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diff --git a/manuals/chickadee/Quadtrees.html b/manuals/chickadee/Quadtrees.html new file mode 100644 index 0000000..e6962a4 --- /dev/null +++ b/manuals/chickadee/Quadtrees.html @@ -0,0 +1,222 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 2017-2021 David Thompson davet@gnu.org + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 +or any later version published by the Free Software Foundation; +with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. +A copy of the license is included in the section entitled "GNU +Free Documentation License". + +A copy of the license is also available from the Free Software +Foundation Web site at http://www.gnu.org/licenses/fdl.html. + + +* Chickadee: (chickadee). Game programming toolkit for Guile. + +The document was typeset with +http://www.texinfo.org/ (GNU Texinfo). + --> +<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ --> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<title>Quadtrees (The Chickadee Game Toolkit)</title> + +<meta name="description" content="Quadtrees (The Chickadee Game Toolkit)"> +<meta name="keywords" content="Quadtrees (The Chickadee Game Toolkit)"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<link href="index.html" rel="start" title="Top"> +<link href="Index.html" rel="index" title="Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Data-Structures.html" rel="up" title="Data Structures"> +<link href="Grids.html" rel="next" title="Grids"> +<link href="Heaps.html" rel="prev" title="Heaps"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.indentedblock {margin-right: 0em} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +kbd {font-style: oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +span.nolinebreak {white-space: nowrap} +span.roman {font-family: initial; font-weight: normal} +span.sansserif {font-family: sans-serif; font-weight: normal} +ul.no-bullet {list-style: none} +@media (min-width: 1140px) { + body { + margin-left: 14rem; + margin-right: 4rem; + max-width: 52rem; + } +} + +@media (min-width: 800px) and (max-width: 1140px) { + body { + margin-left: 6rem; + margin-right: 4rem; + max-width: 52rem; + } +} + +@media (max-width: 800px) { + body { + margin: 1rem; + } +} + +--> +</style> +<link rel="stylesheet" type="text/css" href="https://dthompson.us/css/dthompson.css"> + + +</head> + +<body lang="en"> +<span id="Quadtrees"></span><div class="header"> +<p> +Next: <a href="Grids.html" accesskey="n" rel="next">Grids</a>, Previous: <a href="Heaps.html" accesskey="p" rel="prev">Heaps</a>, Up: <a href="Data-Structures.html" accesskey="u" rel="up">Data Structures</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<span id="Quadtrees-1"></span><h4 class="subsection">5.6.4 Quadtrees</h4> + +<p>The <code>(chickadee data quadtree)</code> module provides a 2D spatial +partitioning implementation known as a “quadtree”. A quadtree +recursively subdivides the world into rectangular quadrants. This +data structure is very useful for handling broad-phase collision +detection because it can quickly determine the objects that may +possibly be colliding with another, resulting in fewer narrow-phase +collision tests that are typically much more expensive. +</p> +<dl> +<dt id="index-make_002dquadtree">Procedure: <strong>make-quadtree</strong> <em>bounds [#:max-size 5] [#:max-depth 4]</em></dt> +<dd><p>Return a new quadtree that covers the area <var>bounds</var>. Each node +will try to hold at maximum <var>max-size</var> objects and the tree depth +will be restricted to <var>max-depth</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_003f">Procedure: <strong>quadtree?</strong> <em>obj</em></dt> +<dd><p>Return <code>#t</code> if <var>obj</var> is a quadtree. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dclear_0021">Procedure: <strong>quadtree-clear!</strong> <em>quadtree</em></dt> +<dd><p>Clear all objects from <var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dinsert_0021">Procedure: <strong>quadtree-insert!</strong> <em>quadtree rect object</em></dt> +<dd><p>Insert <var>object</var> with bounding box <var>rect</var> into <var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002ddelete_0021">Procedure: <strong>quadtree-delete!</strong> <em>quadtree rect object</em></dt> +<dd><p>Delete <var>object</var>, who occupies the space <var>rect</var>, from +<var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dfind">Procedure: <strong>quadtree-find</strong> <em>rect pred</em></dt> +<dd><p>Return the first object in <var>quadtree</var> in the vicinity of +<var>rect</var> that satisfies <var>pred</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dfold">Procedure: <strong>quadtree-fold</strong> <em>quadtree rect init proc</em></dt> +<dd><p>Apply <var>proc</var> to all objects in the vicinity of <var>rect</var> in +<var>quadtree</var> to build a result and return that result. <var>init</var> +is the initial result. If there are no objects in the vicinity of +<var>rect</var>, just <var>init</var> is returned. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dfor_002deach">Procedure: <strong>quadtree-for-each</strong> <em>quadtree rect proc</em></dt> +<dd><p>Call <var>proc</var> for all objects in the vicinity of <var>rect</var> in +<var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dleaf_003f">Procedure: <strong>quadtree-leaf?</strong> <em>quadtree</em></dt> +<dd><p>Return <code>#t</code> if <var>quadtree</var> is a leaf node. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dbounds">Procedure: <strong>quadtree-bounds</strong> <em>quadtree</em></dt> +<dd><p>Return the bounding rectangle of <var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dmax_002ddepth">Procedure: <strong>quadtree-max-depth</strong> <em>quadtree</em></dt> +<dd><p>Return the maximum depth of <var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dmax_002dsize">Procedure: <strong>quadtree-max-size</strong> <em>quadtree</em></dt> +<dd><p>Return the desired per-node maximum object count of <var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002ddepth">Procedure: <strong>quadtree-depth</strong> <em>quadtree</em></dt> +<dd><p>Return the depth of the node <var>quadtree</var>. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dsize">Procedure: <strong>quadtree-size</strong> <em>quadtree</em></dt> +<dd><p>Return the number of objects stored in the node <var>quadtree</var>. +</p></dd></dl> + +<p>Non-leaf nodes always have four child nodes, which correspond to the +quadrants of a Cartesian coordinate system: +</p> +<pre class="verbatim">*------*------* +| | | +| Q2 | Q1 | +| | | +*------*------* +| | | +| Q3 | Q4 | +| | | +*------*------* +</pre> +<dl> +<dt id="index-quadtree_002dq1">Procedure: <strong>quadtree-q1</strong> <em>quadtree</em></dt> +<dd><p>Return the upper-right child node of <var>quadtree</var>, or <code>#f</code> if +<var>quadtree</var> is a leaf node. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dq2">Procedure: <strong>quadtree-q2</strong> <em>quadtree</em></dt> +<dd><p>Return the upper-left child node of <var>quadtree</var>, or <code>#f</code> if +<var>quadtree</var> is a leaf node. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dq3">Procedure: <strong>quadtree-q3</strong> <em>quadtree</em></dt> +<dd><p>Return the lower-left child node of <var>quadtree</var>, or <code>#f</code> if +<var>quadtree</var> is a leaf node. +</p></dd></dl> + +<dl> +<dt id="index-quadtree_002dq4">Procedure: <strong>quadtree-q4</strong> <em>quadtree</em></dt> +<dd><p>Return the lower-right child node of <var>quadtree</var>, or <code>#f</code> if +<var>quadtree</var> is a leaf node. +</p></dd></dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Grids.html" accesskey="n" rel="next">Grids</a>, Previous: <a href="Heaps.html" accesskey="p" rel="prev">Heaps</a>, Up: <a href="Data-Structures.html" accesskey="u" rel="up">Data Structures</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |