Andreas/evennia
1
0
Fork 0
mirror of https://github.com/evennia/evennia.git synced 2026-03-18 05:46:31 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions
evennia/docs/0.x/Coordinates.html
Griatch fe3ad71ae6 Add 0.x legacy docs
2023-12-20 19:10:09 +01:00

456 lines
No EOL
42 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="generator" content="Docutils 0.17.1: http://docutils.sourceforge.net/" />
<title>Coordinates &#8212; Evennia 0.9.5 documentation</title>
<link rel="stylesheet" href="_static/nature.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<script id="documentation_options" data-url_root="./" src="_static/documentation_options.js"></script>
<script src="_static/jquery.js"></script>
<script src="_static/underscore.js"></script>
<script src="_static/doctools.js"></script>
<script src="_static/language_data.js"></script>
<script async="async" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/latest.js?config=TeX-AMS-MML_HTMLorMML"></script>
<script type="text/x-mathjax-config">MathJax.Hub.Config({"tex2jax": {"processClass": "tex2jax_process|mathjax_process|math|output_area"}})</script>
<link rel="shortcut icon" href="_static/favicon.ico"/>
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
</head><body>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="nav-item nav-item-0"><a href="index.html">Evennia 0.9.5</a> &#187;</li>
<li class="nav-item nav-item-this"><a href="">Coordinates</a></li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<section class="tex2jax_ignore mathjax_ignore" id="coordinates">
<h1>Coordinates<a class="headerlink" href="#coordinates" title="Permalink to this headline"></a></h1>
</section>
<section class="tex2jax_ignore mathjax_ignore" id="adding-room-coordinates-in-your-game">
<h1>Adding room coordinates in your game<a class="headerlink" href="#adding-room-coordinates-in-your-game" title="Permalink to this headline"></a></h1>
<p>This tutorial is moderately difficult in content. You might want to be familiar and at ease with
some Python concepts (like properties) and possibly Django concepts (like queries), although this
tutorial will try to walk you through the process and give enough explanations each time. If you
don’t feel very confident with math, don’t hesitate to pause, go to the example section, which shows
a tiny map, and try to walk around the code or read the explanation.</p>
<p>Evennia doesn’t have a coordinate system by default. Rooms and other objects are linked by location
and content:</p>
<ul class="simple">
<li><p>An object can be in a location, that is, another object. Like an exit in a room.</p></li>
<li><p>An object can access its content. A room can see what objects uses it as location (that would
include exits, rooms, characters and so on).</p></li>
</ul>
<p>This system allows for a lot of flexibility and, fortunately, can be extended by other systems.
Here, I offer you a way to add coordinates to every room in a way most compliant with Evennia
design. This will also show you how to use coordinates, find rooms around a given point for
instance.</p>
<section id="coordinates-as-tags">
<h2>Coordinates as tags<a class="headerlink" href="#coordinates-as-tags" title="Permalink to this headline"></a></h2>
<p>The first concept might be the most surprising at first glance: we will create coordinates as
<a class="reference internal" href="Tags.html"><span class="doc std std-doc">tags</span></a>.</p>
<blockquote>
<div><p>Why not attributes, wouldn’t that be easier?</p>
</div></blockquote>
<p>It would. We could just do something like <code class="docutils literal notranslate"><span class="pre">room.db.x</span> <span class="pre">=</span> <span class="pre">3</span></code>. The advantage of using tags is that it
will be easy and effective to search. Although this might not seem like a huge advantage right now,
with a database of thousands of rooms, it might make a difference, particularly if you have a lot of
things based on coordinates.</p>
<p>Rather than giving you a step-by-step process, I’ll show you the code. Notice that we use
properties to easily access and update coordinates. This is a Pythonic approach. Here’s our first
<code class="docutils literal notranslate"><span class="pre">Room</span></code> class, that you can modify in <code class="docutils literal notranslate"><span class="pre">typeclasses/rooms.py</span></code>:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># in typeclasses/rooms.py</span>
<span class="kn">from</span> <span class="nn">evennia</span> <span class="kn">import</span> <span class="n">DefaultRoom</span>
<span class="k">class</span> <span class="nc">Room</span><span class="p">(</span><span class="n">DefaultRoom</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Rooms are like any Object, except their location is None</span>
<span class="sd"> (which is default). They also use basetype_setup() to</span>
<span class="sd"> add locks so they cannot be puppeted or picked up.</span>
<span class="sd"> (to change that, use at_object_creation instead)</span>
<span class="sd"> See examples/object.py for a list of</span>
<span class="sd"> properties and methods available on all Objects.</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="nd">@property</span>
<span class="k">def</span> <span class="nf">x</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Return the X coordinate or None.&quot;&quot;&quot;</span>
<span class="n">x</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
<span class="k">return</span> <span class="nb">int</span><span class="p">(</span><span class="n">x</span><span class="p">)</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="nb">str</span><span class="p">)</span> <span class="k">else</span> <span class="kc">None</span>
<span class="nd">@x</span><span class="o">.</span><span class="n">setter</span>
<span class="k">def</span> <span class="nf">x</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Change the X coordinate.&quot;&quot;&quot;</span>
<span class="n">old</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">old</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">old</span><span class="p">,</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">x</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">x</span><span class="p">),</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
<span class="nd">@property</span>
<span class="k">def</span> <span class="nf">y</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Return the Y coordinate or None.&quot;&quot;&quot;</span>
<span class="n">y</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordy&quot;</span><span class="p">)</span>
<span class="k">return</span> <span class="nb">int</span><span class="p">(</span><span class="n">y</span><span class="p">)</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">y</span><span class="p">,</span> <span class="nb">str</span><span class="p">)</span> <span class="k">else</span> <span class="kc">None</span>
<span class="nd">@y</span><span class="o">.</span><span class="n">setter</span>
<span class="k">def</span> <span class="nf">y</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">y</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Change the Y coordinate.&quot;&quot;&quot;</span>
<span class="n">old</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordy&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">old</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">old</span><span class="p">,</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordy&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">y</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">y</span><span class="p">),</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordy&quot;</span><span class="p">)</span>
<span class="nd">@property</span>
<span class="k">def</span> <span class="nf">z</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Return the Z coordinate or None.&quot;&quot;&quot;</span>
<span class="n">z</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordz&quot;</span><span class="p">)</span>
<span class="k">return</span> <span class="nb">int</span><span class="p">(</span><span class="n">z</span><span class="p">)</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">z</span><span class="p">,</span> <span class="nb">str</span><span class="p">)</span> <span class="k">else</span> <span class="kc">None</span>
<span class="nd">@z</span><span class="o">.</span><span class="n">setter</span>
<span class="k">def</span> <span class="nf">z</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">z</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Change the Z coordinate.&quot;&quot;&quot;</span>
<span class="n">old</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordz&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">old</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">old</span><span class="p">,</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordz&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">z</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">z</span><span class="p">),</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordz&quot;</span><span class="p">)</span>
</pre></div>
</div>
<p>If you aren’t familiar with the concept of properties in Python, I encourage you to read a good
tutorial on the subject. <a class="reference external" href="https://www.programiz.com/python-programming/property">This article on Python properties</a>
is well-explained and should help you understand the idea.</p>
<p>Let’s look at our properties for <code class="docutils literal notranslate"><span class="pre">x</span></code>. First of all is the read property.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span> <span class="nd">@property</span>
<span class="k">def</span> <span class="nf">x</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Return the X coordinate or None.&quot;&quot;&quot;</span>
<span class="n">x</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
<span class="k">return</span> <span class="nb">int</span><span class="p">(</span><span class="n">x</span><span class="p">)</span> <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="nb">str</span><span class="p">)</span> <span class="k">else</span> <span class="kc">None</span>
</pre></div>
</div>
<p>What it does is pretty simple:</p>
<ol class="simple">
<li><p>It gets the tag of category <code class="docutils literal notranslate"><span class="pre">&quot;coordx&quot;</span></code>. It’s the tag category where we store our X coordinate.
The <code class="docutils literal notranslate"><span class="pre">tags.get</span></code> method will return <code class="docutils literal notranslate"><span class="pre">None</span></code> if the tag can’t be found.</p></li>
<li><p>We convert the value to an integer, if it’s a <code class="docutils literal notranslate"><span class="pre">str</span></code>. Remember that tags can only contain <code class="docutils literal notranslate"><span class="pre">str</span></code>,
so we’ll need to convert it.</p></li>
</ol>
<blockquote>
<div><p>I thought tags couldn’t contain values?</p>
</div></blockquote>
<p>Well, technically, they can’t: they’re either here or not. But using tag categories, as we have
done, we get a tag, knowing only its category. That’s the basic approach to coordinates in this
tutorial.</p>
<p>Now, let’s look at the method that will be called when we wish to set <code class="docutils literal notranslate"><span class="pre">x</span></code> in our room:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span> <span class="nd">@x</span><span class="o">.</span><span class="n">setter</span>
<span class="k">def</span> <span class="nf">x</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;Change the X coordinate.&quot;&quot;&quot;</span>
<span class="n">old</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">old</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">old</span><span class="p">,</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">x</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">x</span><span class="p">),</span> <span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span>
</pre></div>
</div>
<ol class="simple">
<li><p>First, we remove the old X coordinate, if it exists. Otherwise, we’d end up with two tags in our
room with “coordx” as their category, which wouldn’t do at all.</p></li>
<li><p>Then we add the new tag, giving it the proper category.</p></li>
</ol>
<blockquote>
<div><p>Now what?</p>
</div></blockquote>
<p>If you add this code and reload your game, once you’re logged in with a character in a room as its
location, you can play around:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="nd">@py</span> <span class="n">here</span><span class="o">.</span><span class="n">x</span>
<span class="nd">@py</span> <span class="n">here</span><span class="o">.</span><span class="n">x</span> <span class="o">=</span> <span class="mi">0</span>
<span class="nd">@py</span> <span class="n">here</span><span class="o">.</span><span class="n">y</span> <span class="o">=</span> <span class="mi">3</span>
<span class="nd">@py</span> <span class="n">here</span><span class="o">.</span><span class="n">z</span> <span class="o">=</span> <span class="o">-</span><span class="mi">2</span>
<span class="nd">@py</span> <span class="n">here</span><span class="o">.</span><span class="n">z</span> <span class="o">=</span> <span class="kc">None</span>
</pre></div>
</div>
<p>The code might not be that easy to read, but you have to admit it’s fairly easy to use.</p>
</section>
<section id="some-additional-searches">
<h2>Some additional searches<a class="headerlink" href="#some-additional-searches" title="Permalink to this headline"></a></h2>
<p>Having coordinates is useful for several reasons:</p>
<ol class="simple">
<li><p>It can help in shaping a truly logical world, in its geography, at least.</p></li>
<li><p>It can allow to look for specific rooms at given coordinates.</p></li>
<li><p>It can be good in order to quickly find the rooms around a location.</p></li>
<li><p>It can even be great in path-finding (finding the shortest path between two rooms).</p></li>
</ol>
<p>So far, our coordinate system can help with 1., but not much else. Here are some methods that we
could add to the <code class="docutils literal notranslate"><span class="pre">Room</span></code> typeclass. These methods will just be search methods. Notice that they are
class methods, since we want to get rooms.</p>
<section id="finding-one-room">
<h3>Finding one room<a class="headerlink" href="#finding-one-room" title="Permalink to this headline"></a></h3>
<p>First, a simple one: how to find a room at a given coordinate? Say, what is the room at X=0, Y=0,
Z=0?</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Room</span><span class="p">(</span><span class="n">DefaultRoom</span><span class="p">):</span>
<span class="c1"># ...</span>
<span class="nd">@classmethod</span>
<span class="k">def</span> <span class="nf">get_room_at</span><span class="p">(</span><span class="bp">cls</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">,</span> <span class="n">z</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Return the room at the given location or None if not found.</span>
<span class="sd"> Args:</span>
<span class="sd"> x (int): the X coord.</span>
<span class="sd"> y (int): the Y coord.</span>
<span class="sd"> z (int): the Z coord.</span>
<span class="sd"> Return:</span>
<span class="sd"> The room at this location (Room) or None if not found.</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="n">rooms</span> <span class="o">=</span> <span class="bp">cls</span><span class="o">.</span><span class="n">objects</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span>
<span class="n">db_tags__db_key</span><span class="o">=</span><span class="nb">str</span><span class="p">(</span><span class="n">x</span><span class="p">),</span> <span class="n">db_tags__db_category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span>
<span class="n">db_tags__db_key</span><span class="o">=</span><span class="nb">str</span><span class="p">(</span><span class="n">y</span><span class="p">),</span> <span class="n">db_tags__db_category</span><span class="o">=</span><span class="s2">&quot;coordy&quot;</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span>
<span class="n">db_tags__db_key</span><span class="o">=</span><span class="nb">str</span><span class="p">(</span><span class="n">z</span><span class="p">),</span> <span class="n">db_tags__db_category</span><span class="o">=</span><span class="s2">&quot;coordz&quot;</span><span class="p">)</span>
<span class="k">if</span> <span class="n">rooms</span><span class="p">:</span>
<span class="k">return</span> <span class="n">rooms</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span>
<span class="k">return</span> <span class="kc">None</span>
</pre></div>
</div>
<p>This solution includes a bit of <a class="reference external" href="https://docs.djangoproject.com/en/1.11/topics/db/queries/">Django
queries</a>.
Basically, what we do is reach for the object manager and search for objects with the matching tags.
Again, don’t spend too much time worrying about the mechanism, the method is quite easy to use:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">Room</span><span class="o">.</span><span class="n">get_room_at</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="o">-</span><span class="mi">3</span><span class="p">)</span>
</pre></div>
</div>
<p>Notice that this is a class method: you will call it from <code class="docutils literal notranslate"><span class="pre">Room</span></code> (the class), not an instance.
Though you still can:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>@py here.get_room_at(3, 8, 0)
</pre></div>
</div>
</section>
<section id="finding-several-rooms">
<h3>Finding several rooms<a class="headerlink" href="#finding-several-rooms" title="Permalink to this headline"></a></h3>
<p>Here’s another useful method that allows us to look for rooms around a given coordinate. This is
more advanced search and doing some calculation, beware! Look at the following section if you’re
lost.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">math</span> <span class="kn">import</span> <span class="n">sqrt</span>
<span class="k">class</span> <span class="nc">Room</span><span class="p">(</span><span class="n">DefaultRoom</span><span class="p">):</span>
<span class="c1"># ...</span>
<span class="nd">@classmethod</span>
<span class="k">def</span> <span class="nf">get_rooms_around</span><span class="p">(</span><span class="bp">cls</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">,</span> <span class="n">z</span><span class="p">,</span> <span class="n">distance</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> Return the list of rooms around the given coordinates.</span>
<span class="sd"> This method returns a list of tuples (distance, room) that</span>
<span class="sd"> can easily be browsed. This list is sorted by distance (the</span>
<span class="sd"> closest room to the specified position is always at the top</span>
<span class="sd"> of the list).</span>
<span class="sd"> Args:</span>
<span class="sd"> x (int): the X coord.</span>
<span class="sd"> y (int): the Y coord.</span>
<span class="sd"> z (int): the Z coord.</span>
<span class="sd"> distance (int): the maximum distance to the specified position.</span>
<span class="sd"> Returns:</span>
<span class="sd"> A list of tuples containing the distance to the specified</span>
<span class="sd"> position and the room at this distance. Several rooms</span>
<span class="sd"> can be at equal distance from the position.</span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="c1"># Performs a quick search to only get rooms in a square</span>
<span class="n">x_r</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="nb">reversed</span><span class="p">([</span><span class="nb">str</span><span class="p">(</span><span class="n">x</span> <span class="o">-</span> <span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">distance</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)]))</span>
<span class="n">x_r</span> <span class="o">+=</span> <span class="p">[</span><span class="nb">str</span><span class="p">(</span><span class="n">x</span> <span class="o">+</span> <span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">distance</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)]</span>
<span class="n">y_r</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="nb">reversed</span><span class="p">([</span><span class="nb">str</span><span class="p">(</span><span class="n">y</span> <span class="o">-</span> <span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">distance</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)]))</span>
<span class="n">y_r</span> <span class="o">+=</span> <span class="p">[</span><span class="nb">str</span><span class="p">(</span><span class="n">y</span> <span class="o">+</span> <span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">distance</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)]</span>
<span class="n">z_r</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="nb">reversed</span><span class="p">([</span><span class="nb">str</span><span class="p">(</span><span class="n">z</span> <span class="o">-</span> <span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">distance</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)]))</span>
<span class="n">z_r</span> <span class="o">+=</span> <span class="p">[</span><span class="nb">str</span><span class="p">(</span><span class="n">z</span> <span class="o">+</span> <span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">distance</span> <span class="o">+</span> <span class="mi">1</span><span class="p">)]</span>
<span class="n">wide</span> <span class="o">=</span> <span class="bp">cls</span><span class="o">.</span><span class="n">objects</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span>
<span class="n">db_tags__db_key__in</span><span class="o">=</span><span class="n">x_r</span><span class="p">,</span> <span class="n">db_tags__db_category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span>
<span class="n">db_tags__db_key__in</span><span class="o">=</span><span class="n">y_r</span><span class="p">,</span> <span class="n">db_tags__db_category</span><span class="o">=</span><span class="s2">&quot;coordy&quot;</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span>
<span class="n">db_tags__db_key__in</span><span class="o">=</span><span class="n">z_r</span><span class="p">,</span> <span class="n">db_tags__db_category</span><span class="o">=</span><span class="s2">&quot;coordz&quot;</span><span class="p">)</span>
<span class="c1"># We now need to filter down this list to find out whether</span>
<span class="c1"># these rooms are really close enough, and at what distance</span>
<span class="c1"># In short: we change the square to a circle.</span>
<span class="n">rooms</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">room</span> <span class="ow">in</span> <span class="n">wide</span><span class="p">:</span>
<span class="n">x2</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">room</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordx&quot;</span><span class="p">))</span>
<span class="n">y2</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">room</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordy&quot;</span><span class="p">))</span>
<span class="n">z2</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="n">room</span><span class="o">.</span><span class="n">tags</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="n">category</span><span class="o">=</span><span class="s2">&quot;coordz&quot;</span><span class="p">))</span>
<span class="n">distance_to_room</span> <span class="o">=</span> <span class="n">sqrt</span><span class="p">(</span>
<span class="p">(</span><span class="n">x2</span> <span class="o">-</span> <span class="n">x</span><span class="p">)</span> <span class="o">**</span> <span class="mi">2</span> <span class="o">+</span> <span class="p">(</span><span class="n">y2</span> <span class="o">-</span> <span class="n">y</span><span class="p">)</span> <span class="o">**</span> <span class="mi">2</span> <span class="o">+</span> <span class="p">(</span><span class="n">z2</span> <span class="o">-</span> <span class="n">z</span><span class="p">)</span> <span class="o">**</span> <span class="mi">2</span><span class="p">)</span>
<span class="k">if</span> <span class="n">distance_to_room</span> <span class="o">&lt;=</span> <span class="n">distance</span><span class="p">:</span>
<span class="n">rooms</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">distance_to_room</span><span class="p">,</span> <span class="n">room</span><span class="p">))</span>
<span class="c1"># Finally sort the rooms by distance</span>
<span class="n">rooms</span><span class="o">.</span><span class="n">sort</span><span class="p">(</span><span class="n">key</span><span class="o">=</span><span class="k">lambda</span> <span class="n">tup</span><span class="p">:</span> <span class="n">tup</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
<span class="k">return</span> <span class="n">rooms</span>
</pre></div>
</div>
<p>This gets more serious.</p>
<ol class="simple">
<li><p>We have specified coordinates as parameters. We determine a broad range using the distance.
That is, for each coordinate, we create a list of possible matches. See the example below.</p></li>
<li><p>We then search for the rooms within this broader range. It gives us a square
around our location. Some rooms are definitely outside the range. Again, see the example below
to follow the logic.</p></li>
<li><p>We filter down the list and sort it by distance from the specified coordinates.</p></li>
</ol>
<p>Notice that we only search starting at step 2. Thus, the Django search doesn’t look and cache all
objects, just a wider range than what would be really necessary. This method returns a circle of
coordinates around a specified point. Django looks for a square. What wouldn’t fit in the circle
is removed at step 3, which is the only part that includes systematic calculation. This method is
optimized to be quick and efficient.</p>
</section>
<section id="an-example">
<h3>An example<a class="headerlink" href="#an-example" title="Permalink to this headline"></a></h3>
<p>An example might help. Consider this very simple map (a textual description follows):</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="mi">4</span> <span class="n">A</span> <span class="n">B</span> <span class="n">C</span> <span class="n">D</span>
<span class="mi">3</span> <span class="n">E</span> <span class="n">F</span> <span class="n">G</span> <span class="n">H</span>
<span class="mi">2</span> <span class="n">I</span> <span class="n">J</span> <span class="n">K</span> <span class="n">L</span>
<span class="mi">1</span> <span class="n">M</span> <span class="n">N</span> <span class="n">O</span> <span class="n">P</span>
<span class="mi">1</span> <span class="mi">2</span> <span class="mi">3</span> <span class="mi">4</span>
</pre></div>
</div>
<p>The X coordinates are given below. The Y coordinates are given on the left. This is a simple
square with 16 rooms: 4 on each line, 4 lines of them. All the rooms are identified by letters in
this example: the first line at the top has rooms A to D, the second E to H, the third I to L and
the fourth M to P. The bottom-left room, X=1 and Y=1, is M. The upper-right room X=4 and Y=4 is D.</p>
<p>So let’s say we want to find all the neighbors, distance 1, from the room J. J is at X=2, Y=2.</p>
<p>So we use:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Room.get_rooms_around(x=2, y=2, z=0, distance=1)
# we&#39;ll assume a z coordinate of 0 for simplicity
</pre></div>
</div>
<ol class="simple">
<li><p>First, this method gets all the rooms in a square around J. So it gets E F G, I J K, M N O. If
you want, draw the square around these coordinates to see what’s happening.</p></li>
<li><p>Next, we browse over this list and check the real distance between J (X=2, Y=2) and the room.
The four corners of the square are not in this circle. For instance, the distance between J and M
is not 1. If you draw a circle of center J and radius 1, you’ll notice that the four corners of our
square (E, G, M and O) are not in this circle. So we remove them.</p></li>
<li><p>We sort by distance from J.</p></li>
</ol>
<p>So in the end we might obtain something like this:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="p">[</span>
<span class="p">(</span><span class="mi">0</span><span class="p">,</span> <span class="n">J</span><span class="p">),</span> <span class="c1"># yes, J is part of this circle after all, with a distance of 0</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">F</span><span class="p">),</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">I</span><span class="p">),</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">K</span><span class="p">),</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">N</span><span class="p">),</span>
<span class="p">]</span>
</pre></div>
</div>
<p>You can try with more examples if you want to see this in action.</p>
</section>
<section id="to-conclude">
<h3>To conclude<a class="headerlink" href="#to-conclude" title="Permalink to this headline"></a></h3>
<p>You can definitely use this system to map other objects, not just rooms. You can easily remove the
`Z coordinate too, if you simply need X and Y.</p>
</section>
</section>
</section>
<div class="clearer"></div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<p class="logo"><a href="index.html">
<img class="logo" src="_static/evennia_logo.png" alt="Logo"/>
</a></p>
<div id="searchbox" style="display: none" role="search">
<h3 id="searchlabel">Quick search</h3>
<div class="searchformwrapper">
<form class="search" action="search.html" method="get">
<input type="text" name="q" aria-labelledby="searchlabel" />
<input type="submit" value="Go" />
</form>
</div>
</div>
<script>$('#searchbox').show(0);</script>
<p><h3><a href="index.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Coordinates</a></li>
<li><a class="reference internal" href="#adding-room-coordinates-in-your-game">Adding room coordinates in your game</a><ul>
<li><a class="reference internal" href="#coordinates-as-tags">Coordinates as tags</a></li>
<li><a class="reference internal" href="#some-additional-searches">Some additional searches</a><ul>
<li><a class="reference internal" href="#finding-one-room">Finding one room</a></li>
<li><a class="reference internal" href="#finding-several-rooms">Finding several rooms</a></li>
<li><a class="reference internal" href="#an-example">An example</a></li>
<li><a class="reference internal" href="#to-conclude">To conclude</a></li>
</ul>
</li>
</ul>
</li>
</ul>
<div role="note" aria-label="source link">
<!--h3>This Page</h3-->
<ul class="this-page-menu">
<li><a href="_sources/Coordinates.md.txt"
rel="nofollow">Show Page Source</a></li>
</ul>
</div><h3>Links</h3>
<ul>
<li><a href="https://www.evennia.com">Home page</a> </li>
<li><a href="https://github.com/evennia/evennia">Evennia Github</a> </li>
<li><a href="http://games.evennia.com">Game Index</a> </li>
<li><a href="http://webchat.freenode.net/?channels=evennia&uio=MT1mYWxzZSY5PXRydWUmMTE9MTk1JjEyPXRydWUbb">IRC</a> -
<a href="https://discord.gg/NecFePw">Discord</a> -
<a href="https://groups.google.com/forum/#%21forum/evennia">Forums</a>
</li>
<li><a href="http://evennia.blogspot.com/">Evennia Dev blog</a> </li>
</ul>
<h3>Versions</h3>
<ul>
<li><a href="../1.0-dev/index.html">1.0-dev (develop branch)</a></li>
<li><a href="Coordinates.html">0.9.5 (v0.9.5 branch)</a></li>
</ul>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Python Module Index"
>modules</a> |</li>
<li class="nav-item nav-item-0"><a href="index.html">Evennia 0.9.5</a> &#187;</li>
<li class="nav-item nav-item-this"><a href="">Coordinates</a></li>
</ul>
</div>
<div class="footer" role="contentinfo">
&#169; Copyright 2020, The Evennia developer community.
Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 3.2.1.
</div>
</body>
</html>
Reference in a new issue View git blame Copy permalink