Add example variablerateshading for Android (#1084)

[Why]
Example variablerateshading was not compiled for Android.

[How]
Generate Android version example variablerateshading from android/examples/_template.

android/examples/variablerateshading/CMakeLists.txt

@@ -0,0 +1,35 @@
+cmake_minimum_required(VERSION 3.4.1 FATAL_ERROR)
+
+set(NAME variablerateshading)
+
+set(SRC_DIR ../../../examples/${NAME})
+set(BASE_DIR ../../../base)
+set(EXTERNAL_DIR ../../../external)
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14 -DVK_USE_PLATFORM_ANDROID_KHR -DVK_NO_PROTOTYPES")
+
+file(GLOB EXAMPLE_SRC "${SRC_DIR}/*.cpp")
+
+add_library(native-lib SHARED ${EXAMPLE_SRC})
+
+add_library(native-app-glue STATIC ${ANDROID_NDK}/sources/android/native_app_glue/android_native_app_glue.c)
+
+add_subdirectory(../base ${CMAKE_SOURCE_DIR}/../base)
+
+set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -u ANativeActivity_onCreate")
+
+include_directories(${BASE_DIR})
+include_directories(${EXTERNAL_DIR})
+include_directories(${EXTERNAL_DIR}/glm)
+include_directories(${EXTERNAL_DIR}/imgui)
+include_directories(${EXTERNAL_DIR}/tinygltf)
+include_directories(${ANDROID_NDK}/sources/android/native_app_glue)
+
+target_link_libraries(
+    native-lib
+    native-app-glue
+    libbase
+    android
+    log
+    z
+)

android/examples/variablerateshading/build.gradle

@@ -0,0 +1,65 @@
+apply plugin: 'com.android.application'
+apply from: '../gradle/outputfilename.gradle'
+
+android {
+    compileSdkVersion rootProject.ext.compileSdkVersion
+    defaultConfig {
+        applicationId "de.saschawillems.vulkanVariablerateshading"
+        minSdkVersion rootProject.ext.minSdkVersion
+        targetSdkVersion rootProject.ext.targetSdkVersion
+        versionCode 1
+        versionName "1.0"
+        ndk {
+            abiFilters rootProject.ext.abiFilters
+        }
+        externalNativeBuild {
+            cmake {
+                cppFlags "-std=c++14"
+                arguments "-DANDROID_STL=c++_shared", '-DANDROID_TOOLCHAIN=clang'
+            }
+        }
+    }
+    sourceSets {
+        main.assets.srcDirs = ['assets']
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+    externalNativeBuild {
+        cmake {
+            path "CMakeLists.txt"
+        }
+    }
+}
+
+task copyTask {
+    copy {
+        from '../../common/res/drawable'
+        into "src/main/res/drawable"
+        include 'icon.png'
+    }
+
+    copy {
+        from rootProject.ext.shaderPath + 'glsl/base'
+        into 'assets/shaders/glsl/base'
+        include '*.spv'
+    }
+
+    copy {
+       from rootProject.ext.shaderPath + 'glsl/variablerateshading'
+       into 'assets/shaders/glsl/variablerateshading'
+       include '*.*'
+    }
+
+    copy {
+       from rootProject.ext.assetPath + 'models/sponza'
+       into 'assets/models/sponza'
+       include '*.*'
+    }
+
+}
+
+preBuild.dependsOn copyTask

android/examples/variablerateshading/src/main/AndroidManifest.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="de.saschawillems.vulkanVariablerateshading">
+
+    <application
+        android:label="Vulkan variable rate shading"
+        android:icon="@drawable/icon"
+        android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
+        <activity android:name="de.saschawillems.vulkanSample.VulkanActivity"
+            android:screenOrientation="landscape"
+            android:configChanges="orientation|keyboardHidden">
+            <meta-data android:name="android.app.lib_name"
+                android:value="native-lib" />
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+    <uses-feature android:name="android.hardware.touchscreen" android:required="false" />
+    <uses-feature android:name="android.hardware.gamepad" android:required="false" />
+
+</manifest>

android/examples/variablerateshading/src/main/java/de/saschawillems/vulkanSample/VulkanActivity.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2018 by Sascha Willems - www.saschawillems.de
+ *
+ * This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
+ */
+package de.saschawillems.vulkanSample;
+
+import android.app.AlertDialog;
+import android.app.NativeActivity;
+import android.content.DialogInterface;
+import android.content.pm.ApplicationInfo;
+import android.os.Bundle;
+
+import java.util.concurrent.Semaphore;
+
+public class VulkanActivity extends NativeActivity {
+
+    static {
+        // Load native library
+        System.loadLibrary("native-lib");
+    }
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+    }
+
+    // Use a semaphore to create a modal dialog
+
+    private final Semaphore semaphore = new Semaphore(0, true);
+
+    public void showAlert(final String message)
+    {
+        final VulkanActivity activity = this;
+
+        ApplicationInfo applicationInfo = activity.getApplicationInfo();
+        final String applicationName = applicationInfo.nonLocalizedLabel.toString();
+
+        this.runOnUiThread(new Runnable() {
+           public void run() {
+               AlertDialog.Builder builder = new AlertDialog.Builder(activity, android.R.style.Theme_Material_Dialog_Alert);
+               builder.setTitle(applicationName);
+               builder.setMessage(message);
+               builder.setPositiveButton("Close", new DialogInterface.OnClickListener() {
+                   public void onClick(DialogInterface dialog, int id) {
+                       semaphore.release();
+                   }
+               });
+               builder.setCancelable(false);
+               AlertDialog dialog = builder.create();
+               dialog.show();
+           }
+        });
+        try {
+            semaphore.acquire();
+        }
+        catch (InterruptedException e) { }
+    }
+}