Attempting to fix threading issues with web entities

interface/src/Application.cpp

@@ -341,6 +341,7 @@ Application::Application(int& argc, char** argv, QElapsedTimer &startup_time) :
         _domainConnectionRefusals(QList<QString>()),
         _maxOctreePPS(maxOctreePacketsPerSecond.get())
 {
+    setInstance(this);
 #ifdef Q_OS_WIN
     installNativeEventFilter(&MyNativeEventFilter::getInstance());
 #endif
@@ -4694,7 +4695,3 @@ qreal Application::getDevicePixelRatio() {
     return _window ? _window->windowHandle()->devicePixelRatio() : 1.0;
 }
 
-
-AbstractViewStateInterface* AbstractViewStateInterface::instance() {
-    return qApp;
-}

libraries/entities-renderer/src/RenderableWebEntityItem.cpp

@@ -33,13 +33,15 @@ EntityItem* RenderableWebEntityItem::factory(const EntityItemID& entityID, const
 
 RenderableWebEntityItem::RenderableWebEntityItem(const EntityItemID& entityItemID, const EntityItemProperties& properties) :
     WebEntityItem(entityItemID, properties) {
+    qDebug() << "Created web entity " << getID();
 }
 
 RenderableWebEntityItem::~RenderableWebEntityItem() {
     if (_webSurface) {
         _webSurface->pause();
         _webSurface->disconnect(_connection);
-        // After the disconnect, ensure that we have the latest
+        // After the disconnect, ensure that we have the latest texture by acquiring the 
+        // lock used when updating the _texture value
         _textureLock.lock();
         _textureLock.unlock();
         // The lifetime of the QML surface MUST be managed by the main thread
@@ -55,6 +57,7 @@ RenderableWebEntityItem::~RenderableWebEntityItem() {
             webSurface->deleteLater();
         });
     }
+    qDebug() << "Destroyed web entity " << getID();
 }
 
 void RenderableWebEntityItem::render(RenderArgs* args) {
@@ -66,7 +69,7 @@ void RenderableWebEntityItem::render(RenderArgs* args) {
         _webSurface->setBaseUrl(QUrl::fromLocalFile(PathUtils::resourcesPath() + "/qml/"));
         _webSurface->load("WebEntity.qml");
         _webSurface->resume();
-        updateQmlSourceUrl();
+        _webSurface->getRootItem()->setProperty("url", _sourceUrl);
         _connection = QObject::connect(_webSurface, &OffscreenQmlSurface::textureUpdated, [&](GLuint textureId) {
             _webSurface->lockTexture(textureId);
             assert(!glGetError());
@@ -135,24 +138,10 @@ void RenderableWebEntityItem::render(RenderArgs* args) {
 void RenderableWebEntityItem::setSourceUrl(const QString& value) {
     if (_sourceUrl != value) {
         _sourceUrl = value;
-        AbstractViewStateInterface::instance()->postLambdaEvent([this] {
-            // Update the offscreen display
-            updateQmlSourceUrl();
-        });
+        if (_webSurface) {
+            AbstractViewStateInterface::instance()->postLambdaEvent([this] {
+                _webSurface->getRootItem()->setProperty("url", _sourceUrl);
+            });
+        }
     }
 }
-
-void RenderableWebEntityItem::updateQmlSourceUrl() {
-    if (!_webSurface) {
-        return;
-    }
-    auto webView = _webSurface->getRootItem();
-    if (!webView) {
-        return;
-    }
-    if (!_sourceUrl.isEmpty()) {
-        webView->setProperty("url", _sourceUrl);
-    } else {
-        webView->setProperty("url", QVariant());
-    }
-}

libraries/entities-renderer/src/RenderableWebEntityItem.h

@@ -26,9 +26,7 @@ public:
     virtual void setSourceUrl(const QString& value);
 
 private:
-    void updateQmlSourceUrl();
-
-    OffscreenQmlSurface* _webSurface;
+    OffscreenQmlSurface* _webSurface{ nullptr };
     QMetaObject::Connection _connection;
     uint32_t _texture{ 0 };
     QMutex _textureLock;

libraries/render-utils/src/AbstractViewStateInterface.cpp

@@ -0,0 +1,20 @@
+//
+//  Created by Bradley Austin Davis 2015/05/13
+//  Copyright 2014 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#include "AbstractViewStateInterface.h"
+
+static AbstractViewStateInterface* INSTANCE{nullptr};
+
+AbstractViewStateInterface* AbstractViewStateInterface::instance() {
+    return INSTANCE;
+}
+
+void AbstractViewStateInterface::setInstance(AbstractViewStateInterface* instance) {
+    INSTANCE = instance;
+}
+

libraries/render-utils/src/AbstractViewStateInterface.h

@@ -15,6 +15,8 @@
 #include <glm/glm.hpp>
 #include <functional>
 
+#include <QtGlobal>
+
 class Transform;
 class QThread;
 class ViewFrustum;
@@ -59,6 +61,7 @@ public:
     virtual qreal getDevicePixelRatio() = 0;
 
     static AbstractViewStateInterface* instance();
+    static void setInstance(AbstractViewStateInterface* instance);
 };