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74 lines
2.7 KiB
74 lines
2.7 KiB
#ifndef Magnum_Math_Swizzle_h |
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#define Magnum_Math_Swizzle_h |
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/* |
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Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz> |
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This file is part of Magnum. |
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Magnum is free software: you can redistribute it and/or modify |
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it under the terms of the GNU Lesser General Public License version 3 |
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only, as published by the Free Software Foundation. |
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Magnum is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU Lesser General Public License version 3 for more details. |
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*/ |
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/** @file |
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* @brief Function Magnum::Math::swizzle() |
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*/ |
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#include "Vector.h" |
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namespace Magnum { namespace Math { |
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#ifndef DOXYGEN_GENERATING_OUTPUT |
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namespace Implementation { |
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template<std::size_t size, std::size_t position> struct ComponentAtPosition { |
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static_assert(size > position, "Swizzle parameter out of range of base vector"); |
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template<class T> inline constexpr static T value(const Math::Vector<size, T>& vector) { return vector[position]; } |
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}; |
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template<std::size_t size, char component> struct Component {}; |
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template<std::size_t size> struct Component<size, 'x'>: public ComponentAtPosition<size, 0> {}; |
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template<std::size_t size> struct Component<size, 'y'>: public ComponentAtPosition<size, 1> {}; |
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template<std::size_t size> struct Component<size, 'z'>: public ComponentAtPosition<size, 2> {}; |
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template<std::size_t size> struct Component<size, 'w'>: public ComponentAtPosition<size, 3> {}; |
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template<std::size_t size> struct Component<size, '0'> { |
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template<class T> inline constexpr static T value(const Math::Vector<size, T>&) { return T(0); } |
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}; |
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template<std::size_t size> struct Component<size, '1'> { |
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template<class T> inline constexpr static T value(const Math::Vector<size, T>&) { return T(1); } |
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}; |
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} |
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#endif |
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/** |
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@brief Swizzle Vector components |
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Creates new vector from given components. Example: |
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@code |
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Vector4<Int> original(-1, 2, 3, 4); |
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auto vec = swizzle<'w', '1', '0', 'x', 'y', 'z'>(original); |
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// vec == { 4, 1, 0, -1, 2, 3 } |
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@endcode |
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You can use letters `x`, `y`, `z`, `w` for addressing components or letters |
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`0` and `1` for zero and one. Count of elements is unlimited, but must be at |
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least one. |
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See also Magnum::swizzle() which has some added convenience features not |
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present in this lightweight implementation for Math namespace. |
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@see @ref matrix-vector-component-access, Vector4::xyz(), |
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Vector4::xy(), Vector3::xy() |
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*/ |
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template<char ...components, std::size_t size, class T> inline constexpr Vector<sizeof...(components), T> swizzle(const Vector<size, T>& vector) { |
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return {Implementation::Component<size, components>::value(vector)...}; |
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} |
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}} |
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#endif
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