[Tracking Upstream Issue amethyst/amethyst#2517]: Legion: Final Tracker

[ezpuzz]

This is a tracking issue created by Radium.io, please see original at amethyst#2517

[ezpuzz]

leaving my personal notes here about status of port...

• pong examples are blocked on amethyst_ui port
• amethyst_ui port is large and difficult (lots of systems to port)

[ezpuzz]

amethyst_ui

put some work in progress on the https://github.com/radium-io/amethyst/tree/amethyst-ui branch

some thoughts:

was able to convert ui transforms system to legion but unknown if it works properly.
there is tight coupling between the different ui mods.

the new amethyst/legion#165 proc macros for systems may make this nicer to look at, not sure if anyone else is doing that

learning what some of the changes needed are I think there is a more holistic approach to the legion transtion that is horizontal across the amethyst codebase... amethyst_derive. As a bonus this will make existing amethyst projects easier to port to legion.

going to look in to that next

[ezpuzz]

amethyst_derive transition attempt 1 consists of nuking the SystemDesc derive entirely and seeing how many fires it causes.

got sidetracked by improving CI coverage to really see how far legion_v2 is from green light. that was merged, which is awesome!

attempting to get sprites_ordered functional because that is a simple core example with core systems. thinking of adding HiddenPropagate to it to test hierarchical functions.