Add a property to enable vertical mirroring in QQuickFramebufferObject

[ChangeLog] Added a mirrorVertically property to QQuickFramebufferObject.

Task-number: QTBUG-41073
Change-Id: Ib69cbfe7b2f6ae42913d857460431195ff92e53a
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/quick/items/qquickframebufferobject.cpp b/src/quick/items/qquickframebufferobject.cpp
index c3e5b97baf..18e786fea4 100644
--- a/src/quick/items/qquickframebufferobject.cpp
+++ b/src/quick/items/qquickframebufferobject.cpp
@@ -47,11 +47,13 @@ class QQuickFramebufferObjectPrivate : public QQuickItemPrivate
 public:
     QQuickFramebufferObjectPrivate()
         : followsItemSize(true)
+        , mirrorVertically(false)
         , node(0)
     {
     }
 
     bool followsItemSize;
+    bool mirrorVertically;
     mutable QSGFramebufferObjectNode *node;
 };
 
@@ -138,6 +140,34 @@ bool QQuickFramebufferObject::textureFollowsItemSize() const
 }
 
 /*!
+ * \property QQuickFramebufferObject::mirrorVertically
+ *
+ * This property controls if the size of the FBO's contents should be mirrored
+ * vertically when drawing. This allows easy integration of third-party
+ * rendering code that does not follow the standard expectations.
+ *
+ * The default value is \c {false}.
+ *
+ * \since 5.6
+ */
+
+void QQuickFramebufferObject::setMirrorVertically(bool enable)
+{
+    Q_D(QQuickFramebufferObject);
+    if (d->mirrorVertically == enable)
+        return;
+    d->mirrorVertically = enable;
+    emit mirrorVerticallyChanged(d->mirrorVertically);
+    update();
+}
+
+bool QQuickFramebufferObject::mirrorVertically() const
+{
+    Q_D(const QQuickFramebufferObject);
+    return d->mirrorVertically;
+}
+
+/*!
  * \internal
  */
 void QQuickFramebufferObject::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
@@ -290,6 +320,7 @@ QSGNode *QQuickFramebufferObject::updatePaintNode(QSGNode *node, UpdatePaintNode
                                                     QQuickWindow::TextureHasAlphaChannel));
     }
 
+    n->setTextureCoordinatesTransform(d->mirrorVertically ? QSGSimpleTextureNode::MirrorVertically : QSGSimpleTextureNode::NoTransform);
     n->setFiltering(d->smooth ? QSGTexture::Linear : QSGTexture::Nearest);
     n->setRect(0, 0, width(), height());