Restore scene position after changing it during delivery

When we visit multiple subscenes via multiple DAs, if they are changing
the scene pos, the original gets lost, and then maybe we visit some
handler via the root DA again (like a TapHandler declared in a View3D).

This helps to fix qtquick3d/examples/quick3d/dynamictexture

Task-number: QTBUG-92944
Pick-to: 6.1
Change-Id: I9bd8cfc2510168b6e14002957833b54eb9586ab0
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/quick/util/qquickdeliveryagent.cpp b/src/quick/util/qquickdeliveryagent.cpp
index 651aa598d8..45a7afda47 100644
--- a/src/quick/util/qquickdeliveryagent.cpp
+++ b/src/quick/util/qquickdeliveryagent.cpp
@@ -1519,9 +1519,12 @@ void QQuickDeliveryAgentPrivate::deliverPointerEvent(QPointerEvent *event)
     // updates get delivered here pretty directly, bypassing picking; but we need to
     // be able to map the 2D viewport coordinate to a 2D coordinate within
     // d->rootItem, a 2D scene that has been arbitrarily mapped onto a 3D object.
+    QVarLengthArray<QPointF, 16> originalScenePositions;
     if (sceneTransform) {
+        originalScenePositions.resize(event->pointCount());
         for (int i = 0; i < event->pointCount(); ++i) {
             auto &mut = QMutableEventPoint::from(event->point(i));
+            originalScenePositions[i] = mut.scenePosition();
             mut.setScenePosition(sceneTransform->map(mut.scenePosition()));
             qCDebug(lcPtrLoc) << q << event->type() << mut.id() << "transformed scene pos" << mut.scenePosition();
         }
@@ -1571,6 +1574,10 @@ void QQuickDeliveryAgentPrivate::deliverPointerEvent(QPointerEvent *event)
     }
 
     eventsInDelivery.pop();
+    if (sceneTransform) {
+        for (int i = 0; i < event->pointCount(); ++i)
+            QMutableEventPoint::from(event->point(i)).setScenePosition(originalScenePositions.at(i));
+    }
     --pointerEventRecursionGuard;
     lastUngrabbed = nullptr;
 }