# Boost :

Subject: Re: [boost] GGL Questions
From: Bruno Lalande (bruno.lalande_at_[hidden])
Date: 2009-11-12 18:52:03

Just realized that fixing the subject name might have messed things up
in some email clients, so I put the original email below...

Bruno

On Thu, Nov 12, 2009 at 4:16 PM, Peter Schregle
<p.schregle_at_[hidden]> wrote:
> We are thinking about replacing our geometric algorithms with the ones from
> GGL.
>
> We would want to somehow adapt our own geometric primitives so that GGL can
> work with them, and with points, line segments and polygons this works
> rather nicely.
>
> However, we also have a few other concepts, where we have not found a simple
> way to adapt them to GGL.
>
> 1) Line
> We consider a line being an infinite line in the mathematical sense, i.e. it
> does not have endpoints but extends into infinity on both sides. We want to
> be able to calculate the distance between such a line and a point, or the
> point of intersection ot two lines if it exists.
>
> 2) Ray
> We consider a ray being a line with one endpoint or origin, and extending
> into infinity. Here also we want to be able to calculate the distance
> between a ray and a point, or between two rays, or points of intersections
> etc.
>
> 3) Direction
> In order to implement a line and a ray as descibed above, we have introduced
> the concept of direction (which is basically the same as a direction unit
> vector, or an equivalent angle). Is there a concept like this in GGL? How
> could we calculate the angle of a line segment in GGL?
>
> Best regards
> Peter
>
> PS: By the way: I find the acronym GGL unfortunate. For me it feels a bit
> awkward, and I was typing it wrong all the time while preparing this text.
> Everytime I use it I'm forced to think hard about what it means, in order to
> get it right. I would prefer a more descriptive name like geometry or
> geolib, or something else that can be memorized better.
>
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