Qt Quick 3D - Simple Skinning Example

 /****************************************************************************
 **
 ** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
 ** BSD License Usage
 ** Alternatively, you may use this file under the terms of the BSD license
 ** as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of The Qt Company Ltd nor the names of its
 **     contributors may be used to endorse or promote products derived
 **     from this software without specific prior written permission.
 **
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #ifndef SKINGEOMETRY_H
 #define SKINGEOMETRY_H

 #include <QtQuick3D/qquick3d.h>
 #include <QtQuick3D/qquick3dgeometry.h>

 #include <QVector3D>
 #include <QtCore/QList>

 class SkinGeometry : public QQuick3DGeometry
 {
     Q_OBJECT
     QML_NAMED_ELEMENT(SkinGeometry)
     Q_PROPERTY(QList<QVector3D> positions READ positions WRITE setPositions NOTIFY positionsChanged)
     Q_PROPERTY(QList<qint32> joints READ joints WRITE setJoints NOTIFY jointsChanged)
     Q_PROPERTY(QList<float> weights READ weights WRITE setWeights NOTIFY weightsChanged)
     Q_PROPERTY(QList<quint32> indexes READ indexes WRITE setIndexes NOTIFY indexesChanged)

 public:
     SkinGeometry(QQuick3DObject *parent = nullptr);

     QList<QVector3D> positions() const;
     QList<qint32> joints() const;
     QList<float> weights() const;
     QList<quint32> indexes() const;

 public Q_SLOTS:
     void setPositions(const QList<QVector3D> &positions);
     void setJoints(const QList<qint32> &joints);
     void setWeights(const QList<float> &weights);
     void setIndexes(const QList<quint32> &indexes);

 Q_SIGNALS:
     void positionsChanged();
     void jointsChanged();
     void weightsChanged();
     void indexesChanged();

 protected:
     QSSGRenderGraphObject *updateSpatialNode(QSSGRenderGraphObject *node) override;

 private:
     QList<QVector3D> m_positions;
     QList<qint32> m_joints;
     QList<float> m_weights;
     QList<quint32> m_indexes;

     bool m_vertexDirty = false;
     bool m_indexDirty = false;

     QByteArray m_vertexBuffer;
     QByteArray m_indexBuffer;
 };

 #endif // SKINGEOMETRY_H