magnum/src/Magnum/MeshTools/FlipNormals.h

#ifndef Magnum_MeshTools_FlipNormals_h
#define Magnum_MeshTools_FlipNormals_h
/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019
              Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

/** @file
 * @brief Function @ref Magnum::MeshTools::flipFaceWinding(), @ref Magnum::MeshTools::flipNormals()
 */

#include <vector>

#include "Magnum/Magnum.h"
#include "Magnum/MeshTools/visibility.h"

namespace Magnum { namespace MeshTools {

/**
@brief Flip face winding
@param[in,out] indices  Index array to operate on

The same as @ref flipNormals(std::vector<UnsignedInt>&, std::vector<Vector3>&),
but flips only face winding.

@attention The function requires the mesh to have triangle faces, thus index
    count must be divisible by 3.
*/
void MAGNUM_MESHTOOLS_EXPORT flipFaceWinding(std::vector<UnsignedInt>& indices);

/**
@brief Flip mesh normals
@param[in,out] normals  Normal array to operate on

The same as @ref flipNormals(std::vector<UnsignedInt>&, std::vector<Vector3>&),
but flips only normals, not face winding.
*/
void MAGNUM_MESHTOOLS_EXPORT flipNormals(std::vector<Vector3>& normals);

/**
@brief Flip mesh normals and face winding
@param[in,out] indices  Index array to operate on
@param[in,out] normals  Normal array to operate on

Flips normal vectors and face winding in index array for face culling to work
properly too. See also @ref flipNormals(std::vector<Vector3>&) and
@ref flipFaceWinding(), which flip normals or face winding only.

@attention The function requires the mesh to have triangle faces, thus index
    count must be divisible by 3.
*/
inline void flipNormals(std::vector<UnsignedInt>& indices, std::vector<Vector3>& normals) {
    flipFaceWinding(indices);
    flipNormals(normals);
}

}}

#endif