Refactor prefetching tiles

Current implementation uses same QGeoCameraTiles object
to calculate visible tiles and tiles which should be
prefetched. This is semi optimal since frustum intersection
algorithm uses bunch of different parameters.

Simplify the logic and use separate objects, this way
values in both cases are cached and calculation is done when required.
This is important since prefetchData can be called
anytime from map's API.

Remove textured tiles from scene when clearCache called,
this will force redownload of all the tiles.

Add new unit test qgeotiledmap and move prefetch test
due to refactoring.

Change-Id: I6a906df405f212436cdd35ac76f95b559e6b7aae
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/location/maps/qgeotiledmap_p_p.h b/src/location/maps/qgeotiledmap_p_p.h
index 2e93a006..15442bd1 100644
--- a/src/location/maps/qgeotiledmap_p_p.h
+++ b/src/location/maps/qgeotiledmap_p_p.h
@@ -93,9 +93,12 @@ private:
 
 private:
     QAbstractGeoTileCache *m_cache;
-    QGeoCameraTiles *m_cameraTiles;
+    QGeoCameraTiles *m_visibleTiles;
+    QGeoCameraTiles *m_prefetchTiles;
     QGeoMapScene *m_mapScene;
     QGeoTileRequestManager *m_tileRequests;
+    int m_maxZoomLevel;
+    QGeoTiledMap::PrefetchStyle m_prefetchStyle;
     Q_DISABLE_COPY(QGeoTiledMapPrivate)
 };