Speed grouping

[Mailaender]

All units stick together as they don't move faster than the slowest unit in the selected group. Original RA95.exe shortcut was F. http://ra.afraid.org/html/ra/hotkeys.html

The original implementation had an exploitable bug as it did speed up slow moving units when grouped together with fast ones. http://ra.afraid.org/html/extra/cheats.html Obviously this should be avoided.

Wished at:

• Wishlist for classic mods #2740 (comment)
• http://openra.res0l.net/news/release-20130915/#comment-1052353859

[pchote]

This would be helpful for the AI too.

Most of the plumbing already exists (see the ActorGroupProxy trait and CreateGroup order) - it just needs some simple code to calculate the group speed and pass it on to the IMove trait on each actor.

[phrohdoh]

It feels that if unit A B and C are escorting unit D, but D is the fastest... unit D should slow down to stay with the units guarding it.
This is especially present and would be useful for an MCV. It is faster than most ground units and will speed ahead of those trying to defend it.

[Mailaender]

Note to myself: glue a new GroupSpeed and OpenRA.Mods.RA/Player/ActorGroupProxy.cs together.

[Mailaender]

See also #3866 where this seems to fail. Need to make sure it works well with the AI as we want to win some performance back here.

[Mailaender]

If we want to expand on that, we might want to go with a Age of Empires like formations system which automatically sorts the units with most hit points up front. http://www.gamasutra.com/view/feature/131844/postmortem_ensemble_studios_age_.php?page=2

[whi7ed3vil]

Referencing #10495, The question is raised as to whether formations should be a default style of movement, notwithstanding formations that would remain so during motion. It is somewhat sensible to maintain an ordered formation with simple selection in many cases rather than bunching into a single point. Perhaps a first-order, second-order system would allow a user to move units while remaining in formation for the first click, but break formation on the second order?

[xan2622]

I have asked 0 A.D. developers, their code to manage formations is contained in these files:

https://github.com/0ad/0ad/blob/master/binaries/data/mods/public/simulation/components/Formation.js

https://github.com/0ad/0ad/blob/master/binaries/data/mods/public/simulation/components/UnitAI.js

https://github.com/0ad/0ad/blob/9eb6d217da92ef5f8f25a2138b5a77d1a0e13d0e/source/simulation2/components/CCmpUnitMotion.cpp

Dunno if that helps... (I know it's not C# but maybe it could inspire you to find the way to add RA95 formations).

Btw, I wonder how (visually) you'd like to implement the different formations?
Something like that? (dots on another bar, or on the command bar maybe?)

[pchote]

In the C&C games formations duplicate the layout of the units at the start instead of having fixed layouts like 0 A.D.

[Mailaender]

I suggest a new ticket for actual gen2/gen3 formations. This is about the original speed grouping.

[pchote]

This ticket is called "formations" and links to a web site that explicitly describes

Units in formation will try to maintain their order as you had them when you made the formation

It might be more appropriate to create a new ticket for speed grouping 😄

[jg00dman]

I think the value of the original implementation was significant. It was possible to shield rocketeers behind tanks for example.