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/*
Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
This file is part of Magnum.
Magnum is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License version 3
only, as published by the Free Software Foundation.
Magnum 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 version 3 for more details.
*/
#include "CompressIndices.h"
#include <cstring>
#include <algorithm>
#include "Math/Functions.h"
namespace Magnum { namespace MeshTools {
#ifndef DOXYGEN_GENERATING_OUTPUT
namespace {
template<class> constexpr Mesh::IndexType indexType();
template<> inline constexpr Mesh::IndexType indexType<GLubyte>() { return Mesh::IndexType::UnsignedByte; }
template<> inline constexpr Mesh::IndexType indexType<GLushort>() { return Mesh::IndexType::UnsignedShort; }
template<> inline constexpr Mesh::IndexType indexType<GLuint>() { return Mesh::IndexType::UnsignedInt; }
template<class T> inline std::tuple<std::size_t, Mesh::IndexType, char*> compress(const std::vector<std::uint32_t>& indices) {
char* buffer = new char[indices.size()*sizeof(T)];
for(std::size_t i = 0; i != indices.size(); ++i) {
T index = static_cast<T>(indices[i]);
std::memcpy(buffer+i*sizeof(T), &index, sizeof(T));
}
return std::make_tuple(indices.size(), indexType<T>(), buffer);
}
}
#endif
std::tuple<std::size_t, Mesh::IndexType, char*> compressIndices(const std::vector<std::uint32_t>& indices) {
std::size_t size = *std::max_element(indices.begin(), indices.end());
switch(Math::log(256, size)) {
case 0:
return compress<GLubyte>(indices);
case 1:
return compress<GLushort>(indices);
case 2:
case 3:
return compress<GLuint>(indices);
default:
CORRADE_ASSERT(false, "MeshTools::compressIndices(): no type able to index" << size << "elements.", {});
}
}
void compressIndices(Mesh* mesh, Buffer* buffer, Buffer::Usage usage, const std::vector<std::uint32_t>& indices) {
std::size_t indexCount;
Mesh::IndexType indexType;
char* data;
std::tie(indexCount, indexType, data) = compressIndices(indices);
mesh->setIndexCount(indices.size())
->setIndexBuffer(buffer, 0, indexType);
buffer->setData(indexCount*Mesh::indexSize(indexType), data, usage);
delete[] data;
}
}}