overte/libraries/fbx/src/FBXWriter.cpp

//
//  FBXWriter.cpp
//  libraries/fbx/src
//
//  Created by Ryan Huffman on 9/5/17.
//  Copyright 2017 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

#include "FBXWriter.h"

#include <QDebug>

#ifdef USE_FBX_2016_FORMAT
    using FBXEndOffset = int64_t;
    using FBXPropertyCount = uint64_t;
    using FBXListLength = uint64_t;
#else
    using FBXEndOffset = int32_t;
    using FBXPropertyCount = uint32_t;
    using FBXListLength = uint32_t;
#endif

template <typename T>
void writeVector(QDataStream& out, char ch, QVector<T> vec) {
    // Minimum number of bytes to consider compressing
    const int ATTEMPT_COMPRESSION_THRESHOLD_BYTES = 2000;

    out.device()->write(&ch, 1);
    out << (int32_t)vec.length();

    auto data { QByteArray::fromRawData((const char*)vec.constData(), vec.length() * sizeof(T)) };

    if (data.size() >= ATTEMPT_COMPRESSION_THRESHOLD_BYTES) {
        auto compressedDataWithLength { qCompress(data) };

        // qCompress packs a length uint32 at the beginning of the buffer, but the FBX format
        // does not expect it. This removes it.
        auto compressedData = QByteArray::fromRawData(
            compressedDataWithLength.constData() + sizeof(uint32_t), compressedDataWithLength.size() - sizeof(uint32_t));

        if (compressedData.size() < data.size()) {
            out << FBX_PROPERTY_COMPRESSED_FLAG;
            out << (int32_t)compressedData.size();
            out.writeRawData(compressedData.constData(), compressedData.size());
            return;
        }
    }

    out << FBX_PROPERTY_UNCOMPRESSED_FLAG;
    out << (int32_t)0;
    out.writeRawData(data.constData(), data.size());
}


QByteArray FBXWriter::encodeFBX(const FBXNode& root) {
    QByteArray data;
    QDataStream out(&data, QIODevice::WriteOnly);
    out.setByteOrder(QDataStream::LittleEndian);
    out.setVersion(QDataStream::Qt_4_5);

    out.writeRawData(FBX_BINARY_PROLOG, FBX_BINARY_PROLOG.size());
    out.writeRawData(FBX_BINARY_PROLOG2, FBX_BINARY_PROLOG2.size());

#ifdef USE_FBX_2016_FORMAT
    out << FBX_VERSION_2016;
#else
    out << FBX_VERSION_2015;
#endif

    for (auto& child : root.children) {
        encodeNode(out, child);
    }
    encodeNode(out, FBXNode());

    return data;
}

void FBXWriter::encodeNode(QDataStream& out, const FBXNode& node) {
    auto device = out.device();
    auto nodeStartPos = device->pos();

    // endOffset (temporary, updated later)
    out << (FBXEndOffset)0;

    // Property count
    out << (FBXPropertyCount)node.properties.size();

    // Property list length (temporary, updated later)
    out << (FBXListLength)0;

    out << (quint8)node.name.size();
    out.writeRawData(node.name, node.name.size());

    auto nodePropertiesStartPos = device->pos();

    for (const auto& prop : node.properties) {
        encodeFBXProperty(out, prop);
    }

    // Go back and write property list length
    auto nodePropertiesEndPos = device->pos();
    device->seek(nodeStartPos + sizeof(FBXEndOffset) + sizeof(FBXPropertyCount));
    out << (FBXListLength)(nodePropertiesEndPos - nodePropertiesStartPos);

    device->seek(nodePropertiesEndPos);

    for (auto& child : node.children) {
        encodeNode(out, child);
    }

    if (node.children.length() > 0) {
        encodeNode(out, FBXNode());
    }

    // Go back and write actual endOffset
    auto nodeEndPos = device->pos();
    device->seek(nodeStartPos);
    out << (FBXEndOffset)(nodeEndPos);

    device->seek(nodeEndPos);
}

void FBXWriter::encodeFBXProperty(QDataStream& out, const QVariant& prop) {
    auto type = prop.userType();
    switch (type) {
        case QMetaType::Short:
            out.device()->write("Y", 1);
            out << prop.value<int16_t>();
            break;

        case QVariant::Type::Bool:
            out.device()->write("C", 1);
            out << prop.toBool();
            break;

        case QMetaType::Int:
            out.device()->write("I", 1);
            out << prop.toInt();
            break;

        case QMetaType::Float:
            out.device()->write("F", 1);
            out << prop.toFloat();
            break;

        case QMetaType::Double:
            out.device()->write("D", 1);
            out << prop.toDouble();
            break;

        case QMetaType::LongLong:
            out.device()->write("L", 1);
            out << prop.toLongLong();
            break;

        case QMetaType::QString:
        {
            auto bytes = prop.toString().toUtf8();
            out.device()->write("S", 1);
            out << (int32_t)bytes.size();
            out.writeRawData(bytes, bytes.size());
            break;
        }
        case QMetaType::QByteArray:
        {
            auto bytes = prop.toByteArray();
            out.device()->write("S", 1);
            out << (int32_t)bytes.size();
            out.writeRawData(bytes, bytes.size());
            break;
        }
        default:
        {
            if (prop.canConvert<QVector<float>>()) {
                writeVector(out, 'f', prop.value<QVector<float>>());
            } else if (prop.canConvert<QVector<double>>()) {
                writeVector(out, 'd', prop.value<QVector<double>>());
            } else if (prop.canConvert<QVector<qint64>>()) {
                writeVector(out, 'l', prop.value<QVector<qint64>>());
            } else if (prop.canConvert<QVector<qint32>>()) {
                writeVector(out, 'i', prop.value<QVector<qint32>>());
            } else if (prop.canConvert<QVector<bool>>()) {
                writeVector(out, 'b', prop.value<QVector<bool>>());
            } else {
                qDebug() << "Unsupported property type in FBXWriter::encodeNode: " << type << prop;
                throw("Unsupported property type in FBXWriter::encodeNode: " + QString::number(type) + " " + prop.toString());
            }
        }

    }
}