `SetLoadFileTextCallback`:
+
+- `#version 330` → `#version 300 es`
+- `precision mediump float;` is injected into fragment shaders
+
+No shader copies are kept in the Android project — the `shaders/` asset dir is a symlink to the originals.
+
+## Environment Setup
+
+If you haven't done Android development before, here's what you need:
+
+### 1. Install Android Studio
+
+Download and install [Android Studio](https://developer.android.com/studio) for your platform (macOS, Linux, or Windows). The installer includes the Android SDK and the SDK Manager.
+
+### 2. Install the NDK and CMake
+
+Open Android Studio, go to **Settings → Languages & Frameworks → Android SDK → SDK Tools**, check:
+
+- **NDK (Side by side)** — install version `30.0.14904198`
+- **CMake** — install version `3.22.1`
+
+Click **Apply**.
+
+Alternatively, from the command line (replace `$ANDROID_SDK_ROOT` with your SDK path — typically `~/Library/Android/sdk` on macOS or `~/Android/Sdk` on Linux):
+
+```bash
+$ANDROID_SDK_ROOT/cmdline-tools/latest/bin/sdkmanager "ndk;30.0.14904198" "cmake;3.22.1"
+```
+
+### 3. Open the project
+
+Open the `android/` directory in Android Studio. Gradle will sync automatically and download any remaining dependencies.
+
+### Note on symlinks
+
+The `assets/` directory uses symlinks into the parent repo (fonts, models, shaders, themes). These work on macOS and Linux out of the box. On Windows, either enable [Developer Mode](https://learn.microsoft.com/en-us/windows/apps/get-started/enable-your-device-for-development) before cloning or use WSL.
+
+## Requirements
+
+- Android SDK (API 29+)
+- NDK 30.0.14904198
+- CMake 3.22+
+- A device or emulator with OpenGL ES 3.0 support
+
+## Building
+
+```bash
+./gradlew assembleDebug
+```
+
+Raylib 5.5 is fetched automatically by CMake on the first build. Built ABIs: `arm64-v8a`, `x86_64`.
+
+## Deploying
+
+```bash
+adb install -r app/build/outputs/apk/debug/app-debug.apk
+adb shell am start -n com.px4.hawkeye.android/android.app.NativeActivity
+```
+

android/app/.gitignore

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+/build

android/app/build.gradle.kts

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+plugins {
+    alias(libs.plugins.android.application)
+}
+
+android {
+    namespace = "com.px4.hawkeye.android"
+    compileSdk {
+        version = release(36) {
+            minorApiLevel = 1
+        }
+    }
+
+    ndkVersion = "30.0.14904198"
+
+    externalNativeBuild {
+        cmake {
+            path = file("src/main/cpp/CMakeLists.txt")
+            version = "3.22.1"
+        }
+    }
+
+    defaultConfig {
+        applicationId = "com.px4.hawkeye.android"
+        minSdk = 29
+        targetSdk = 36
+        versionCode = 1
+        versionName = "1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+
+        externalNativeBuild {
+            cmake {
+                abiFilters += listOf("arm64-v8a", "x86_64")
+            }
+        }
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+}
+
+dependencies {
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.appcompat)
+    implementation(libs.material)
+    testImplementation(libs.junit)
+    androidTestImplementation(libs.androidx.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+}

android/app/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

android/app/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"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <uses-feature android:glEsVersion="0x00030000" android:required="true" />
+
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.HawkeyeAndroid">
+
+        <activity
+            android:name="android.app.NativeActivity"
+            android:exported="true"
+            android:screenOrientation="landscape"
+            android:configChanges="orientation|screenSize|keyboardHidden">
+
+            <meta-data
+                android:name="android.app.lib_name"
+                android:value="hawkeye" />
+
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+    </application>
+
+</manifest>

android/app/src/main/assets/fonts

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+../../../../../fonts

android/app/src/main/assets/models

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+../../../../../models

android/app/src/main/assets/shaders

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+../../../../../shaders

android/app/src/main/assets/themes

@@ -0,0 +1 @@
+../../../../../themes

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

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+cmake_minimum_required(VERSION 3.22)
+project(hawkeye C)
+
+# Tell Raylib to target Android with OpenGL ES 3.0
+set(PLATFORM "Android" CACHE STRING "" FORCE)
+set(GRAPHICS "GRAPHICS_API_OPENGL_ES3" CACHE STRING "" FORCE)
+
+# Fetch Raylib 5.5 — same version as the desktop project
+include(FetchContent)
+FetchContent_Declare(
+    raylib
+    GIT_REPOSITORY https://github.com/raysan5/raylib.git
+    GIT_TAG        5.5
+    GIT_SHALLOW    TRUE
+)
+FetchContent_MakeAvailable(raylib)
+
+# Hawkeye rendering source subset — no MAVLink/ULog/HUD
+# CMakeLists.txt lives at android/app/src/main/cpp/ — five levels up is the repo root
+set(HAWKEYE_SRC "${CMAKE_CURRENT_SOURCE_DIR}/../../../../../src")
+
+add_library(hawkeye SHARED
+    android_main.c
+    ${HAWKEYE_SRC}/scene.c
+    ${HAWKEYE_SRC}/vehicle.c
+    ${HAWKEYE_SRC}/asset_path.c
+    ${HAWKEYE_SRC}/theme.c
+    ${HAWKEYE_SRC}/ortho_panel.c
+)
+
+target_include_directories(hawkeye PRIVATE
+    ${HAWKEYE_SRC}
+    ${ANDROID_NDK}/sources/android/native_app_glue
+)
+
+target_link_libraries(hawkeye
+    raylib
+    android
+    log
+    EGL
+    GLESv3
+)
+
+# ANativeActivity_onCreate is called by the Android Java runtime via JNI, not by any
+# C code — so the linker would silently strip it from the shared library without this.
+target_link_options(hawkeye PRIVATE "-Wl,-u,ANativeActivity_onCreate")