Display the cross-section when using clipping planes

Currently, it is possible set clipping-planes on Giro3D entities. However, the cross-section itself is not visible:

Expected result (the cross section is visible in dark red):

Implementation

To display the actual cross-section, we can use a technique that makes use of the stencil buffer, as seen in this three.js example.

For every object that intersects the clipping plane, we must create 2 additional clones with special materials setup for stencil buffer operations.

There must also be a plane mesh that is located on the clipping plane, and the material of this mesh will display the cross-section.