projects / ceph.git / blame
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| 7c673cae FG |
1 | <!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Strict//EN' |
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| 4 | <head> | |
| 5 | <meta http-equiv='Content-Type' content='text/html; charset=utf-8'/> | |
| 6 | <title>accessing vector elements by swizzling</title> | |
| 7 | <link href='reno.css' type='text/css' rel='stylesheet'/> | |
| 8 | </head> | |
| 9 | <body> | |
| 10 | <div class="body-0"> | |
| 11 | <div class="body-1"> | |
| 12 | <div class="body-2"> | |
| 13 | <div> | |
| 14 | <h1>QVM: Quaternions, Vectors, Matrices</h1> | |
| 15 | </div> | |
| 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>Accessing Vector Elements by Swizzling</h3> | |
| 20 | </div> | |
| 21 | <div class="RenoIncludeDIV"><p><span class="RenoEscape">#<!--<wiki>`#</wiki>--></span>include <<span class="RenoLink"><a href="boost_qvm_swizzle_hpp.html">boost/qvm/swizzle.hpp</a></span>></p> | |
| 22 | <pre>namespace boost | |
| 23 | { | |
| 24 | namespace <span class="RenoLink"><a href="qvm.html">qvm</a></span> | |
| 25 | { | |
| 26 | <span class="RenoIncludeSPAN"> //*** Accessing vector elements by swizzling *** | |
| 27 | ||
| 28 | <span class="RenoIncludeSPAN">//2D <span class="RenoLink"><a href="view_proxy.html">view proxies</a></span>, only <span class="RenoLink"><a href="SFINAE_enable_if.html">enabled if</a></span>: | |
| 29 | // <span class="RenoLink"><a href="is_vec.html">is_vec</a></span><V>::value | |
| 30 | template <class V> -unspecified-2D-vector-type- XX( V & v ); | |
| 31 | template <class V> -unspecified-2D-vector-type- XY( V & v ); | |
| 32 | template <class V> -unspecified-2D-vector-type- XZ( V & v ); | |
| 33 | template <class V> -unspecified-2D-vector-type- XW( V & v ); | |
| 34 | template <class V> -unspecified-2D-vector-type- X0( V & v ); | |
| 35 | template <class V> -unspecified-2D-vector-type- X1( V & v ); | |
| 36 | template <class V> -unspecified-2D-vector-type- YX( V & v ); | |
| 37 | template <class V> -unspecified-2D-vector-type- YY( V & v ); | |
| 38 | template <class V> -unspecified-2D-vector-type- YZ( V & v ); | |
| 39 | template <class V> -unspecified-2D-vector-type- YW( V & v ); | |
| 40 | template <class V> -unspecified-2D-vector-type- Y0( V & v ); | |
| 41 | template <class V> -unspecified-2D-vector-type- Y1( V & v ); | |
| 42 | template <class V> -unspecified-2D-vector-type- ZX( V & v ); | |
| 43 | template <class V> -unspecified-2D-vector-type- ZY( V & v ); | |
| 44 | template <class V> -unspecified-2D-vector-type- ZZ( V & v ); | |
| 45 | template <class V> -unspecified-2D-vector-type- ZW( V & v ); | |
| 46 | template <class V> -unspecified-2D-vector-type- Z0( V & v ); | |
| 47 | template <class V> -unspecified-2D-vector-type- Z1( V & v ); | |
| 48 | template <class V> -unspecified-2D-vector-type- WX( V & v ); | |
| 49 | template <class V> -unspecified-2D-vector-type- WY( V & v ); | |
| 50 | template <class V> -unspecified-2D-vector-type- WZ( V & v ); | |
| 51 | template <class V> -unspecified-2D-vector-type- WW( V & v ); | |
| 52 | template <class V> -unspecified-2D-vector-type- W0( V & v ); | |
| 53 | template <class V> -unspecified-2D-vector-type- W1( V & v ); | |
| 54 | ... | |
| 55 | -unspecified-2D-vector-type- _00(); | |
| 56 | -unspecified-2D-vector-type- _01(); | |
| 57 | -unspecified-2D-vector-type- _10(); | |
| 58 | -unspecified-2D-vector-type- _11(); | |
| 59 | ||
| 60 | //3D <span class="RenoLink"><a href="view_proxy.html">view proxies</a></span>, only <span class="RenoLink"><a href="SFINAE_enable_if.html">enabled if</a></span>: | |
| 61 | // <span class="RenoLink"><a href="is_vec.html">is_vec</a></span><V>::value | |
| 62 | template <class V> -unspecified-3D-vector-type- XXX( V & v ); | |
| 63 | ... | |
| 64 | template <class V> -unspecified-3D-vector-type- XXW( V & v ); | |
| 65 | template <class V> -unspecified-3D-vector-type- XX0( V & v ); | |
| 66 | template <class V> -unspecified-3D-vector-type- XX1( V & v ); | |
| 67 | template <class V> -unspecified-3D-vector-type- XYX( V & v ); | |
| 68 | ... | |
| 69 | template <class V> -unspecified-3D-vector-type- XY1( V & v ); | |
| 70 | ... | |
| 71 | template <class V> -unspecified-3D-vector-type- WW1( V & v ); | |
| 72 | ... | |
| 73 | -unspecified-3D-vector-type- _000(); | |
| 74 | -unspecified-3D-vector-type- _001(); | |
| 75 | -unspecified-3D-vector-type- _010(); | |
| 76 | ... | |
| 77 | -unspecified-3D-vector-type- _111(); | |
| 78 | ||
| 79 | //4D <span class="RenoLink"><a href="view_proxy.html">view proxies</a></span>, only <span class="RenoLink"><a href="SFINAE_enable_if.html">enabled if</a></span>: | |
| 80 | // <span class="RenoLink"><a href="is_vec.html">is_vec</a></span><V>::value | |
| 81 | template <class V> -unspecified-4D-vector-type- XXXX( V & v ); | |
| 82 | ... | |
| 83 | template <class V> -unspecified-4D-vector-type- XXXW( V & v ); | |
| 84 | template <class V> -unspecified-4D-vector-type- XXX0( V & v ); | |
| 85 | template <class V> -unspecified-4D-vector-type- XXX1( V & v ); | |
| 86 | template <class V> -unspecified-4D-vector-type- XXYX( V & v ); | |
| 87 | ... | |
| 88 | template <class V> -unspecified-4D-vector-type- XXY1( V & v ); | |
| 89 | ... | |
| 90 | template <class V> -unspecified-4D-vector-type- WWW1( V & v ); | |
| 91 | ... | |
| 92 | -unspecified-4D-vector-type- _0000(); | |
| 93 | -unspecified-4D-vector-type- _0001(); | |
| 94 | -unspecified-4D-vector-type- _0010(); | |
| 95 | ... | |
| 96 | -unspecified-4D-vector-type- _1111();</span> </span> | |
| 97 | } | |
| 98 | }</pre> | |
| 99 | </div><p>Swizzling allows zero-overhead direct access to a (possibly rearranged) subset of the elements of 2D, 3D and 4D vectors. For example, if <i>v</i> is a 4D vector, the expression <i>(v,YX)</i> is a 2D <span class="RenoLink"><a href="view_proxy.html">view proxy</a></span> whose <i>X</i> element refers to the <i>Y</i> element of <i>v</i>, and whose <i>Y</i> element refers to the <i>X</i> element of <i>v</i>. Like other <span class="RenoLink"><a href="view_proxy.html">view proxies</a></span> <i>YX</i> is an lvalue, that is, if <i>v2</i> is a 2D vector, one could write:</p> | |
| 100 | <pre>YX(v) = v2;</pre> | |
| 101 | <p>The above will leave the <i>Z</i> and <i>W</i> elements of <i>v</i> unchanged but assign the <i>Y</i> element of <i>v2</i> to the <i>X</i> element of <i>v</i> and the <i>X</i> element of <i>v2</i> to the <i>Y</i> element of <i>v</i>.</p> | |
| 102 | <p>It is also possible to repeat the same vector element in rvalue swizzling: the expression <i>ZZZ(v)</i> is a 3D vector whose <i>X</i>, <i>Y</i> and <i>Z</i> elements all refer to the <i>Z</i> element of <i>v</i>.</p> | |
| 103 | </div><div class="RenoAutoDIV"><div class="RenoHR"><hr/></div> | |
| 104 | See also: <span class="RenoPageList"><a href="index.html">Boost QVM</a> | <a href="boost_qvm_swizzle2_hpp.html">boost/qvm/swizzle2.hpp</a> | <a href="boost_qvm_swizzle3_hpp.html">boost/qvm/swizzle3.hpp</a> | <a href="boost_qvm_swizzle4_hpp.html">boost/qvm/swizzle4.hpp</a> | <a href="Synopsis.html">Synopsis</a> | <a href="transform_point.html">transform_point</a> | <a href="transform_vector.html">transform_vector</a></span> | |
| 105 | </div> | |
| 106 | <!-- Copyright (c) 2008-2016 Emil Dotchevski and Reverge Studios, Inc. --> | |
| 107 | <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying --> | |
| 108 | <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> | |
| 109 | <div id="footer"> | |
| 110 | <p> | |
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| 113 | <small>Copyright (c) 2008-2016 by Emil Dotchevski and Reverge Studios, Inc.<br/> | |
| 114 | Distributed under the <a href="http://www.boost.org/LICENSE_1_0.txt">Boost Software License, Version 1.0</a>.</small> | |
| 115 | </p> | |
| 116 | </div> | |
| 117 | </div> | |
| 118 | </div> | |
| 119 | </div> | |
| 120 | </body> | |
| 121 | </html> |