monochrome shape nodes with QSGVertexColorMaterial

[uwerat]

Using QSGVertexColorMaterial - instead of QSGFlatColorMaterial - is a waste of memory as the color information is added to each vertex. However using the same material for all shapes and boxes allows better batching and therefore a better render performance can be expected.

So it would be good to have a a mode in QskShapeNode, that is using QSGVertexColorMaterial .