projects / ceph.git / blame
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| 7c673cae FG |
1 | <!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Strict//EN' |
| 2 | 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd'> | |
| 3 | <html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en' lang='en'> | |
| 4 | <head> | |
| 5 | <meta http-equiv='Content-Type' content='text/html; charset=utf-8'/> | |
| 6 | <title>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>Swizzling</h3> | |
| 20 | </div> | |
| 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) --> | |
| 37 | <div id="footer"> | |
| 38 | <p> | |
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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>.</small> | |
| 43 | </p> | |
| 44 | </div> | |
| 45 | </div> | |
| 46 | </div> | |
| 47 | </div> | |
| 48 | </body> | |
| 49 | </html> |