- Qt 5.5
- Qt3D Module
- Qt3D: Big Scene C++ Example
- main.cpp Example File
- Qt 5.5.1 Reference Documentation

# main.cpp Example File

bigscene-cpp/main.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
    ** Contact: http://www.qt-project.org/legal
    **
    ** This file is part of the Qt3D module of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:LGPL3$
    ** Commercial License Usage
    ** Licensees holding valid commercial Qt licenses may use this file in
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    ** information use the contact form at http://www.qt.io/contact-us.
    **
    ** GNU Lesser General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU Lesser
    ** General Public License version 3 as published by the Free Software
    ** Foundation and appearing in the file LICENSE.LGPLv3 included in the
    ** packaging of this file. Please review the following information to
    ** ensure the GNU Lesser General Public License version 3 requirements
    ** will be met: https://www.gnu.org/licenses/lgpl.html.
    **
    ** GNU General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU
    ** General Public License version 2.0 or later as published by the Free
    ** Software Foundation and appearing in the file LICENSE.GPL included in
    ** the packaging of this file. Please review the following information to
    ** ensure the GNU General Public License version 2.0 requirements will be
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    #include <QGuiApplication>
    #include <window.h>

    #include <QPropertyAnimation>
    #include <QUrl>
    #include <QTimer>
    #include <Qt3DCore/QEntity>
    #include <Qt3DCore/QCamera>
    #include <Qt3DCore/QTransform>
    #include <Qt3DCore/QTranslateTransform>
    #include <Qt3DCore/QRotateTransform>
    #include <Qt3DCore/QScaleTransform>
    #include <Qt3DCore/qaspectengine.h>
    #include <Qt3DInput/QInputAspect>
    #include <Qt3DRenderer/QParameter>
    #include <Qt3DRenderer/QFrameGraph>
    #include <Qt3DRenderer/QCylinderMesh>
    #include <Qt3DRenderer/QRenderAspect>
    #include <Qt3DRenderer/QCameraSelector>
    #include <Qt3DRenderer/QPhongMaterial>
    #include <Qt3DRenderer/QForwardRenderer>
    #include <qmath.h>

    using namespace Qt3D;

    int main(int ac, char **av)
    {
        QGuiApplication app(ac, av);

        Window view;
        Qt3D::QAspectEngine engine;
        engine.registerAspect(new Qt3D::QRenderAspect());
        Qt3D::QInputAspect *input = new Qt3D::QInputAspect;
        engine.registerAspect(input);
        engine.initialize();
        QVariantMap data;
        data.insert(QStringLiteral("surface"), QVariant::fromValue(static_cast<QSurface *>(&view)));
        data.insert(QStringLiteral("eventSource"), QVariant::fromValue(&view));
        engine.setData(data);
        QEntity *root = new QEntity();

        // Camera
        QCamera *cameraEntity = new QCamera(root);
        cameraEntity->setObjectName(QStringLiteral("cameraEntity"));
        cameraEntity->lens()->setPerspectiveProjection(45.0f, 16.0f/9.0f, 0.1f, 1000.0f);
        cameraEntity->setPosition(QVector3D(0, -250.0f, -50.0f));
        cameraEntity->setUpVector(QVector3D(0, 1, 0));
        cameraEntity->setViewCenter(QVector3D(0, 0, 0));
        input->setCamera(cameraEntity);

        // FrameGraph
        QFrameGraph *frameGraph = new QFrameGraph();
        QForwardRenderer *forwardRenderer = new QForwardRenderer();
        forwardRenderer->setCamera(cameraEntity);
        forwardRenderer->setClearColor(Qt::black);
        frameGraph->setActiveFrameGraph(forwardRenderer);
        root->addComponent(frameGraph);

        const float radius = 100.0f;
        const int max = 1000;
        const float det = 1.0f / max;
        // Scene
        for (int i = 0; i < max; i++) {
            QEntity *e = new QEntity();
            Qt3D::QTransform *transform = new Qt3D::QTransform();
            QTranslateTransform *translation = new QTranslateTransform();
            QRotateTransform *rotateX = new QRotateTransform();
            QRotateTransform *rotateZ = new QRotateTransform();
            QCylinderMesh *mesh = new QCylinderMesh();
            QPhongMaterial *material = new QPhongMaterial();
            mesh->setRings(50.0f);
            mesh->setSlices(30.0f);
            mesh->setRadius(2.5f);
            mesh->setLength(5.0f);

            const float angle = M_PI * 2.0f * i * det * 10.;

            material->setDiffuse(QColor(qFabs(qCos(angle)) * 255, 204, 75));
            material->setAmbient(Qt::black);
            material->setSpecular(Qt::white);
            material->setShininess(150.0f);

            translation->setTranslation(QVector3D(radius * qCos(angle), 200.* i * det, radius * qSin(angle)));
            rotateX->setAxis(QVector3D(1.0f, 0.0f, 0.0f));
            rotateZ->setAxis(QVector3D(0.0f, 0.0f, 1.0f));
            rotateX->setAngleDeg(30.0f * i);
            rotateZ->setAngleDeg(45.0f * i);

            QPropertyAnimation *animX = new QPropertyAnimation(rotateX, QByteArrayLiteral("angle"));
            animX->setDuration(2400 * i);
            animX->setStartValue(QVariant::fromValue(i * 30.0f));
            animX->setEndValue(QVariant::fromValue((i + 1) * 390.0f));
            animX->setLoopCount(-1);
            animX->start();

            QPropertyAnimation *animZ = new QPropertyAnimation(rotateZ, QByteArrayLiteral("angle"));
            animZ->setDuration(2400 * i);
            animZ->setStartValue(QVariant::fromValue(i * 20.0f));
            animZ->setEndValue(QVariant::fromValue((i + 1) * 380.0f));
            animZ->setLoopCount(-1);
            animZ->start();

            transform->addTransform(rotateX);
            transform->addTransform(rotateZ);
            transform->addTransform(translation);
            e->addComponent(transform);
            e->addComponent(mesh);
            e->addComponent(material);
            e->setParent(root);
        }

        engine.setRootEntity(root);
        view.show();

        if (app.arguments().contains(("--bench")))
            QTimer::singleShot(25 * 1000, &app, &QCoreApplication::quit);

        return app.exec();
    }