Engine::unprotected() drops the command queue back to unprotected mode

FIXES=[344021154]

android/filament-android/src/main/cpp/Engine.cpp

@@ -420,6 +420,13 @@ Java_com_google_android_filament_Engine_nSetPaused(JNIEnv*, jclass,
     engine->setPaused(paused);
 }
 
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_Engine_nUnprotected(JNIEnv*, jclass,
+        jlong nativeEngine, jboolean paused) {
+    Engine* engine = (Engine*) nativeEngine;
+    engine->unprotected();
+}
+
 // Managers...
 
 extern "C" JNIEXPORT jlong JNICALL

android/filament-android/src/main/java/com/google/android/filament/Engine.java

@@ -1289,6 +1289,18 @@ public class Engine {
         nSetPaused(getNativeObject(), paused);
     }
 
+    /**
+     * Switch the command queue to unprotected mode. Protected mode can be activated via
+     * Renderer::beginFrame() using a protected SwapChain.
+
+     * @see Renderer
+     * @see SwapChain
+     */
+    public void unprotected() {
+        nUnprotected(getNativeObject());
+    }
+
+
     @UsedByReflection("TextureHelper.java")
     public long getNativeObject() {
         if (mNativeObject == 0) {
@@ -1366,6 +1378,7 @@ public class Engine {
     private static native void nFlush(long nativeEngine);
     private static native boolean nIsPaused(long nativeEngine);
     private static native void nSetPaused(long nativeEngine, boolean paused);
+    private static native void nUnprotected(long nativeEngine);
     private static native long nGetTransformManager(long nativeEngine);
     private static native long nGetLightManager(long nativeEngine);
     private static native long nGetRenderableManager(long nativeEngine);

filament/include/filament/Engine.h

@@ -930,6 +930,14 @@ public:
      */
     void pumpMessageQueues();
 
+    /**
+     * Switch the command queue to unprotected mode. Protected mode can be activated via
+     * Renderer::beginFrame() using a protected SwapChain.
+     * @see Renderer
+     * @see SwapChain
+     */
+    void unprotected() noexcept;
+
     /**
      * Returns the default Material.
      *

filament/src/Engine.cpp

@@ -329,6 +329,10 @@ void Engine::pumpMessageQueues() {
     downcast(this)->pumpMessageQueues();
 }
 
+void Engine::unprotected() noexcept {
+    downcast(this)->unprotected();
+}
+
 void Engine::setAutomaticInstancingEnabled(bool enable) noexcept {
     downcast(this)->setAutomaticInstancingEnabled(enable);
 }

filament/src/details/Engine.cpp

@@ -476,6 +476,8 @@ void FEngine::shutdown() {
 
     destroy(mDefaultMaterial);
 
+    destroy(mUnprotectedDummySwapchain);
+
     /*
      * clean-up after the user -- we call terminate on each "leaked" object and clear each list.
      *
@@ -1253,6 +1255,13 @@ void FEngine::resetBackendState() noexcept {
 }
 #endif
 
+void FEngine::unprotected() noexcept {
+    if (UTILS_UNLIKELY(!mUnprotectedDummySwapchain)) {
+        mUnprotectedDummySwapchain = createSwapChain(1, 1, 0);
+    }
+    mUnprotectedDummySwapchain->makeCurrent(getDriverApi());
+}
+
 // ------------------------------------------------------------------------------------------------
 
 Engine::Builder::Builder() noexcept = default;

filament/src/details/Engine.h

@@ -406,6 +406,8 @@ public:
         getDriver().purge();
     }
 
+    void unprotected() noexcept;
+
     void setAutomaticInstancingEnabled(bool enable) noexcept {
         // instancing is not allowed at feature level 0
         if (hasFeatureLevel(FeatureLevel::FEATURE_LEVEL_1)) {
@@ -539,6 +541,7 @@ private:
 
     mutable FMaterial const* mDefaultMaterial = nullptr;
     mutable FMaterial const* mSkyboxMaterial = nullptr;
+    mutable FSwapChain* mUnprotectedDummySwapchain = nullptr;
 
     mutable FTexture* mDefaultIblTexture = nullptr;
     mutable FIndirectLight* mDefaultIbl = nullptr;

web/filament-js/jsbindings.cpp

@@ -388,6 +388,8 @@ class_<Engine>("Engine")
         return Engine::create();
     }, allow_raw_pointers())
 
+    .function("unprotected", &Engine::unprotected)
+
     .function("enableAccurateTranslations", &Engine::enableAccurateTranslations)
 
     .function("setAutomaticInstancingEnabled", &Engine::setAutomaticInstancingEnabled)