[Freeciv-Dev] Re: the directional system

[Raimar Falke <hawk@xxxxxxxxxxxxxxxxxxxxxxx>]

On Sun, Sep 09, 2001 at 03:39:51AM -0400, Jason Dorje Short wrote:
> Raimar Falke wrote:
> 
> > I still don't understand it. DIR_DX2 is only used in one method. Why
> > not just convert this and be fine (at least as an immediate step) with
> > one system. Why to switch all over to the DIR_DX2 system? Why is the
> > DIR_DX2 inferior to the DIR_DX system (not the naming but the
> > ordering)?
> 
> The problem is the DIR_DX2 "rotational" system is superior to the DIR_DX
> "vertical" system: 

> easier to code with

This should be a non issue if you use "enum direction8" and iterate
macros.

> more efficient for most algorithms

In almost all algorithms you go over ALL neighbor positions. About
which algorithms do we speak here?

>, and all-around more understandable

It is just the ordering which differs. And with "enum direction8" the
programmer shouldn't care about it

> (For a more detailed explanation ask Ross.)

Ross?

> My plan was/is to wait until we can convert all code at once.  Thus, one
> of the first steps is to get rid of the DIR_DX2 arrays entirely so that
> there's just one system.

This is ok.

> In summary, we all want to use the "rotational" system but disagree as
> to how to best do the conversion.

And I still don't understand why you two find the "rotational" better.

> The DIR_DX2 system, by the way, was recently introduced to FreeCiv by
> (IIRC) Thue.  But, he didn't get very far in converting FreeCiv over to
> its use: it's only used in one place.

Exactly. And even at this one place it provides no advantage. Thue?

        Raimar

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