Mark layers in the SW rasterizer as opaque if possible

If the content of a layer completely covers every pixel of
it, mark that layer as opaque so that we can avoid alpha
blending where possible.

Change-Id: Ia0be4e7a96ecddd31a26f353509de976bcc9e397
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
Reviewed-by: Volker Krause <volker.krause@kdab.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/quick/scenegraph/adaptations/software/qsgabstractsoftwarerenderer_p.h b/src/quick/scenegraph/adaptations/software/qsgabstractsoftwarerenderer_p.h
index 04a17ea377..c68a933384 100644
--- a/src/quick/scenegraph/adaptations/software/qsgabstractsoftwarerenderer_p.h
+++ b/src/quick/scenegraph/adaptations/software/qsgabstractsoftwarerenderer_p.h
@@ -86,6 +86,8 @@ protected:
     void setBackgroundSize(const QSize &size);
     QColor backgroundColor();
     QSize backgroundSize();
+    // only known after calling optimizeRenderList()
+    bool isOpaque() const { return m_isOpaque; }
 
 private:
     void nodeAdded(QSGNode *node);
@@ -102,6 +104,7 @@ private:
 
     QRegion m_dirtyRegion;
     QRegion m_obscuredRegion;
+    bool m_isOpaque;
 
     QSGSoftwareRenderableNodeUpdater *m_nodeUpdater;
 };