Re: pathfinding refueling

[Peter Garrone <pgarrone at acay dot com dot au>]

On Sat, Dec 20, 2003 at 11:48:59PM +0100, Hans Ronne wrote:
> >> I have spent hours on all these emails. I would rather just code up my
> >> approach now thanks. Fat chance.
> >
> >So then code it up. I already told you that I am not stopping you
> >(I cannot stop you). Just don't expect me to check it in; I think
> >your proposed solution is a bit narrow-minded in some cases.
> 
> I think it is perhaps time to conclude this discussion and move on.

There are many constructive comments in this thread, particularly from
Hans. This is very helpful. It is tricky territory though.

> The new
> path-finding code is a significant improvement, and I would very much like
> it to be included in the 7.5 release. However, there are three problems
> that must be solved first:
> 
> 1. Sync errors (unless the cache is disabled).
> 2. Ferry problems.
> 3. Resupply problems.
> 
> If Peter can fix these problems, this will be a major contribution which is
> certainly welcome. Maybe it doesn't address all possible scenarios, but we
> can't let perfection be the enemy of good. Further improvements to the code
> can always be made later, if necessary.

I am trying to address all these. I think we should accept that it will
be a major development though. I should have some time over the next few
weeks.

> 
> As for supporting more than one fuel, which is what much of the discussion
> has been about, it is easy to do so if the path is recomputed when the unit
> reaches a resupply point. And we already agreed that frequent
> recalculations of the path is a good idea. All it would take is to check
> what material is currently limiting the range, and use it as "fuel" in the
> new path calculation. This would allow more than one material type to be
> considered as fuel, and at the same time avoid the computational problems
> that several fuel types would cause in any given path calculation.

Perhaps dynamically changing the fuel type is the way but I cant see it right
now. For now I plan to implement a multiple refuel of all material types
that could constrain movement at resupply points, and if it is out of any
such material in that it could not top up the unit, disallow that resupply point, both in the path-finding,
and in the actual movement. But only the fuel type giving the minimal
range will be actually tracked in the path-finding node state.
It should be unnecessary to change fuel types in this manner because if
the unit cannot be supplied with sufficient quantities of all fuel
types, then both the pathfind will fail or the actual move task will
fail.
I do not think i was planning to do this before this thread, so this has
developed anyhow.

There is no way to tell in the pathfind that some other material than
the tracked fuel is in short supply, because only the main fuel is
tracked.

> 
> I would therefore encourage Peter to go ahead with his scheme but include
> dynamic recalculations of the path as often as is practical, and also make
> the choice of which material type should be considered as "fuel" dynamic,
> depending on the unit's supplies.
> 
> Hans
> 

Thanks for your contribution. But I would urge anyone who has any input
to continue to provide it. If an algorithm is suggested, and I cannot
think of a reason good why it wouldnt work, then I would use it.
It is actually quite helpful to knock suggested algorithms over.
 Peter