instancerepeater.cpp

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// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
 
#include "instancerepeater_p.h"
#include <math.h>
#include <QMatrix4x4>
 
QT_BEGIN_NAMESPACE
 
 
/*
 \table
    \header
        \li Qt Core Feature
        \li Brief Description
    \row
        \li \l {Signal and Slots}
        \li Signals and slots are used for communication
           between objects.
    \row
        \li \l {Layout Management}
        \li The Qt layout system provides a simple
           and powerful way of specifying the layout
           of child widgets.
    \row
        \li \l {Drag and Drop}
        \li Drag and drop provides a simple visual
           mechanism which users can use to transfer
           information between and within applications.
    \endtable
 
   */
 
InstanceModel::InstanceModel(QObject *parent)
    : QAbstractListModel(parent)
{
}
 
QVariant InstanceModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();
    ensureTable();
 
 
    int idx = index.row();
 
    if (idx >= m_count) {
        qWarning("That's not supposed to happen...");
        return QVariant();
    }
 
    auto *instanceData = reinterpret_cast<const QQuick3DInstancing::InstanceTableEntry*>(m_instanceData.data()) + idx;
 
    switch (role) {
    case ColorRole:
        return instanceData->getColor();
    case PositionRole:
        return instanceData->getPosition();
    case RotationRole:
        return instanceData->getRotation();
    case ScaleRole:
        return instanceData->getScale();
    case CustomDataRole:
        return instanceData->instanceData;
    }
    return QVariant();
}
 
int InstanceModel::rowCount(const QModelIndex &) const
{
    ensureTable();
    return m_count;
}
 
void InstanceModel::setInstancing(QQuick3DInstancing *instancing)
{
    if (m_instancing == instancing)
        return;
    QObject::disconnect(m_tableConnection);
    m_instancing = instancing;
    m_tableConnection = QObject::connect(instancing, &QQuick3DInstancing::instanceTableChanged, this, &InstanceModel::reset);
    emit instancingChanged();
}
 
const QQuick3DInstancing::InstanceTableEntry *InstanceModel::instanceData(int index) const
{
    if (index >= m_count)
        return nullptr;
    return reinterpret_cast<const QQuick3DInstancing::InstanceTableEntry*>(m_instanceData.constData()) + index;
}
 
void InstanceModel::ensureTable() const
{
    auto *that = const_cast<InstanceModel*>(this);
    that->m_instanceData = m_instancing->instanceBuffer(&that->m_count);
}
 
void InstanceModel::reset()
{
    m_instanceData.clear();
}
 
InstanceRepeater::InstanceRepeater(QQuick3DNode *parent)
    : QQuick3DRepeater(parent)
{
}
 
QQuick3DInstancing *InstanceRepeater::instancing() const
{
    return m_model ? m_model->instancing() : nullptr;
}
 
void InstanceRepeater::setInstancing(QQuick3DInstancing *instancing)
{
    if (m_model && m_model->instancing() == instancing)
        return;
    if (!m_model)
        m_model = new InstanceModel(this);
    m_model->setInstancing(instancing);
    setModel(QVariant::fromValue(m_model));
    emit instancingChanged();
}
 
void InstanceRepeater::initDelegate(int index, QQuick3DNode *node)
{
    Q_ASSERT(m_model);
    auto *entry = m_model->instanceData(index);
    Q_ASSERT(entry);
    node->setPosition(entry->getPosition());
    node->setScale(entry->getScale());
    node->setRotation(entry->getRotation());
}
 
QT_END_NAMESPACE