Fix crash in Map{Polyline,Polygon,Route}ObjectQsg

When these objects get added to a map but aren't immediately visible
(meaning are outside the visible region entirely), their respective
QSGNodes will be marked as blocked.
However, this isn't handled gracefully in qsgbatchrenderer.
Renderer::nodeWasAdded discards nodes that are blocked.
Meaning that when they will become unblocked, the node will
result in being unallocated.

This patch makes sure that a node is not instantiated at all
if it would result in a blocked node.

Change-Id: I8e174ba1d317e1d0c4006d993ec558bdad8a5b39
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

2 files changed, 4 insertions, 0 deletions

diff --git a/src/location/labs/qsg/qmappolygonobjectqsg.cpp b/src/location/labs/qsg/qmappolygonobjectqsg.cpp
index b9602a3a..239df177 100644
--- a/src/location/labs/qsg/qmappolygonobjectqsg.cpp
+++ b/src/location/labs/qsg/qmappolygonobjectqsg.cpp
@@ -85,6 +85,8 @@ QSGNode *QMapPolygonObjectPrivateQSG::updateMapObjectNode(QSGNode *oldNode,
 
     bool created = false;
     if (!node) {
+        if (!m_geometry.size() && !m_borderGeometry.size())
+            return nullptr;
         node = new MapPolygonNode();
         *visibleNode = static_cast<VisibleNode *>(node);
         created = true;
diff --git a/src/location/labs/qsg/qmappolylineobjectqsg.cpp b/src/location/labs/qsg/qmappolylineobjectqsg.cpp
index 6b782c77..f4a1a288 100644
--- a/src/location/labs/qsg/qmappolylineobjectqsg.cpp
+++ b/src/location/labs/qsg/qmappolylineobjectqsg.cpp
@@ -107,6 +107,8 @@ QSGNode *QMapPolylineObjectPrivateQSG::updateMapObjectNode(QSGNode *oldNode,
 
     bool created = false;
     if (!node) {
+        if (!m_geometry.size()) // condition to block the subtree
+            return nullptr;
         node = new MapPolylineNode();
         *visibleNode = static_cast<VisibleNode *>(node);
         created = true;