Re-architecture of the Godot Android plugin.

10 files changed, 659 insertions, 408 deletions

diff --git a/platform/android/java/lib/build.gradle b/platform/android/java/lib/build.gradle
index 4b5873ce25..ca8aaf8af0 100644
--- a/platform/android/java/lib/build.gradle
+++ b/platform/android/java/lib/build.gradle
@@ -3,6 +3,7 @@ apply plugin: 'com.android.library'
 dependencies {
     implementation libraries.supportCoreUtils
     implementation libraries.kotlinStdLib
+    implementation libraries.v4Support
 }
 
 def pathToRootDir = "../../../../"
diff --git a/platform/android/java/lib/src/org/godotengine/godot/Godot.java b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
index ac1032dab6..7db4aa6597 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/Godot.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/Godot.java
@@ -61,8 +61,11 @@ import android.os.Messenger;
 import android.os.VibrationEffect;
 import android.os.Vibrator;
 import android.provider.Settings.Secure;
+import android.support.annotation.CallSuper;
 import android.support.annotation.Keep;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.v4.app.FragmentActivity;
 import android.view.Display;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
@@ -87,22 +90,20 @@ import com.google.android.vending.expansion.downloader.IStub;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.InputStream;
-import java.lang.reflect.Method;
 import java.security.MessageDigest;
-import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
-import javax.microedition.khronos.opengles.GL10;
 import org.godotengine.godot.input.GodotEditText;
 import org.godotengine.godot.payments.PaymentsManager;
+import org.godotengine.godot.plugin.GodotPlugin;
+import org.godotengine.godot.plugin.GodotPluginRegistry;
 import org.godotengine.godot.utils.GodotNetUtils;
 import org.godotengine.godot.utils.PermissionsUtil;
 import org.godotengine.godot.xr.XRMode;
 
-public abstract class Godot extends Activity implements SensorEventListener, IDownloaderClient {
+public abstract class Godot extends FragmentActivity implements SensorEventListener, IDownloaderClient {
 
-	static final int MAX_SINGLETONS = 64;
 	private IStub mDownloaderClientStub;
 	private TextView mStatusText;
 	private TextView mProgressFraction;
@@ -126,8 +127,7 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 	private boolean activityResumed;
 	private int mState;
 
-	// Used to dispatch events to the main thread.
-	private final Handler mainThreadHandler = new Handler(Looper.getMainLooper());
+	private GodotPluginRegistry pluginRegistry;
 
 	static private Intent mCurrentIntent;
 
@@ -154,83 +154,6 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 		mPauseButton.setText(stringResourceID);
 	}
 
-	static public class SingletonBase {
-
-		protected void registerClass(String p_name, String[] p_methods) {
-
-			GodotLib.singleton(p_name, this);
-
-			Class clazz = getClass();
-			Method[] methods = clazz.getDeclaredMethods();
-			for (Method method : methods) {
-				boolean found = false;
-
-				for (String s : p_methods) {
-					if (s.equals(method.getName())) {
-						found = true;
-						break;
-					}
-				}
-				if (!found)
-					continue;
-
-				List<String> ptr = new ArrayList<String>();
-
-				Class[] paramTypes = method.getParameterTypes();
-				for (Class c : paramTypes) {
-					ptr.add(c.getName());
-				}
-
-				String[] pt = new String[ptr.size()];
-				ptr.toArray(pt);
-
-				GodotLib.method(p_name, method.getName(), method.getReturnType().getName(), pt);
-			}
-
-			Godot.singletons[Godot.singleton_count++] = this;
-		}
-
-		/**
-		 * Invoked once during the Godot Android initialization process after creation of the
-		 * {@link GodotView} view.
-		 * <p>
-		 * This method should be overridden by descendants of this class that would like to add
-		 * their view/layout to the Godot view hierarchy.
-		 *
-		 * @return the view to be included; null if no views should be included.
-		 */
-		@Nullable
-		protected View onMainCreateView(Activity activity) {
-			return null;
-		}
-
-		protected void onMainActivityResult(int requestCode, int resultCode, Intent data) {
-		}
-
-		protected void onMainRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
-		}
-
-		protected void onMainPause() {}
-		protected void onMainResume() {}
-		protected void onMainDestroy() {}
-		protected boolean onMainBackPressed() { return false; }
-
-		protected void onGLDrawFrame(GL10 gl) {}
-		protected void onGLSurfaceChanged(GL10 gl, int width, int height) {} // singletons will always miss first onGLSurfaceChanged call
-		//protected void onGLSurfaceCreated(GL10 gl, EGLConfig config) {} // singletons won't be ready until first GodotLib.step()
-
-		public void registerMethods() {}
-	}
-
-	/*
-	protected List<SingletonBase> singletons = new ArrayList<SingletonBase>();
-	protected void instanceSingleton(SingletonBase s) {
-
-		s.registerMethods();
-		singletons.add(s);
-	}
-	*/
-
 	private String[] command_line;
 	private boolean use_apk_expansion;
 
@@ -246,9 +169,6 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 	public static GodotIO io;
 	public static GodotNetUtils netUtils;
 
-	static SingletonBase[] singletons = new SingletonBase[MAX_SINGLETONS];
-	static int singleton_count = 0;
-
 	public interface ResultCallback {
 		public void callback(int requestCode, int resultCode, Intent data);
 	}
@@ -265,16 +185,15 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 			result_callback = null;
 		};
 
-		for (int i = 0; i < singleton_count; i++) {
-
-			singletons[i].onMainActivityResult(requestCode, resultCode, data);
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onMainActivityResult(requestCode, resultCode, data);
 		}
 	};
 
 	@Override
 	public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
-		for (int i = 0; i < singleton_count; i++) {
-			singletons[i].onMainRequestPermissionsResult(requestCode, permissions, grantResults);
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onMainRequestPermissionsResult(requestCode, permissions, grantResults);
 		}
 
 		for (int i = 0; i < permissions.length; i++) {
@@ -283,6 +202,16 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 	};
 
 	/**
+	 * Invoked on the GL thread when the Godot main loop has started.
+	 */
+	@CallSuper
+	protected void onGLGodotMainLoopStarted() {
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onGLGodotMainLoopStarted();
+		}
+	}
+
+	/**
 	 * Used by the native code (java_godot_lib_jni.cpp) to complete initialization of the GLSurfaceView view and renderer.
 	 */
 	@Keep
@@ -302,14 +231,13 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 		edittext.setView(mView);
 		io.setEdit(edittext);
 
-		final Godot godot = this;
 		mView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
 			@Override
 			public void onGlobalLayout() {
 				Point fullSize = new Point();
-				godot.getWindowManager().getDefaultDisplay().getSize(fullSize);
+				getWindowManager().getDefaultDisplay().getSize(fullSize);
 				Rect gameSize = new Rect();
-				godot.mView.getWindowVisibleDisplayFrame(gameSize);
+				mView.getWindowVisibleDisplayFrame(gameSize);
 
 				final int keyboardHeight = fullSize.y - gameSize.bottom;
 				GodotLib.setVirtualKeyboardHeight(keyboardHeight);
@@ -321,23 +249,23 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 			@Override
 			public void run() {
 				GodotLib.setup(current_command_line);
-				setKeepScreenOn("True".equals(GodotLib.getGlobal("display/window/energy_saving/keep_screen_on")));
 
-				// The Godot Android plugins are setup on completion of GodotLib.setup
-				mainThreadHandler.post(new Runnable() {
-					@Override
-					public void run() {
-						// Include the non-null views returned in the Godot view hierarchy.
-						for (int i = 0; i < singleton_count; i++) {
-							View view = singletons[i].onMainCreateView(Godot.this);
-							if (view != null) {
-								layout.addView(view);
-							}
-						}
-					}
-				});
+				// Must occur after GodotLib.setup has completed.
+				for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+					plugin.onGLRegisterPluginWithGodotNative();
+				}
+
+				setKeepScreenOn("True".equals(GodotLib.getGlobal("display/window/energy_saving/keep_screen_on")));
 			}
 		});
+
+		// Include the returned non-null views in the Godot view hierarchy.
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			View pluginView = plugin.onMainCreateView(this);
+			if (pluginView != null) {
+				layout.addView(pluginView);
+			}
+		}
 	}
 
 	public void setKeepScreenOn(final boolean p_enabled) {
@@ -535,6 +463,7 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 		Window window = getWindow();
 		window.addFlags(WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
 		mClipboard = (ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE);
+		pluginRegistry = GodotPluginRegistry.initializePluginRegistry(this);
 
 		//check for apk expansion API
 		if (true) {
@@ -675,8 +604,8 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 	protected void onDestroy() {
 
 		if (mPaymentsManager != null) mPaymentsManager.destroy();
-		for (int i = 0; i < singleton_count; i++) {
-			singletons[i].onMainDestroy();
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onMainDestroy();
 		}
 
 		GodotLib.ondestroy(this);
@@ -703,8 +632,8 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 
 		mSensorManager.unregisterListener(this);
 
-		for (int i = 0; i < singleton_count; i++) {
-			singletons[i].onMainPause();
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onMainPause();
 		}
 	}
 
@@ -755,9 +684,8 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 					View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
 		}
 
-		for (int i = 0; i < singleton_count; i++) {
-
-			singletons[i].onMainResume();
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onMainResume();
 		}
 	}
 
@@ -850,8 +778,8 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 	public void onBackPressed() {
 		boolean shouldQuit = true;
 
-		for (int i = 0; i < singleton_count; i++) {
-			if (singletons[i].onMainBackPressed()) {
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			if (plugin.onMainBackPressed()) {
 				shouldQuit = false;
 			}
 		}
@@ -866,6 +794,17 @@ public abstract class Godot extends Activity implements SensorEventListener, IDo
 		}
 	}
 
+	/**
+	 * Queue a runnable to be run on the GL thread.
+	 * <p>
+	 * This must be called after the GL thread has started.
+	 */
+	public final void runOnGLThread(@NonNull Runnable action) {
+		if (mView != null) {
+			mView.queueEvent(action);
+		}
+	}
+
 	private void forceQuit() {
 		System.exit(0);
 	}
diff --git a/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java b/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java
index 9ee29d439c..89a65aea24 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java
@@ -176,22 +176,6 @@ public class GodotLib {
 	public static native void audio();
 
 	/**
-	 * Used to setup a {@link org.godotengine.godot.Godot.SingletonBase} instance.
-	 * @param p_name Name of the instance.
-	 * @param p_object Reference to the singleton instance.
-	 */
-	public static native void singleton(String p_name, Object p_object);
-
-	/**
-	 * Used to complete registration of the {@link org.godotengine.godot.Godot.SingletonBase} instance's methods.
-	 * @param p_sname Name of the instance
-	 * @param p_name Name of the method to register
-	 * @param p_ret Return type of the registered method
-	 * @param p_params Method parameters types
-	 */
-	public static native void method(String p_sname, String p_name, String p_ret, String[] p_params);
-
-	/**
 	 * Used to access Godot global properties.
 	 * @param p_key Property key
 	 * @return String value of the property
diff --git a/platform/android/java/lib/src/org/godotengine/godot/GodotPaymentV3.java b/platform/android/java/lib/src/org/godotengine/godot/GodotPaymentV3.java
deleted file mode 100644
index 93265d509f..0000000000
--- a/platform/android/java/lib/src/org/godotengine/godot/GodotPaymentV3.java
+++ /dev/null
@@ -1,230 +0,0 @@
-/*************************************************************************/
-/*  GodotPaymentV3.java                                                  */
-/*************************************************************************/
-/*                       This file is part of:                           */
-/*                           GODOT ENGINE                                */
-/*                      https://godotengine.org                          */
-/*************************************************************************/
-/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
-/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
-/*                                                                       */
-/* Permission is hereby granted, free of charge, to any person obtaining */
-/* a copy of this software and associated documentation files (the       */
-/* "Software"), to deal in the Software without restriction, including   */
-/* without limitation the rights to use, copy, modify, merge, publish,   */
-/* distribute, sublicense, and/or sell copies of the Software, and to    */
-/* permit persons to whom the Software is furnished to do so, subject to */
-/* the following conditions:                                             */
-/*                                                                       */
-/* The above copyright notice and this permission notice shall be        */
-/* included in all copies or substantial portions of the Software.       */
-/*                                                                       */
-/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
-/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
-/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
-/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
-/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
-/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
-/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
-/*************************************************************************/
-
-package org.godotengine.godot;
-
-import android.app.Activity;
-import android.util.Log;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import org.godotengine.godot.payments.PaymentsManager;
-import org.json.JSONException;
-import org.json.JSONObject;
-
-public class GodotPaymentV3 extends Godot.SingletonBase {
-
-	private Godot activity;
-	private Integer purchaseCallbackId = 0;
-	private String accessToken;
-	private String purchaseValidationUrlPrefix;
-	private String transactionId;
-	private PaymentsManager mPaymentManager;
-	private Dictionary mSkuDetails = new Dictionary();
-
-	public void purchase(final String sku, final String transactionId) {
-		activity.runOnUiThread(new Runnable() {
-			@Override
-			public void run() {
-				mPaymentManager.requestPurchase(sku, transactionId);
-			}
-		});
-	}
-
-	static public Godot.SingletonBase initialize(Activity p_activity) {
-
-		return new GodotPaymentV3(p_activity);
-	}
-
-	public GodotPaymentV3(Activity p_activity) {
-
-		registerClass("GodotPayments", new String[] { "purchase", "setPurchaseCallbackId", "setPurchaseValidationUrlPrefix", "setTransactionId", "getSignature", "consumeUnconsumedPurchases", "requestPurchased", "setAutoConsume", "consume", "querySkuDetails", "isConnected" });
-		activity = (Godot)p_activity;
-		mPaymentManager = activity.getPaymentsManager();
-		mPaymentManager.setBaseSingleton(this);
-	}
-
-	public void consumeUnconsumedPurchases() {
-		activity.runOnUiThread(new Runnable() {
-			@Override
-			public void run() {
-				mPaymentManager.consumeUnconsumedPurchases();
-			}
-		});
-	}
-
-	private String signature;
-
-	public String getSignature() {
-		return this.signature;
-	}
-
-	public void callbackSuccess(String ticket, String signature, String sku) {
-		GodotLib.calldeferred(purchaseCallbackId, "purchase_success", new Object[] { ticket, signature, sku });
-	}
-
-	public void callbackSuccessProductMassConsumed(String ticket, String signature, String sku) {
-		Log.d(this.getClass().getName(), "callbackSuccessProductMassConsumed > " + ticket + "," + signature + "," + sku);
-		GodotLib.calldeferred(purchaseCallbackId, "consume_success", new Object[] { ticket, signature, sku });
-	}
-
-	public void callbackSuccessNoUnconsumedPurchases() {
-		GodotLib.calldeferred(purchaseCallbackId, "consume_not_required", new Object[] {});
-	}
-
-	public void callbackFailConsume(String message) {
-		GodotLib.calldeferred(purchaseCallbackId, "consume_fail", new Object[] { message });
-	}
-
-	public void callbackFail(String message) {
-		GodotLib.calldeferred(purchaseCallbackId, "purchase_fail", new Object[] { message });
-	}
-
-	public void callbackCancel() {
-		GodotLib.calldeferred(purchaseCallbackId, "purchase_cancel", new Object[] {});
-	}
-
-	public void callbackAlreadyOwned(String sku) {
-		GodotLib.calldeferred(purchaseCallbackId, "purchase_owned", new Object[] { sku });
-	}
-
-	public int getPurchaseCallbackId() {
-		return purchaseCallbackId;
-	}
-
-	public void setPurchaseCallbackId(int purchaseCallbackId) {
-		this.purchaseCallbackId = purchaseCallbackId;
-	}
-
-	public String getPurchaseValidationUrlPrefix() {
-		return this.purchaseValidationUrlPrefix;
-	}
-
-	public void setPurchaseValidationUrlPrefix(String url) {
-		this.purchaseValidationUrlPrefix = url;
-	}
-
-	public String getAccessToken() {
-		return accessToken;
-	}
-
-	public void setAccessToken(String accessToken) {
-		this.accessToken = accessToken;
-	}
-
-	public void setTransactionId(String transactionId) {
-		this.transactionId = transactionId;
-	}
-
-	public String getTransactionId() {
-		return this.transactionId;
-	}
-
-	// request purchased items are not consumed
-	public void requestPurchased() {
-		activity.runOnUiThread(new Runnable() {
-			@Override
-			public void run() {
-				mPaymentManager.requestPurchased();
-			}
-		});
-	}
-
-	// callback for requestPurchased()
-	public void callbackPurchased(String receipt, String signature, String sku) {
-		GodotLib.calldeferred(purchaseCallbackId, "has_purchased", new Object[] { receipt, signature, sku });
-	}
-
-	public void callbackDisconnected() {
-		GodotLib.calldeferred(purchaseCallbackId, "iap_disconnected", new Object[] {});
-	}
-
-	public void callbackConnected() {
-		GodotLib.calldeferred(purchaseCallbackId, "iap_connected", new Object[] {});
-	}
-
-	// true if connected, false otherwise
-	public boolean isConnected() {
-		return mPaymentManager.isConnected();
-	}
-
-	// consume item automatically after purchase. default is true.
-	public void setAutoConsume(boolean autoConsume) {
-		mPaymentManager.setAutoConsume(autoConsume);
-	}
-
-	// consume a specific item
-	public void consume(String sku) {
-		mPaymentManager.consume(sku);
-	}
-
-	// query in app item detail info
-	public void querySkuDetails(String[] list) {
-		List<String> nKeys = Arrays.asList(list);
-		List<String> cKeys = Arrays.asList(mSkuDetails.get_keys());
-		ArrayList<String> fKeys = new ArrayList<String>();
-		for (String key : nKeys) {
-			if (!cKeys.contains(key)) {
-				fKeys.add(key);
-			}
-		}
-		if (fKeys.size() > 0) {
-			mPaymentManager.querySkuDetails(fKeys.toArray(new String[0]));
-		} else {
-			completeSkuDetail();
-		}
-	}
-
-	public void addSkuDetail(String itemJson) {
-		JSONObject o = null;
-		try {
-			o = new JSONObject(itemJson);
-			Dictionary item = new Dictionary();
-			item.put("type", o.optString("type"));
-			item.put("product_id", o.optString("productId"));
-			item.put("title", o.optString("title"));
-			item.put("description", o.optString("description"));
-			item.put("price", o.optString("price"));
-			item.put("price_currency_code", o.optString("price_currency_code"));
-			item.put("price_amount", 0.000001d * o.optLong("price_amount_micros"));
-			mSkuDetails.put(item.get("product_id").toString(), item);
-		} catch (JSONException e) {
-			e.printStackTrace();
-		}
-	}
-
-	public void completeSkuDetail() {
-		GodotLib.calldeferred(purchaseCallbackId, "sku_details_complete", new Object[] { mSkuDetails });
-	}
-
-	public void errorSkuDetail(String errorMessage) {
-		GodotLib.calldeferred(purchaseCallbackId, "sku_details_error", new Object[] { errorMessage });
-	}
-}
diff --git a/platform/android/java/lib/src/org/godotengine/godot/GodotRenderer.java b/platform/android/java/lib/src/org/godotengine/godot/GodotRenderer.java
index 26fa033f12..ee9a2aee4f 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/GodotRenderer.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/GodotRenderer.java
@@ -30,9 +30,12 @@
 
 package org.godotengine.godot;
 
+import android.content.Context;
 import android.opengl.GLSurfaceView;
 import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.opengles.GL10;
+import org.godotengine.godot.plugin.GodotPlugin;
+import org.godotengine.godot.plugin.GodotPluginRegistry;
 import org.godotengine.godot.utils.GLUtils;
 
 /**
@@ -40,8 +43,13 @@ import org.godotengine.godot.utils.GLUtils;
  */
 class GodotRenderer implements GLSurfaceView.Renderer {
 
+	private final GodotPluginRegistry pluginRegistry;
 	private boolean activityJustResumed = false;
 
+	GodotRenderer() {
+		this.pluginRegistry = GodotPluginRegistry.getPluginRegistry();
+	}
+
 	public void onDrawFrame(GL10 gl) {
 		if (activityJustResumed) {
 			GodotLib.onRendererResumed();
@@ -49,21 +57,23 @@ class GodotRenderer implements GLSurfaceView.Renderer {
 		}
 
 		GodotLib.step();
-		for (int i = 0; i < Godot.singleton_count; i++) {
-			Godot.singletons[i].onGLDrawFrame(gl);
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onGLDrawFrame(gl);
 		}
 	}
 
 	public void onSurfaceChanged(GL10 gl, int width, int height) {
-
 		GodotLib.resize(width, height);
-		for (int i = 0; i < Godot.singleton_count; i++) {
-			Godot.singletons[i].onGLSurfaceChanged(gl, width, height);
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onGLSurfaceChanged(gl, width, height);
 		}
 	}
 
 	public void onSurfaceCreated(GL10 gl, EGLConfig config) {
 		GodotLib.newcontext(GLUtils.use_32);
+		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
+			plugin.onGLSurfaceCreated(gl, config);
+		}
 	}
 
 	void onActivityResumed() {
diff --git a/platform/android/java/lib/src/org/godotengine/godot/payments/GodotPaymentInterface.java b/platform/android/java/lib/src/org/godotengine/godot/payments/GodotPaymentInterface.java
new file mode 100644
index 0000000000..6ac7338b30
--- /dev/null
+++ b/platform/android/java/lib/src/org/godotengine/godot/payments/GodotPaymentInterface.java
@@ -0,0 +1,97 @@
+/*************************************************************************/
+/*  GodotPaymentInterface.java                                           */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+package org.godotengine.godot.payments;
+
+public interface GodotPaymentInterface {
+	void purchase(String sku, String transactionId);
+
+	void consumeUnconsumedPurchases();
+
+	String getSignature();
+
+	void callbackSuccess(String ticket, String signature, String sku);
+
+	void callbackSuccessProductMassConsumed(String ticket, String signature, String sku);
+
+	void callbackSuccessNoUnconsumedPurchases();
+
+	void callbackFailConsume(String message);
+
+	void callbackFail(String message);
+
+	void callbackCancel();
+
+	void callbackAlreadyOwned(String sku);
+
+	int getPurchaseCallbackId();
+
+	void setPurchaseCallbackId(int purchaseCallbackId);
+
+	String getPurchaseValidationUrlPrefix();
+
+	void setPurchaseValidationUrlPrefix(String url);
+
+	String getAccessToken();
+
+	void setAccessToken(String accessToken);
+
+	void setTransactionId(String transactionId);
+
+	String getTransactionId();
+
+	// request purchased items are not consumed
+	void requestPurchased();
+
+	// callback for requestPurchased()
+	void callbackPurchased(String receipt, String signature, String sku);
+
+	void callbackDisconnected();
+
+	void callbackConnected();
+
+	// true if connected, false otherwise
+	boolean isConnected();
+
+	// consume item automatically after purchase. default is true.
+	void setAutoConsume(boolean autoConsume);
+
+	// consume a specific item
+	void consume(String sku);
+
+	// query in app item detail info
+	void querySkuDetails(String[] list);
+
+	void addSkuDetail(String itemJson);
+
+	void completeSkuDetail();
+
+	void errorSkuDetail(String errorMessage);
+}
diff --git a/platform/android/java/lib/src/org/godotengine/godot/payments/PaymentsManager.java b/platform/android/java/lib/src/org/godotengine/godot/payments/PaymentsManager.java
index 90b958266b..9bf6650f84 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/payments/PaymentsManager.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/payments/PaymentsManager.java
@@ -43,7 +43,6 @@ import android.util.Log;
 import com.android.vending.billing.IInAppBillingService;
 import java.util.ArrayList;
 import java.util.Arrays;
-import org.godotengine.godot.GodotPaymentV3;
 import org.json.JSONException;
 import org.json.JSONObject;
 
@@ -90,9 +89,9 @@ public class PaymentsManager {
 		public void onServiceDisconnected(ComponentName name) {
 			mService = null;
 
-			// At this stage, godotPaymentV3 might not have been initialized yet.
-			if (godotPaymentV3 != null) {
-				godotPaymentV3.callbackDisconnected();
+			// At this stage, godotPayment might not have been initialized yet.
+			if (godotPayment != null) {
+				godotPayment.callbackDisconnected();
 			}
 		}
 
@@ -100,9 +99,9 @@ public class PaymentsManager {
 		public void onServiceConnected(ComponentName name, IBinder service) {
 			mService = IInAppBillingService.Stub.asInterface(service);
 
-			// At this stage, godotPaymentV3 might not have been initialized yet.
-			if (godotPaymentV3 != null) {
-				godotPaymentV3.callbackConnected();
+			// At this stage, godotPayment might not have been initialized yet.
+			if (godotPayment != null) {
+				godotPayment.callbackConnected();
 			}
 		}
 	};
@@ -111,17 +110,17 @@ public class PaymentsManager {
 		new PurchaseTask(mService, activity) {
 			@Override
 			protected void error(String message) {
-				godotPaymentV3.callbackFail(message);
+				godotPayment.callbackFail(message);
 			}
 
 			@Override
 			protected void canceled() {
-				godotPaymentV3.callbackCancel();
+				godotPayment.callbackCancel();
 			}
 
 			@Override
 			protected void alreadyOwned() {
-				godotPaymentV3.callbackAlreadyOwned(sku);
+				godotPayment.callbackAlreadyOwned(sku);
 			}
 		}
 				.purchase(sku, transactionId);
@@ -135,19 +134,19 @@ public class PaymentsManager {
 		new ReleaseAllConsumablesTask(mService, activity) {
 			@Override
 			protected void success(String sku, String receipt, String signature, String token) {
-				godotPaymentV3.callbackSuccessProductMassConsumed(receipt, signature, sku);
+				godotPayment.callbackSuccessProductMassConsumed(receipt, signature, sku);
 			}
 
 			@Override
 			protected void error(String message) {
 				Log.d("godot", "consumeUnconsumedPurchases :" + message);
-				godotPaymentV3.callbackFailConsume(message);
+				godotPayment.callbackFailConsume(message);
 			}
 
 			@Override
 			protected void notRequired() {
 				Log.d("godot", "callbackSuccessNoUnconsumedPurchases :");
-				godotPaymentV3.callbackSuccessNoUnconsumedPurchases();
+				godotPayment.callbackSuccessNoUnconsumedPurchases();
 			}
 		}
 				.consumeItAll();
@@ -168,7 +167,7 @@ public class PaymentsManager {
 					final ArrayList<String> mySignatures = bundle.getStringArrayList("INAPP_DATA_SIGNATURE_LIST");
 
 					if (myPurchases == null || myPurchases.size() == 0) {
-						godotPaymentV3.callbackPurchased("", "", "");
+						godotPayment.callbackPurchased("", "", "");
 						return;
 					}
 
@@ -186,7 +185,7 @@ public class PaymentsManager {
 							pc.setConsumableFlag("block", sku, true);
 							pc.setConsumableValue("token", sku, token);
 
-							godotPaymentV3.callbackPurchased(receipt, signature, sku);
+							godotPayment.callbackPurchased(receipt, signature, sku);
 						} catch (JSONException e) {
 						}
 					}
@@ -203,7 +202,7 @@ public class PaymentsManager {
 		new HandlePurchaseTask(activity) {
 			@Override
 			protected void success(final String sku, final String signature, final String ticket) {
-				godotPaymentV3.callbackSuccess(ticket, signature, sku);
+				godotPayment.callbackSuccess(ticket, signature, sku);
 
 				if (auto_consume) {
 					new ConsumeTask(mService, activity) {
@@ -213,7 +212,7 @@ public class PaymentsManager {
 
 						@Override
 						protected void error(String message) {
-							godotPaymentV3.callbackFail(message);
+							godotPayment.callbackFail(message);
 						}
 					}
 							.consume(sku);
@@ -222,12 +221,12 @@ public class PaymentsManager {
 
 			@Override
 			protected void error(String message) {
-				godotPaymentV3.callbackFail(message);
+				godotPayment.callbackFail(message);
 			}
 
 			@Override
 			protected void canceled() {
-				godotPaymentV3.callbackCancel();
+				godotPayment.callbackCancel();
 			}
 		}
 				.handlePurchaseRequest(resultCode, data);
@@ -235,19 +234,19 @@ public class PaymentsManager {
 
 	public void validatePurchase(String purchaseToken, final String sku) {
 
-		new ValidateTask(activity, godotPaymentV3) {
+		new ValidateTask(activity, godotPayment) {
 			@Override
 			protected void success() {
 
 				new ConsumeTask(mService, activity) {
 					@Override
 					protected void success(String ticket) {
-						godotPaymentV3.callbackSuccess(ticket, null, sku);
+						godotPayment.callbackSuccess(ticket, null, sku);
 					}
 
 					@Override
 					protected void error(String message) {
-						godotPaymentV3.callbackFail(message);
+						godotPayment.callbackFail(message);
 					}
 				}
 						.consume(sku);
@@ -255,12 +254,12 @@ public class PaymentsManager {
 
 			@Override
 			protected void error(String message) {
-				godotPaymentV3.callbackFail(message);
+				godotPayment.callbackFail(message);
 			}
 
 			@Override
 			protected void canceled() {
-				godotPaymentV3.callbackCancel();
+				godotPayment.callbackCancel();
 			}
 		}
 				.validatePurchase(sku);
@@ -274,12 +273,12 @@ public class PaymentsManager {
 		new ConsumeTask(mService, activity) {
 			@Override
 			protected void success(String ticket) {
-				godotPaymentV3.callbackSuccessProductMassConsumed(ticket, "", sku);
+				godotPayment.callbackSuccessProductMassConsumed(ticket, "", sku);
 			}
 
 			@Override
 			protected void error(String message) {
-				godotPaymentV3.callbackFailConsume(message);
+				godotPayment.callbackFailConsume(message);
 			}
 		}
 				.consume(sku);
@@ -387,9 +386,9 @@ public class PaymentsManager {
 						if (!skuDetails.containsKey("DETAILS_LIST")) {
 							int response = getResponseCodeFromBundle(skuDetails);
 							if (response != BILLING_RESPONSE_RESULT_OK) {
-								godotPaymentV3.errorSkuDetail(getResponseDesc(response));
+								godotPayment.errorSkuDetail(getResponseDesc(response));
 							} else {
-								godotPaymentV3.errorSkuDetail("No error but no detail list.");
+								godotPayment.errorSkuDetail("No error but no detail list.");
 							}
 							return;
 						}
@@ -398,22 +397,22 @@ public class PaymentsManager {
 
 						for (String thisResponse : responseList) {
 							Log.d("godot", "response = " + thisResponse);
-							godotPaymentV3.addSkuDetail(thisResponse);
+							godotPayment.addSkuDetail(thisResponse);
 						}
 					} catch (RemoteException e) {
 						e.printStackTrace();
-						godotPaymentV3.errorSkuDetail("RemoteException error!");
+						godotPayment.errorSkuDetail("RemoteException error!");
 					}
 				}
-				godotPaymentV3.completeSkuDetail();
+				godotPayment.completeSkuDetail();
 			}
 		}))
 				.start();
 	}
 
-	private GodotPaymentV3 godotPaymentV3;
+	private GodotPaymentInterface godotPayment;
 
-	public void setBaseSingleton(GodotPaymentV3 godotPaymentV3) {
-		this.godotPaymentV3 = godotPaymentV3;
+	public void setBaseSingleton(GodotPaymentInterface godotPaymentInterface) {
+		this.godotPayment = godotPaymentInterface;
 	}
 }
diff --git a/platform/android/java/lib/src/org/godotengine/godot/payments/ValidateTask.java b/platform/android/java/lib/src/org/godotengine/godot/payments/ValidateTask.java
index dbb6b8a783..10c314aecf 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/payments/ValidateTask.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/payments/ValidateTask.java
@@ -34,7 +34,6 @@ import android.app.Activity;
 import android.app.ProgressDialog;
 import android.os.AsyncTask;
 import java.lang.ref.WeakReference;
-import org.godotengine.godot.GodotPaymentV3;
 import org.godotengine.godot.utils.HttpRequester;
 import org.godotengine.godot.utils.RequestParams;
 import org.json.JSONException;
@@ -43,7 +42,7 @@ import org.json.JSONObject;
 abstract public class ValidateTask {
 
 	private Activity context;
-	private GodotPaymentV3 godotPaymentsV3;
+	private GodotPaymentInterface godotPayments;
 	private ProgressDialog dialog;
 	private String mSku;
 
@@ -80,9 +79,9 @@ abstract public class ValidateTask {
 		}
 	}
 
-	public ValidateTask(Activity context, GodotPaymentV3 godotPaymentsV3) {
+	public ValidateTask(Activity context, GodotPaymentInterface godotPayments) {
 		this.context = context;
-		this.godotPaymentsV3 = godotPaymentsV3;
+		this.godotPayments = godotPayments;
 	}
 
 	public void validatePurchase(final String sku) {
@@ -96,7 +95,7 @@ abstract public class ValidateTask {
 
 	private String doInBackground(String... params) {
 		PaymentsCache pc = new PaymentsCache(context);
-		String url = godotPaymentsV3.getPurchaseValidationUrlPrefix();
+		String url = godotPayments.getPurchaseValidationUrlPrefix();
 		RequestParams param = new RequestParams();
 		param.setUrl(url);
 		param.put("ticket", pc.getConsumableValue("ticket", mSku));
diff --git a/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
new file mode 100644
index 0000000000..d5bf4fc70e
--- /dev/null
+++ b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
@@ -0,0 +1,256 @@
+/*************************************************************************/
+/*  GodotPlugin.java                                                     */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+package org.godotengine.godot.plugin;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.view.View;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.opengles.GL10;
+import org.godotengine.godot.Godot;
+
+/**
+ * Base class for the Godot Android plugins.
+ * <p>
+ * A Godot Android plugin is a regular Android library packaged as an aar archive file with the following caveats:
+ * <p>
+ * - The library must have a dependency on the Godot Android library (godot-lib.aar).
+ * A stable version is available for each release.
+ * <p>
+ * - The library must include a <meta-data> tag in its manifest file setup as follow:
+ * <meta-data android:name="org.godotengine.plugin.v1.[PluginName]" android:value="[plugin.init.ClassFullName]" />
+ * Where:
+ * - 'PluginName' is the name of the plugin.
+ * - 'plugin.init.ClassFullName' is the full name (package + class name) of the plugin class
+ * extending {@link GodotPlugin}.
+ *
+ * A plugin can also define and provide c/c++ gdnative libraries and nativescripts for the target
+ * app/game to leverage.
+ * The shared library for the gdnative library will be automatically bundled by the aar build
+ * system.
+ * Godot '*.gdnlib' and '*.gdns' resource files must however be manually defined in the project
+ * 'assets' directory. The recommended path for these resources in the 'assets' directory should be:
+ * 'godot/plugin/v1/[PluginName]/'
+ */
+public abstract class GodotPlugin {
+
+	private final Godot godot;
+
+	public GodotPlugin(Godot godot) {
+		this.godot = godot;
+	}
+
+	/**
+	 * Provides access to the Godot engine.
+	 */
+	protected Godot getGodot() {
+		return godot;
+	}
+
+	/**
+	 * Register the plugin with Godot native code.
+	 */
+	public final void onGLRegisterPluginWithGodotNative() {
+		nativeRegisterSingleton(getPluginName());
+
+		Class clazz = getClass();
+		Method[] methods = clazz.getDeclaredMethods();
+		for (Method method : methods) {
+			boolean found = false;
+
+			for (String s : getPluginMethods()) {
+				if (s.equals(method.getName())) {
+					found = true;
+					break;
+				}
+			}
+			if (!found)
+				continue;
+
+			List<String> ptr = new ArrayList<String>();
+
+			Class[] paramTypes = method.getParameterTypes();
+			for (Class c : paramTypes) {
+				ptr.add(c.getName());
+			}
+
+			String[] pt = new String[ptr.size()];
+			ptr.toArray(pt);
+
+			nativeRegisterMethod(getPluginName(), method.getName(), method.getReturnType().getName(), pt);
+		}
+
+		// Get the list of gdnative libraries to register.
+		Set<String> gdnativeLibrariesPaths = getPluginGDNativeLibrariesPaths();
+		if (!gdnativeLibrariesPaths.isEmpty()) {
+			nativeRegisterGDNativeLibraries(gdnativeLibrariesPaths.toArray(new String[0]));
+		}
+	}
+
+	/**
+	 * Invoked once during the Godot Android initialization process after creation of the
+	 * {@link org.godotengine.godot.GodotView} view.
+	 * <p>
+	 * This method should be overridden by descendants of this class that would like to add
+	 * their view/layout to the Godot view hierarchy.
+	 *
+	 * @return the view to be included; null if no views should be included.
+	 */
+	@Nullable
+	public View onMainCreateView(Activity activity) {
+		return null;
+	}
+
+	/**
+	 * @see Activity#onActivityResult(int, int, Intent)
+	 */
+	public void onMainActivityResult(int requestCode, int resultCode, Intent data) {
+	}
+
+	/**
+	 * @see Activity#onRequestPermissionsResult(int, String[], int[])
+	 */
+	public void onMainRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
+	}
+
+	/**
+	 * @see Activity#onPause()
+	 */
+	public void onMainPause() {}
+
+	/**
+	 * @see Activity#onResume()
+	 */
+	public void onMainResume() {}
+
+	/**
+	 * @see Activity#onDestroy()
+	 */
+	public void onMainDestroy() {}
+
+	/**
+	 * @see Activity#onBackPressed()
+	 */
+	public boolean onMainBackPressed() { return false; }
+
+	/**
+	 * Invoked on the GL thread when the Godot main loop has started.
+	 */
+	public void onGLGodotMainLoopStarted() {}
+
+	/**
+	 * Invoked once per frame on the GL thread after the frame is drawn.
+	 */
+	public void onGLDrawFrame(GL10 gl) {}
+
+	/**
+	 * Called on the GL thread after the surface is created and whenever the OpenGL ES surface size
+	 * changes.
+	 */
+	public void onGLSurfaceChanged(GL10 gl, int width, int height) {}
+
+	/**
+	 * Called on the GL thread when the surface is created or recreated.
+	 */
+	public void onGLSurfaceCreated(GL10 gl, EGLConfig config) {}
+
+	/**
+	 * Returns the name of the plugin.
+	 * <p>
+	 * This value must match the one listed in the plugin '<meta-data>' manifest entry.
+	 */
+	@NonNull
+	public abstract String getPluginName();
+
+	/**
+	 * Returns the list of methods to be exposed to Godot.
+	 */
+	@NonNull
+	public abstract List<String> getPluginMethods();
+
+	/**
+	 * Returns the paths for the plugin's gdnative libraries.
+	 *
+	 * The paths must be relative to the 'assets' directory and point to a '*.gdnlib' file.
+	 */
+	@NonNull
+	protected Set<String> getPluginGDNativeLibrariesPaths() {
+		return Collections.emptySet();
+	}
+
+	/**
+	 * Runs the specified action on the UI thread. If the current thread is the UI
+	 * thread, then the action is executed immediately. If the current thread is
+	 * not the UI thread, the action is posted to the event queue of the UI thread.
+	 *
+	 * @param action the action to run on the UI thread
+	 */
+	protected void runOnUiThread(Runnable action) {
+		godot.runOnUiThread(action);
+	}
+
+	/**
+	 * Queue the specified action to be run on the GL thread.
+	 *
+	 * @param action the action to run on the GL thread
+	 */
+	protected void runOnGLThread(Runnable action) {
+		godot.runOnGLThread(action);
+	}
+
+	/**
+	 * Used to setup a {@link GodotPlugin} instance.
+	 * @param p_name Name of the instance.
+	 */
+	private native void nativeRegisterSingleton(String p_name);
+
+	/**
+	 * Used to complete registration of the {@link GodotPlugin} instance's methods.
+	 * @param p_sname Name of the instance
+	 * @param p_name Name of the method to register
+	 * @param p_ret Return type of the registered method
+	 * @param p_params Method parameters types
+	 */
+	private native void nativeRegisterMethod(String p_sname, String p_name, String p_ret, String[] p_params);
+
+	/**
+	 * Used to register gdnative libraries bundled by the plugin.
+	 * @param gdnlibPaths Paths to the libraries relative to the 'assets' directory.
+	 */
+	private native void nativeRegisterGDNativeLibraries(String[] gdnlibPaths);
+}
diff --git a/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPluginRegistry.java b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPluginRegistry.java
new file mode 100644
index 0000000000..3562920182
--- /dev/null
+++ b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPluginRegistry.java
@@ -0,0 +1,196 @@
+/*************************************************************************/
+/*  GodotPluginRegistry.java                                             */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+package org.godotengine.godot.plugin;
+
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.text.TextUtils;
+import android.util.Log;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import org.godotengine.godot.Godot;
+
+/**
+ * Registry used to load and access the registered Godot Android plugins.
+ */
+public final class GodotPluginRegistry {
+
+	private static final String TAG = GodotPluginRegistry.class.getSimpleName();
+
+	private static final String GODOT_PLUGIN_V1_NAME_PREFIX = "org.godotengine.plugin.v1.";
+
+	/**
+	 * Name for the metadata containing the list of Godot plugins to enable.
+	 */
+	private static final String GODOT_ENABLED_PLUGINS_LABEL = "custom_template_plugins";
+
+	private static GodotPluginRegistry instance;
+	private final ConcurrentHashMap<String, GodotPlugin> registry;
+
+	private GodotPluginRegistry(Godot godot) {
+		registry = new ConcurrentHashMap<>();
+		loadPlugins(godot);
+	}
+
+	/**
+	 * Retrieve the plugin tied to the given plugin name.
+	 * @param pluginName Name of the plugin
+	 * @return {@link GodotPlugin} handle if it exists, null otherwise.
+	 */
+	@Nullable
+	public GodotPlugin getPlugin(String pluginName) {
+		return registry.get(pluginName);
+	}
+
+	/**
+	 * Retrieve the full set of loaded plugins.
+	 */
+	public Collection<GodotPlugin> getAllPlugins() {
+		return registry.values();
+	}
+
+	/**
+	 * Parse the manifest file and load all included Godot Android plugins.
+	 * <p>
+	 * A plugin manifest entry is a '<meta-data>' tag setup as described in the {@link GodotPlugin}
+	 * documentation.
+	 *
+	 * @param godot Godot instance
+	 * @return A singleton instance of {@link GodotPluginRegistry}. This ensures that only one instance
+	 * of each Godot Android plugins is available at runtime.
+	 */
+	public static GodotPluginRegistry initializePluginRegistry(Godot godot) {
+		if (instance == null) {
+			instance = new GodotPluginRegistry(godot);
+		}
+
+		return instance;
+	}
+
+	/**
+	 * Return the plugin registry if it's initialized.
+	 * Throws a {@link IllegalStateException} exception if not.
+	 *
+	 * @throws IllegalStateException if {@link GodotPluginRegistry#initializePluginRegistry(Godot)} has not been called prior to calling this method.
+	 */
+	public static GodotPluginRegistry getPluginRegistry() throws IllegalStateException {
+		if (instance == null) {
+			throw new IllegalStateException("Plugin registry hasn't been initialized.");
+		}
+
+		return instance;
+	}
+
+	private void loadPlugins(Godot godot) {
+		try {
+			ApplicationInfo appInfo = godot
+											  .getPackageManager()
+											  .getApplicationInfo(godot.getPackageName(), PackageManager.GET_META_DATA);
+			Bundle metaData = appInfo.metaData;
+			if (metaData == null || metaData.isEmpty()) {
+				return;
+			}
+
+			// When using the Godot editor for building and exporting the apk, this is used to check
+			// which plugins to enable since the custom build template may contain prebuilt plugins.
+			// When using a custom process to generate the apk, the metadata is not needed since
+			// it's assumed that the developer is aware of the dependencies included in the apk.
+			final Set<String> enabledPluginsSet;
+			if (metaData.containsKey(GODOT_ENABLED_PLUGINS_LABEL)) {
+				String enabledPlugins = metaData.getString(GODOT_ENABLED_PLUGINS_LABEL, "");
+				String[] enabledPluginsList = enabledPlugins.split(",");
+				if (enabledPluginsList.length == 0) {
+					// No plugins to enable. Aborting early.
+					return;
+				}
+
+				enabledPluginsSet = new HashSet<>(Arrays.asList(enabledPluginsList));
+			} else {
+				enabledPluginsSet = null;
+			}
+
+			int godotPluginV1NamePrefixLength = GODOT_PLUGIN_V1_NAME_PREFIX.length();
+			for (String metaDataName : metaData.keySet()) {
+				// Parse the meta-data looking for entry with the Godot plugin name prefix.
+				if (metaDataName.startsWith(GODOT_PLUGIN_V1_NAME_PREFIX)) {
+					String pluginName = metaDataName.substring(godotPluginV1NamePrefixLength);
+					if (enabledPluginsSet != null && !enabledPluginsSet.contains(pluginName)) {
+						Log.w(TAG, "Plugin " + pluginName + " is listed in the dependencies but is not enabled.");
+						continue;
+					}
+
+					// Retrieve the plugin class full name.
+					String pluginHandleClassFullName = metaData.getString(metaDataName);
+					if (!TextUtils.isEmpty(pluginHandleClassFullName)) {
+						try {
+							// Attempt to create the plugin init class via reflection.
+							@SuppressWarnings("unchecked")
+							Class<GodotPlugin> pluginClass = (Class<GodotPlugin>)Class
+																	 .forName(pluginHandleClassFullName);
+							Constructor<GodotPlugin> pluginConstructor = pluginClass
+																				 .getConstructor(Godot.class);
+							GodotPlugin pluginHandle = pluginConstructor.newInstance(godot);
+
+							// Load the plugin initializer into the registry using the plugin name
+							// as key.
+							if (!pluginName.equals(pluginHandle.getPluginName())) {
+								Log.w(TAG,
+										"Meta-data plugin name does not match the value returned by the plugin handle: " + pluginName + " =/= " + pluginHandle.getPluginName());
+							}
+							registry.put(pluginName, pluginHandle);
+						} catch (ClassNotFoundException e) {
+							Log.w(TAG, "Unable to load Godot plugin " + pluginName, e);
+						} catch (IllegalAccessException e) {
+							Log.w(TAG, "Unable to load Godot plugin " + pluginName, e);
+						} catch (InstantiationException e) {
+							Log.w(TAG, "Unable to load Godot plugin " + pluginName, e);
+						} catch (NoSuchMethodException e) {
+							Log.w(TAG, "Unable to load Godot plugin " + pluginName, e);
+						} catch (InvocationTargetException e) {
+							Log.w(TAG, "Unable to load Godot plugin " + pluginName, e);
+						}
+					} else {
+						Log.w(TAG, "Invalid plugin loader class for " + pluginName);
+					}
+				}
+			}
+		} catch (PackageManager.NameNotFoundException e) {
+			Log.e(TAG, "Unable load Godot Android plugins from the manifest file.", e);
+		}
+	}
+}