Multiplayer AR shooter proof of concept

In fact, this is prehistory of "Demons Hunter" project. A lot of time ago, a long before the ARKit2 and ARCore 1.3 with their features to share the places of real world between devices (cloud anchors), I tried to develop the AR multiplayer shooter proof of concept. It was successful...
Problem was that every device has its own understanding where the point (0,0,0) in real world and which orientation the world "forward" has. I tried the several ways to synchronize the coordinates of world for several devices, including the using markers. Basic idea is to fix at some moment all devices at the same position and same rotation and remember this point and orientation. Worked enough good. Later on desire of one of my clients I used PlaceNote SDK which provided the presistance service for ARKit. Obsolete in fact.

So for both Placenote version and "choose the common center of the world" the results was enough good: devices knows the position and rotation of each other so see the weapons and beams of shoots of each other at proper places. They also can see the enemies at the same place relatively to real world so fire to same enemy all together.

Whith latest version ARKit/ARCore the development of such games was much easier. I was thinking to develop full scale shooter based on this proof of concept, but had no enough time as busy on paid jobs for clients and did not found the investors.