Don't add the same point twice when splitting touch events by subscene

A point might have an exclusive grabber and multiple passive grabbers.
It could be that different grabbers are in different subscenes; but in
the case that there is both a passive and an exclusive grabber in one
subscene, QQuickWindow::event() calls the inline insert() function
multiple times with the same point and same DeliveryAgent, but we must
not add it to the QList more than once.  (It could even be a QSet
instead of a QList, but that might not be optimal, and would disrupt the
order of EventPoints FWIW... not that we normally guarantee order.
And afterwards we pass the QList to the QMutableTouchEvent ctor taking
QList<QEventPoint>, so it's just as well to have it built already.)

This helps to fix the tst_Input::dualTouchTap2D test in Qt Quick 3D:
if you press one finger on a MouseArea in the left subscene and one
on an MA in the right subscene, and then release, we do not want to
give two copies of the left eventpoint to the left subscene, because
then QQuickDeliveryAgentPrivate::deliverPointerEvent() will actually
store into originalScenePositions a copy of the scene position that has
already been through the sceneTransform->map(), and restore it
afterwards. That results in the synth-mouse event getting the wrong
position, and the test fails because the press and release positions
don't match.

Amends 5c08e911375966761ee8e4d7cd425120985876e2

Change-Id: I856b676b5c66b59ed20c4a5e395e6e66478438da
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit 82bf2eeb341ecc6b252e7a575bed8bf4bd329e96)

1 files changed, 6 insertions, 1 deletions

diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index 6d602a3810..c3fd4560d2 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -1370,7 +1370,12 @@ bool QQuickWindow::event(QEvent *e)
                     if (danpit == deliveryAgentsNeedingPoints.end()) {
                         deliveryAgentsNeedingPoints.insert(ptda, QList<QEventPoint>() << pt);
                     } else {
-                        danpit.value().append(pt);
+                        auto &ptList = danpit.value();
+                        auto ptid = pt.id();
+                        auto alreadyThere = std::find_if(ptList.constBegin(), ptList.constEnd(),
+                            [ptid] (const QEventPoint &pep) { return pep.id() == ptid; });
+                        if (alreadyThere == ptList.constEnd())
+                            danpit.value().append(pt);
                     }
                 };