Fix rendering issue with material changes from opaque <-> alpha

When I introduced the invalidation of z ranges, I forgot that we need
to rebuild render lists when nodes move from opaque to alpha batches
or vice versa as that sorting happens in buildRenderLists(). To remedy
this, make Batch::isMaterialCompatible report blending changes
separately and trigger a full rebuild in this case.

Task-number: QTBUG-37422
Change-Id: I020813cb531ed58353f8340fcad58dec8d7856dd
Reviewed-by: Michael Brasser <michael.brasser@live.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h b/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
index 7c06de774a..3972a98d8b 100644
--- a/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
+++ b/src/quick/scenegraph/coreapi/qsgbatchrenderer_p.h
@@ -231,11 +231,18 @@ struct DrawSet
     int indexCount;
 };
 
+enum BatchCompatibility
+{
+    BatchBreaksOnBlending,
+    BatchBreaksOnCompare,
+    BatchIsCompatible
+};
+
 struct Batch
 {
     Batch() : drawSets(1) {}
     bool geometryWasChanged(QSGGeometryNode *gn);
-    bool isMaterialCompatible(Element *e) const;
+    BatchCompatibility isMaterialCompatible(Element *e) const;
     void invalidate();
     void cleanupRemovedElements();