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

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

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    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
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*/

/** @file
 * @brief Function @ref Magnum::MeshTools::combineIndexedAttributes()
 * @m_since_latest
 */

#include <initializer_list>

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

namespace Magnum { namespace MeshTools {

/**
@brief Combine differently indexed attributes into a single mesh
@m_since_latest

Assuming each @p data contains only unique vertex data, creates an indexed mesh
that contains all attributes from @p data combined, with duplicate vertices
removed. For example, when you have a position and a normal array, each indexed
with separate indices like this:

@code{.cpp}
{pA, pB, pC, pD, pE, pF}        // positions
{nA, nB, nC, nD, nE, nF, nG}    // normals

{0, 2, 5, 0, 0, 1, 3, 2, 2}     // position indices
{1, 3, 4, 1, 4, 6, 1, 3, 1}     // normal indices
@endcode

Then the first triangle in the mesh is defined as
@cb{.cpp} {pA, nB}, {pC, nD}, {pF, nE} @ce. When combined together using this
function, the resulting mesh stays the same but there's just one index array,
indexing both positions and normals:

@code{.cpp}
{{pA, nB}, {pC, nD}, {pF, nE}, {pA, nE}, {pB, nG}, {pD, nB}, {pC, nB}}
                                // unique pairs of positions and normals

{0, 1, 2, 0, 3, 4, 5, 1, 6}     // unified indices
@endcode

The function preserves all vertex data including repeated or custom attributes.
The resulting mesh is interleaved, with all attributes packed tightly together.
If you need to add specific padding for alignment preservation, pass the result
to @ref interleave() and specify the paddings between attributes manually.
Similarly, for simplicity the resulting mesh has always
@ref MeshIndexType::UnsignedInt --- use @ref compressIndices(const Trade::MeshData&, MeshIndexType)
if you want to have it compressed to a smaller type.

Expects that @p data is non-empty and all data have the same primitive and
index count. All inputs have to be indexed, although the particular
@ref MeshIndexType doesn't matter. For non-indexed attributes combining can be
done much more efficiently using @ref duplicate(const Trade::MeshData&, Containers::ArrayView<const Trade::MeshAttributeData>),
alternatively you can turn a non-indexed attribute to an indexed one first
using @ref removeDuplicatesInPlace() and then call this function.
*/
MAGNUM_MESHTOOLS_EXPORT Trade::MeshData combineIndexedAttributes(const Containers::ArrayView<const Containers::Reference<const Trade::MeshData>> data);

/**
 * @overload
 * @m_since_latest
 */
MAGNUM_MESHTOOLS_EXPORT Trade::MeshData combineIndexedAttributes(std::initializer_list<Containers::Reference<const Trade::MeshData>> data);

}}

#endif