Fix screen position based queries in threaded rendering environment

QtQuick's threaded renderer doesn't seem to always pair up sync and
render (or more accurately, beforeSynchronizing and node's
preprocess calls). Sometimes sync comes without a followup render,
or there are two syncs in a row, even though the sync is using
direct connection. Both of these cases broke the old
logic for handling position based queries.

Changed the logic to actually ensure we have resolved the query
before emitting the relevant signal.

Task-number: QTRD-3358
Change-Id: Ica6c8c311f53a06311c21532aaabc18c28556655
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

1 files changed, 19 insertions, 8 deletions

diff --git a/src/datavisualization/engine/abstract3dcontroller.cpp b/src/datavisualization/engine/abstract3dcontroller.cpp
index 27d01029..f8a1a813 100644
--- a/src/datavisualization/engine/abstract3dcontroller.cpp
+++ b/src/datavisualization/engine/abstract3dcontroller.cpp
@@ -170,16 +170,14 @@ void Abstract3DController::synchDataToRenderer()
 {
     // Subclass implementations check for renderer validity already, so no need to check here.
 
+    m_renderPending = false;
+
     // If there are pending queries, handle those first
-    if (m_renderer->isGraphPositionQueryPending()) {
+    if (m_renderer->isGraphPositionQueryResolved())
         handlePendingGraphPositionQuery();
-        m_renderer->clearGraphPositionQueryPending();
-    }
 
-    if (m_renderer->isClickPending()) {
+    if (m_renderer->isClickQueryResolved())
         handlePendingClick();
-        m_renderer->clearClickPending();
-    }
 
     startRecordingRemovesAndInserts();
 
@@ -518,8 +516,6 @@ void Abstract3DController::synchDataToRenderer()
 
 void Abstract3DController::render(const GLuint defaultFboHandle)
 {
-    m_renderPending = false;
-
     // If not initialized, do nothing.
     if (!m_renderer)
         return;
@@ -1489,12 +1485,27 @@ void Abstract3DController::handlePendingClick()
     m_selectedLabelIndex = m_renderer->m_selectedLabelIndex;
     m_selectedCustomItemIndex = m_renderer->m_selectedCustomItemIndex;
 
+    // Invalidate query position to indicate the query has been handled, unless another
+    // point has been queried.
+    if (m_renderer->cachedClickQuery() == m_scene->selectionQueryPosition())
+        m_scene->setSelectionQueryPosition(Q3DScene::invalidSelectionPoint());
+
+    m_renderer->clearClickQueryResolved();
+
     emit elementSelected(m_clickedType);
 }
 
 void Abstract3DController::handlePendingGraphPositionQuery()
 {
     m_queriedGraphPosition = m_renderer->queriedGraphPosition();
+
+    // Invalidate query position to indicate the query has been handled, unless another
+    // point has been queried.
+    if (m_renderer->cachedGraphPositionQuery() == m_scene->graphPositionQuery())
+        m_scene->setGraphPositionQuery(Q3DScene::invalidSelectionPoint());
+
+    m_renderer->clearGraphPositionQueryResolved();
+
     emit queriedGraphPositionChanged(m_queriedGraphPosition);
 }