summaryrefslogtreecommitdiff
path: root/manuals/chickadee/Quaternions.html
blob: 8c892551036da94934361752fd8d5b1d6e85480a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Copyright (C) 2017-2020  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 6.6, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Quaternions (The Chickadee Game Toolkit)</title>

<meta name="description" content="Quaternions (The Chickadee Game Toolkit)">
<meta name="keywords" content="Quaternions (The Chickadee Game Toolkit)">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html#Top" rel="start" title="Top">
<link href="Index.html#Index" rel="index" title="Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="Math.html#Math" rel="up" title="Math">
<link href="Easings.html#Easings" rel="next" title="Easings">
<link href="Matrices.html#Matrices" rel="prev" title="Matrices">
<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="Quaternions"></span><div class="header">
<p>
Next: <a href="Easings.html#Easings" accesskey="n" rel="next">Easings</a>, Previous: <a href="Matrices.html#Matrices" accesskey="p" rel="prev">Matrices</a>, Up: <a href="Math.html#Math" accesskey="u" rel="up">Math</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<span id="Quaternions-1"></span><h4 class="subsection">2.2.6 Quaternions</h4>

<p>In game development, the quaternion is most often used to represent
rotations.  Why not use a matrix for that, you may ask.  Unlike
matrices, quaternions can be interpolated (animated) and produce a
meaningful result.  When interpolating two quaternions, there is a
smooth transition from one rotation to another, whereas interpolating
two matrices would yield garbage.
</p>
<dl>
<dt id="index-quaternion">Procedure: <strong>quaternion</strong> <em>x y z w</em></dt>
<dd><p>Return a new quaternion with values <var>x</var>, <var>y</var>, <var>z</var>, and
<var>w</var>.
</p></dd></dl>

<dl>
<dt id="index-quaternion_003f">Procedure: <strong>quaternion?</strong> <em>obj</em></dt>
<dd><p>Return <code>#t</code> if <var>obj</var> is a quaternion.
</p></dd></dl>

<dl>
<dt id="index-quaternion_002dw">Procedure: <strong>quaternion-w</strong> <em>q</em></dt>
<dd><p>Return the W component of the quaternion <var>q</var>.
</p></dd></dl>

<dl>
<dt id="index-quaternion_002dx">Procedure: <strong>quaternion-x</strong> <em>q</em></dt>
<dd><p>Return the X component of the quaternion <var>q</var>.
</p></dd></dl>

<dl>
<dt id="index-quaternion_002dy">Procedure: <strong>quaternion-y</strong> <em>q</em></dt>
<dd><p>Return the Y component of the quaternion <var>q</var>.
</p></dd></dl>

<dl>
<dt id="index-quaternion_002dz">Procedure: <strong>quaternion-z</strong> <em>q</em></dt>
<dd><p>Return the Z component of the quaternion <var>q</var>.
</p></dd></dl>

<dl>
<dt id="index-make_002didentity_002dquaternion">Procedure: <strong>make-identity-quaternion</strong></dt>
<dd><p>Return the identity quaternion.
</p></dd></dl>




</body>
</html>