[Haskell-cafe] octree implementation - followup to "How to model outer space for a MUD"

[Michael Litchard]

Perfect, thanks to you both.

On Thu, Aug 20, 2015 at 1:50 PM, Michael Steele <mikesteele81 at gmail.com>
wrote:

> Michael,
>
> In case your interested in another example, there's also a quadtree in the
> "gloss-algorithms" [1] package.
>
> [1]: http://hackage.haskell.org/package/gloss-algorithms
>
> On Thu, Aug 20, 2015 at 1:41 PM, Tikhon Jelvis <tikhon at jelv.is> wrote:
>
>> Are you already familiar with lenses? From a glance at the code you
>> linked, it will be hard to understand what's going on unless you are.
>>
>> Personally, my advice is to implement a simple, limited quadtree
>> yourself. The first part of "Functional Programming with QuadTrees"[1] is
>> basically a tutorial on quadtrees with code in Miranda—eminently readable
>> for Haskellers. That's where I would start: write up the code from their
>> examples in Haskell, play around with it and add an extra function or two
>> to understand what's going on.
>>
>> Once you have an intuition for the underlying ideas, you can expand it to
>> octtrees and more complex operations.
>>
>> [1]:
>> http://conal.net/papers/warren-burton/Functional%20Programming%20and%20Quadtrees.pdf
>>
>> On Thu, Aug 20, 2015 at 1:30 PM, Michael Litchard <michael at schmong.org>
>> wrote:
>>
>>> It looks like Octree is what I want if I can solve a particular problem.
>>> First let me articulate what I am looking for.
>>>
>>> (1) Objects in 3-d space with no spatial extent. Collision is determined
>>> by two objects occupying the same point.'
>>>
>>> (2) Efficient insert-delete-update
>>>
>>> #2 seems to be the problem. I found this library, thankfully. I believe
>>> it's exactly what I am looking for, but for quadtrees.
>>>
>>> https://github.com/AshleyMoni/QuadTree
>>>
>>> I'm a little overwhelmed as this is a new data structure for me. I
>>> believe if I can grok what is going on in this library, I can take these
>>> ideas and extend them to the octree. I'm referring specifically to this
>>> module
>>>
>>>
>>> https://github.com/AshleyMoni/QuadTree/blob/master/Data/QuadTree/Internal.hs
>>>
>>> And these functions
>>>
>>> setLocation :: Eq a => Location -> a -> QuadTree a -> QuadTree a
>>> setLocation = set . atLocation
>>>
>>> atLocation (Having difficulty cutting and pasting this to mail.)
>>>
>>> I'd like to be able to visualize how the tree is being compressed, it
>>> may help to be able to see what happens to the tree when it's not
>>> compressed.
>>>
>>> Does anyone have a pointer or advice in how to break this library down
>>> in parts to help me grok, in a way that will help me extend to octree?
>>>
>>>
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>>>
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>>>
>>>
>>
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>>
>
>
> --
> -- Michael Steele
>
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