Update and improve android_gradle (#965)

* Update CMakeLists.txt files so we can build libamber_ndk.so for
Android via CMake.

* `android_gradle/`:

  * Update Gradle version, settings, and build files to match the latest
  Android sample. Importantly, this removes the use of jcenter and
  bintray repositories, which were shut down.

  * Specify NDK version so that Gradle can install required native build
  tools automatically.

  * Define externalNativeBuild so Gradle can perform the Android CMake
  build automatically.

* Replace `main` with `android_main` when building the Amber tool as a
library for Android to avoid compiler warnings, and rename other
Android-related symbols to avoid confusion.

Fixes #964

16 files changed, 101 insertions, 60 deletions

diff --git a/.gitignore b/.gitignore
index 8c314d9..e847034 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,5 +26,5 @@ third_party/robin-hood-hashing
 [._]*.s[a-w][a-z]
 
 # C-Lion
-.idea
-cmake-build-debug
+.idea/
+cmake-build-*/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9f65d5f..c064649 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -202,7 +202,6 @@ endif()
 function(amber_default_compile_options TARGET)
   if (${COMPILER_IS_LIKE_GNU})
     target_compile_options(${TARGET} PRIVATE
-      -std=c++11
       -fno-exceptions
       -fvisibility=hidden
       -Wall
@@ -230,7 +229,6 @@ function(amber_default_compile_options TARGET)
   endif()
 
   if (MSVC)
-    # Specify /EHs for exception handling.
     target_compile_options(${TARGET} PRIVATE
       /bigobj
       /EHsc
@@ -266,6 +264,6 @@ endfunction()
 add_subdirectory(third_party)
 add_subdirectory(src)
 
-if (${AMBER_ENABLE_SAMPLES} AND NOT ANDROID)
+if (${AMBER_ENABLE_SAMPLES})
   add_subdirectory(samples)
 endif()
diff --git a/android_gradle/app/build.gradle b/android_gradle/app/build.gradle
index 40c4c54..b756f6b 100644
--- a/android_gradle/app/build.gradle
+++ b/android_gradle/app/build.gradle
@@ -1,26 +1,37 @@
-apply plugin: 'com.android.application'
+plugins {
+    id 'com.android.application'
+}
 
 android {
-    compileSdkVersion 29
-    buildToolsVersion "29.0.2"
+    compileSdk 30
+    buildToolsVersion "30.0.2"
+    ndkVersion "21.4.7075529"
 
     defaultConfig {
         applicationId "com.google.amber"
         minSdkVersion 24
-        targetSdkVersion 29
+        targetSdkVersion 30
         versionCode 1
         versionName "1.0"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+
+        externalNativeBuild {
+            cmake {
+                arguments "-DAMBER_USE_LOCAL_VULKAN=1"
+                targets "amber_ndk"
+            }
+        }
     }
 
-    sourceSets {
-        androidTest.manifest.srcFile "src/androidTest/AndroidManifest.xml"
+    externalNativeBuild {
+        cmake {
+            path "../../CMakeLists.txt"
+        }
     }
 
-    dependencies {
-        androidTestImplementation 'androidx.test:runner:1.1.0'
-        androidTestImplementation 'androidx.test:rules:1.1.0'
+    sourceSets {
+        androidTest.manifest.srcFile "src/androidTest/AndroidManifest.xml"
     }
 
     buildTypes {
@@ -29,6 +40,10 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt')
         }
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
 
     sourceSets {
         main {
@@ -41,9 +56,10 @@ android {
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
 
-    implementation 'androidx.appcompat:appcompat:1.1.0'
-    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    implementation 'androidx.appcompat:appcompat:1.3.1'
+    implementation 'com.google.android.material:material:1.4.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.1.1'
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
 }
diff --git a/android_gradle/app/src/androidTest/java/com/google/amber/AmberLauncher.java b/android_gradle/app/src/androidTest/java/com/google/amber/AmberLauncher.java
index 4864843..ad92154 100644
--- a/android_gradle/app/src/androidTest/java/com/google/amber/AmberLauncher.java
+++ b/android_gradle/app/src/androidTest/java/com/google/amber/AmberLauncher.java
@@ -54,7 +54,7 @@ public class AmberLauncher {
     String stdout_file = args.getString("stdout", new File(outputDir, "amber_stdout.txt").toString());
     String stderr_file = args.getString("stderr", new File(outputDir, "amber_stderr.txt").toString());
 
-    int res = Amber.androidMain(args_list.toArray(new String[0]), stdout_file, stderr_file);
+    int res = Amber.androidHelper(args_list.toArray(new String[0]), stdout_file, stderr_file);
 
     // If the process crashes during the above call or we call System.exit below, the output
     // from `adb shell am instrument ...` will be:
diff --git a/android_gradle/app/src/main/AndroidManifest.xml b/android_gradle/app/src/main/AndroidManifest.xml
index 0ab9856..c74c390 100644
--- a/android_gradle/app/src/main/AndroidManifest.xml
+++ b/android_gradle/app/src/main/AndroidManifest.xml
@@ -4,6 +4,7 @@
 
     <application
         android:allowBackup="true"
+        android:fullBackupOnly="true"
         android:label="Amber"
         android:supportsRtl="true">
         <meta-data
diff --git a/android_gradle/app/src/main/java/com/google/amber/Amber.java b/android_gradle/app/src/main/java/com/google/amber/Amber.java
index 8319ccf..008c528 100644
--- a/android_gradle/app/src/main/java/com/google/amber/Amber.java
+++ b/android_gradle/app/src/main/java/com/google/amber/Amber.java
@@ -19,5 +19,5 @@ public class Amber {
     System.loadLibrary("amber_ndk");
   }
 
-  public static native int androidMain(String[] args, String stdout_file, String stderr_file);
+  public static native int androidHelper(String[] args, String stdout_file, String stderr_file);
 }
diff --git a/android_gradle/build.gradle b/android_gradle/build.gradle
index 82c93bf..d340082 100644
--- a/android_gradle/build.gradle
+++ b/android_gradle/build.gradle
@@ -4,25 +4,16 @@ buildscript {
 
     repositories {
         google()
-        jcenter()
-        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }
+        mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.0.0-alpha04'
+        classpath 'com.android.tools.build:gradle:7.0.2'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }
 }
 
-allprojects {
-    repositories {
-        google()
-        jcenter()
-        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }
-    }
-}
-
 task clean(type: Delete) {
     delete rootProject.buildDir
 }
diff --git a/android_gradle/gradle.properties b/android_gradle/gradle.properties
index 199d16e..4941ecd 100644
--- a/android_gradle/gradle.properties
+++ b/android_gradle/gradle.properties
@@ -6,7 +6,7 @@
 # http://www.gradle.org/docs/current/userguide/build_environment.html
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
-org.gradle.jvmargs=-Xmx1536m
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
 # When configured, Gradle will run in incubating parallel mode.
 # This option should only be used with decoupled projects. More details, visit
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
diff --git a/android_gradle/gradle/wrapper/gradle-wrapper.jar b/android_gradle/gradle/wrapper/gradle-wrapper.jar
index f6b961f..e708b1c 100644
--- a/android_gradle/gradle/wrapper/gradle-wrapper.jar
+++ b/android_gradle/gradle/wrapper/gradle-wrapper.jar
diff --git a/android_gradle/gradle/wrapper/gradle-wrapper.properties b/android_gradle/gradle/wrapper/gradle-wrapper.properties
index 421d5b6..e81b594 100644
--- a/android_gradle/gradle/wrapper/gradle-wrapper.properties
+++ b/android_gradle/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
-#Mon Dec 09 14:37:37 GMT 2019
+#Sat Sep 25 16:43:12 BST 2021
 distributionBase=GRADLE_USER_HOME
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip
 distributionPath=wrapper/dists
-zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.0-rc-1-all.zip
+zipStoreBase=GRADLE_USER_HOME
diff --git a/android_gradle/settings.gradle b/android_gradle/settings.gradle
index 9a979bb..2c4357f 100644
--- a/android_gradle/settings.gradle
+++ b/android_gradle/settings.gradle
@@ -1,2 +1,9 @@
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
 rootProject.name='Amber'
 include ':app'
diff --git a/samples/Android.mk b/samples/Android.mk
index 6ebdbc8..1428ead 100644
--- a/samples/Android.mk
+++ b/samples/Android.mk
@@ -19,7 +19,6 @@ LOCAL_MODULE:=amber_ndk
 LOCAL_CPP_EXTENSION := .cc .cpp .cxx
 LOCAL_SRC_FILES:= \
     amber.cc \
-    android_main.cc \
     config_helper.cc \
     config_helper_vulkan.cc \
     log.cc \
@@ -31,8 +30,11 @@ LOCAL_LDLIBS:=-landroid -lvulkan -llog
 LOCAL_CXXFLAGS:=-std=c++11 -fno-exceptions -fno-rtti -Werror -Wno-unknown-pragmas -DAMBER_ENGINE_VULKAN=1 -DAMBER_ENABLE_LODEPNG=1
 LOCAL_STATIC_LIBRARIES:=amber lodepng
 include $(BUILD_EXECUTABLE)
+
 LOCAL_MODULE:=amber_ndk_sharedlib
 LOCAL_MODULE_FILENAME:=libamber_ndk
+LOCAL_SRC_FILES+=android_helper.cc
+LOCAL_CXXFLAGS+=-DAMBER_ANDROID_MAIN=1
 include $(BUILD_SHARED_LIBRARY)
 
 include $(LOCAL_PATH)/../Android.mk
diff --git a/samples/CMakeLists.txt b/samples/CMakeLists.txt
index 3fa1882..1e91c4d 100644
--- a/samples/CMakeLists.txt
+++ b/samples/CMakeLists.txt
@@ -74,3 +74,11 @@ target_include_directories(image_diff PRIVATE "${CMAKE_BINARY_DIR}")
 target_link_libraries(image_diff libamber "lodepng")
 amber_default_compile_options(image_diff)
 set_target_properties(image_diff PROPERTIES OUTPUT_NAME "image_diff")
+
+if (ANDROID)
+  add_library(amber_ndk SHARED android_helper.cc ${AMBER_SOURCES})
+  target_include_directories(amber_ndk PRIVATE "${CMAKE_BINARY_DIR}")
+  target_link_libraries(amber_ndk libamber ${AMBER_EXTRA_LIBS})
+  amber_default_compile_options(amber_ndk)
+  target_compile_definitions(amber_ndk PRIVATE AMBER_ANDROID_MAIN=1)
+endif()
diff --git a/samples/amber.cc b/samples/amber.cc
index d037ba4..5973dba 100644
--- a/samples/amber.cc
+++ b/samples/amber.cc
@@ -447,7 +447,15 @@ std::string disassemble(const std::string& env,
 
 }  // namespace
 
+#ifdef AMBER_ANDROID_MAIN
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wmissing-prototypes"
+#pragma ide diagnostic ignored "OCUnusedGlobalDeclarationInspection"
+int android_main(int argc, const char** argv) {
+#pragma clang diagnostic pop
+#else
 int main(int argc, const char** argv) {
+#endif
   std::vector<std::string> args(argv, argv + argc);
   Options options;
   SampleDelegate delegate;
diff --git a/samples/android_main.cc b/samples/android_helper.cc
index b24a9bb..7da69ad 100644
--- a/samples/android_main.cc
+++ b/samples/android_helper.cc
@@ -18,16 +18,20 @@
 #include <string>
 #include <vector>
 
-extern int main(int argc, const char** argv);
+extern int android_main(int argc, const char** argv);
 
-extern "C" JNIEXPORT JNICALL int Java_com_google_amber_Amber_androidMain(
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wmissing-prototypes"
+#pragma ide diagnostic ignored "OCUnusedGlobalDeclarationInspection"
+
+extern "C" JNIEXPORT JNICALL int Java_com_google_amber_Amber_androidHelper(
     JNIEnv* env,
     jobject,
     jobjectArray args,
     jstring stdoutFile,
     jstring stderrFile) {
-  const char* stdout_file_cstr = env->GetStringUTFChars(stdoutFile, NULL);
-  const char* stderr_file_cstr = env->GetStringUTFChars(stderrFile, NULL);
+  const char* stdout_file_cstr = env->GetStringUTFChars(stdoutFile, nullptr);
+  const char* stderr_file_cstr = env->GetStringUTFChars(stderrFile, nullptr);
 
   // Redirect std output to a file
   freopen(stdout_file_cstr, "w", stdout);
@@ -43,7 +47,7 @@ extern "C" JNIEXPORT JNICALL int Java_com_google_amber_Amber_androidMain(
 
   for (jsize i = 0; i < arg_count; i++) {
     jstring js = static_cast<jstring>(env->GetObjectArrayElement(args, i));
-    const char* arg_cstr = env->GetStringUTFChars(js, NULL);
+    const char* arg_cstr = env->GetStringUTFChars(js, nullptr);
     argv_string.push_back(arg_cstr);
     env->ReleaseStringUTFChars(js, arg_cstr);
   }
@@ -53,5 +57,7 @@ extern "C" JNIEXPORT JNICALL int Java_com_google_amber_Amber_androidMain(
   for (const std::string& arg : argv_string)
     argv.push_back(arg.c_str());
 
-  return main(argv.size(), argv.data());
+  return android_main(static_cast<int>(argv.size()), argv.data());
 }
+
+#pragma clang diagnostic pop
diff --git a/third_party/CMakeLists.txt b/third_party/CMakeLists.txt
index 897c666..410dc02 100644
--- a/third_party/CMakeLists.txt
+++ b/third_party/CMakeLists.txt
@@ -52,24 +52,28 @@ endif()
 if (${AMBER_USE_LOCAL_VULKAN})
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/vulkan-headers)
 
-  set(BUILD_TESTS FALSE)
-
-  # The vulkan-loader CMake file assumes that directory exists if
-  # Wayland support is to be built.
-  if(NOT EXISTS ${WAYLAND_CLIENT_INCLUDE_DIR})
-    message(STATUS "Amber: Disabling Wayland support in Vulkan-Loader")
-    set(BUILD_WSI_WAYLAND_SUPPORT OFF CACHE BOOL "" FORCE)
-  endif()
-  message(STATUS "Amber: Disabling X11 support in Vulkan-Loader")
-  set(BUILD_WSI_XLIB_SUPPORT OFF CACHE BOOL "" FORCE)
-
-  set(ROBIN_HOOD_HASHING_INSTALL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/robin-hood-hashing" CACHE STRING "" FORCE)
-
-  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/vulkan-loader)
-  if (MSVC)
-    option(BUILD_WERROR "Treat compiler warnings as errors" OFF)
+  # Skip adding the validation layers and the Vulkan loader on Android.
+  if (NOT ANDROID)
+
+    set(BUILD_TESTS FALSE)
+
+    # The vulkan-loader CMake file assumes that directory exists if
+    # Wayland support is to be built.
+    if(NOT EXISTS ${WAYLAND_CLIENT_INCLUDE_DIR})
+      message(STATUS "Amber: Disabling Wayland support in Vulkan-Loader")
+      set(BUILD_WSI_WAYLAND_SUPPORT OFF CACHE BOOL "" FORCE)
+    endif()
+    message(STATUS "Amber: Disabling X11 support in Vulkan-Loader")
+    set(BUILD_WSI_XLIB_SUPPORT OFF CACHE BOOL "" FORCE)
+
+    set(ROBIN_HOOD_HASHING_INSTALL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/robin-hood-hashing" CACHE STRING "" FORCE)
+
+    add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/vulkan-loader)
+    if (MSVC)
+      option(BUILD_WERROR "Treat compiler warnings as errors" OFF)
+    endif()
+    add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/vulkan-validationlayers)
   endif()
-  add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/vulkan-validationlayers)
 endif()
 
 if (${AMBER_ENABLE_VK_DEBUGGING})