Fix two sources of crashes when (un)loading a Studio3D

Task-number: QT3DS-1995
Change-Id: Ie9a5ded67edba5d9c0247fb381254558e381bf3a
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/imports/studio3d/q3dsstudio3ditem.cpp b/src/imports/studio3d/q3dsstudio3ditem.cpp
index eded414..4bf64e8 100644
--- a/src/imports/studio3d/q3dsstudio3ditem.cpp
+++ b/src/imports/studio3d/q3dsstudio3ditem.cpp
@@ -459,7 +459,10 @@ void Q3DSStudio3DItem::itemChange(QQuickItem::ItemChange change,
 void Q3DSStudio3DItem::startEngine()
 {
     // set root entity
-    m_engine->start();
+    if (m_engine)
+        m_engine->start();
+    else
+        qWarning("No engine (no window for item?), cannot start");
 }
 
 void Q3DSStudio3DItem::destroyEngine()
@@ -548,6 +551,7 @@ void Q3DSStudio3DItem::releaseEngineAndRenderer()
         EngineReleaser *er = new EngineReleaser(m_engine);
         RendererReleaser *rr = new RendererReleaser(m_renderer, er);
         window()->scheduleRenderJob(rr, QQuickWindow::BeforeSynchronizingStage);
+        m_renderer->invalidateItem();
         m_renderer = nullptr;
         m_engine = nullptr;
     }