Creating polygon using QSGGeometry

[literA2]

Hi,

I'm a beginner in QML, please bear with me. :) This is my first attempt to use scene graph instead of using QPainter.

After doing some research on the internet, I can't find an example in creating a polygon and a rounded rectangle in scene graph using QSGGeometry.
I tried using vertexDataAsPoint2D in creating a polygon however I can't connect the vertices.
And you please include also how to add text on nodes.
Can you please provide a sample that I can follow.

Thanks.