/** 
* @file llmeshoptimizer.cpp
* @brief Wrapper around meshoptimizer
*
* $LicenseInfo:firstyear=2021&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2021, Linden Research, Inc.
* 
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
* 
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
* 
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
* 
* Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
* $/LicenseInfo$
*/

#include "llmeshoptimizer.h"

#include "meshoptimizer.h"

LLMeshOptimizer::LLMeshOptimizer()
{
    // Todo: Looks like for memory management, we can add allocator and deallocator callbacks
    // Should be one time
    // meshopt_setAllocator(allocate, deallocate);
}

LLMeshOptimizer::~LLMeshOptimizer()
{
}

//static
U64 LLMeshOptimizer::simplify(U16 *destination,
                              const U16 *indices,
                              U64 index_count,
                              const LLVector4a *vertex_positions,
                              U64 vertex_count,
                              U64 target_index_count,
                              F32 target_error,
                              F32* result_error
    )
{
    const size_t vertex_stride = 4; // should be either 0 or 4

    // Consider running meshopt_generateShadowIndexBuffer<unsigned short> first.
    // meshopt_generateShadowIndexBuffer is only needed if models don't use some of the vertices,
    // but since we call optimize() in a lot of cases, it likely isn't needed
    return meshopt_simplify<unsigned short>(destination,
                                 indices,
                                 index_count,
                                 (const float*)vertex_positions, // verify that it is correct to convert to float
                                 vertex_count,
                                 vertex_stride, 
                                 target_index_count,
                                 target_error,
                                 result_error
                                 );
}

//static
U64 LLMeshOptimizer::simplifySloppy(U16 *destination,
                              const U16 *indices,
                              U64 index_count,
                              const LLVector4a *vertex_positions,
                              U64 vertex_count,
                              U64 target_index_count,
                              F32 target_error,
                              F32* result_error
    )
{
    const size_t vertex_stride = 4; // should be either 0 or 4
    return meshopt_simplifySloppy<unsigned short>(destination,
                                 indices,
                                 index_count,
                                 (const float*)vertex_positions, // verify that it is correct to convert to float
                                 vertex_count,
                                 vertex_stride, 
                                 target_index_count,
                                 target_error,
                                 result_error
                                 );
}