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14 <h1>QVM: Quaternions, Vectors, Matrices
</h1>
16 <!-- Copyright (c) 2008-2016 Emil Dotchevski and Reverge Studios, Inc. -->
17 <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying -->
18 <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
19 <div class=
"RenoIncludeDIV"><div class=
"RenoAutoDIV"><h3>Swizzling
</h3>
21 <p>Boost QVM allows
<span class=
"RenoLink"><a href=
"accessing_vector_elements_and_swizzling_reference.html">accessing vector elements by swizzling
</a></span>, exposing vector views of different dimensions, and/or views with reordered elements. The example below rotates
<i>v
</i> around the X axis, and stores the resulting vector back in
<i>v
</i> but with the X and Y elements swapped:
</p>
22 <pre>float3 v = {
0,
0,
7};
23 <span class=
"RenoLink"><a href=
"accessing_vector_elements_and_swizzling_reference.html">YXZ
</a></span>(v) =
<span class=
"RenoLink"><a href=
"rotx_mat_scalar_.html">rotx_mat
</a></span><3>(
3.14159f)
<span class=
"RenoLink"><a href=
"operator_times_mat_vec_.html">*
</a></span> v;
</pre>
24 <p>A special case of swizzling provides next-dimension-view of a vector object, adding either
0 or
1 as its last component. Assuming
<i>float3
</i> is a
3D vector type, and
<i>float4
</i> is a
4D vector type, the following statements are valid:
</p>
25 <pre>float3 v = {
0,
0,
7};
26 float4 point =
<span class=
"RenoLink"><a href=
"accessing_vector_elements_and_swizzling_reference.html">XYZ1
</a></span>(v); //{
0,
0,
7,
1}
27 float4 vector =
<span class=
"RenoLink"><a href=
"accessing_vector_elements_and_swizzling_reference.html">XYZ0
</a></span>(v); //{
0,
0,
7,
0}
</pre>
28 <p>It is also valid for swizzling to address vector elements more than once:
</p>
29 <pre>float3 v = {
0,
0,
7};
30 float4 v1 =
<span class=
"RenoLink"><a href=
"accessing_vector_elements_and_swizzling_reference.html">ZZZZ
</a></span>(v); //{
7,
7,
7,
7}
</pre>
31 <p>Boost QVM defines all permutations of
<i>X
</i>,
<i>Y
</i>,
<i>Z
</i>,
<i>W
</i> for
1D,
2D,
3D and
4D swizzling, plus each dimension defines variants with
<i>0</i> or
<i>1</i> used at any position (if
0 or
1 appear at the first position, the swizzling function name begins with underscore, e.g.
<i>_1XY
</i>).
</p>
32 </div><div class=
"RenoIncludeDIV"><div class=
"RenoHR"><hr/></div>
33 <p><b>Tutorial navigation:
</b> <span class=
"RenoLink"><a href=
"quaternions_vectors_matrices.html">Quaternions, Vectors, Matrices
</a></span> |
<span class=
"RenoLink"><a href=
"c_arrays.html">C Arrays
</a></span> |
<span class=
"RenoLink"><a href=
"Views.html">Views
</a></span> |
<span class=
"RenoLink">Swizzling
</span> |
<span class=
"RenoLink"><a href=
"Interoperability.html">Interoperability
</a></span><span class=
"RenoBR"> </span><br/><span class=
"RenoBR"> </span><br/>See also:
<span class=
"RenoLink"><a href=
"index.html">Boost QVM
</a></span></p>
34 </div><!-- Copyright (c) 2008-2016 Emil Dotchevski and Reverge Studios, Inc. -->
35 <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying -->
36 <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
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41 <small>Copyright (c)
2008-
2016 by Emil Dotchevski and Reverge Studios, Inc.
<br/>
42 Distributed under the
<a href=
"http://www.boost.org/LICENSE_1_0.txt">Boost Software License, Version
1.0</a>.
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