I have the following code ``` void SceneWalker::walkEntity(Qt3DCore::QEntity *e, int depth) { Qt3DCore::QNodeVector nodes = e->childNodes(); for (int i = 0; i < nodes.count(); ++i) { Qt3DCore::QNode *node = nodes[i]; Qt3DCore::QEntity *entity = qobject_cast<Qt3DCore::QEntity *>(node); if (entity) { QString indent; indent.fill(' ', depth * 2); qDebug().noquote() << indent << "Entity:" << entity << "Components:" << entity->components();
{ // Question about BoundingVolume qDebug() << "BoundingVolume: " << entity->objectName(); const QList<Qt3DRender::QGeometryRenderer *> myQGeometryRenderer = entity->componentsOfType<Qt3DRender::QGeometryRenderer>(); if (!myQGeometryRenderer.isEmpty()) { Qt3DRender::QGeometryRenderer *gr = myQGeometryRenderer[0]; QVector3D minPoint = gr->implicitMinPoint(); QVector3D maxPoint = gr->implicitMaxPoint(); qDebug() << "minPoint: " << minPoint; qDebug() << "maxPoint: " << maxPoint; } } walkEntity(entity, depth + 1); } } } ``` But I got the (0,0,0) for both the min/max point ``` Status changed: Qt3DRender::QSceneLoader::Loading Status changed: Qt3DRender::QSceneLoader::Ready Entity: Qt3DCore::QEntity(0x7f65dc004660, name = untitled.obj) Components: QList(Qt3DCore::QTransform(0x7f65dc04c590)) Entity: Qt3DCore::QEntity(0x7f65dc019220, name = Suzanne) Components: QList(Qt3DExtras::QPhongMaterial(0x7f65dc01bf30, name = DefaultMaterial), Qt3DRender::QGeometryRenderer(0x7f65dc00c4d0), Qt3DCore::QTransform(0x7f65dc045800)) BoundingVolume: "Suzanne" minPoint: QVector3D(0, 0, 0) maxPoint: QVector3D(0, 0, 0) BoundingVolume: "untitled.obj" ``` I am using Qt 6.2.2 on Ubuntu Cheers On Wed, 3 Aug 2022 at 01:25, Mike Krus <mike.k...@kdab.com> wrote: > Hi > > once the scene is loaded (ie, the status is Ready, keeping in mind loading > is asynchronous), you can use > QSceneLoader::entity() to get a loaded entity by name, and then > QEntity::componentsOfType() to get the component. > Loaded entities are children of the entity that the QSceneLoader component > was assigned to, and components and > entities are all QObjects so you can use the normal tree traversal > techniques that work with any QObject to find > objects by type or name. > > > Mike > > > On 3 Aug 2022, at 00:14, Nicholas Yue <yue.nicho...@gmail.com> wrote: > > > > Thank you Mike. > > > > Follow up question: > > > > Given a > > > > ``` > > Qt3DRender::QSceneLoader *sceneLoader; > > ``` > > > > How do we get at this QGeometryRenderer object to be able to call the > impliciteMinPoint (), impliciteMaxPoint () properties ? > > > > Cheers > > > > On Tue, 2 Aug 2022 at 05:56, Mike Krus <mike.k...@kdab.com> wrote: > > Hi > > > > if you are using Qt6, then yes. > > > > For a specific object, QGeometryRenderer derives from QBoundingVolume > which has impliciteMinPoint and impliciteMaxPoint properties. > > > > If you’re interested in the bounding volume of a portion of the scene > graph, all a QBoundingVolume component at the root and the > > same properties will be updated. > > > > In Qt5, the QGeometry node associated with each render has similar > min/max properties (note that they only valid if the mesh uses all the > geometry). > > > > Hope this helps, > > > > Mike > > > > > > > On 1 Aug 2022, at 16:05, Nicholas Yue <yue.nicho...@gmail.com> wrote: > > > > > > Hi, > > > > > > I am diving into the geometry scene via QSceneLoader. > > > > > > Using the following code as a starting point, I wish to place the > camera such that it automatically accommodates scenes of different sizes. > > > > > > One way I am thinking of doing is to base on the scene geometry > bounding box. > > > > > > Is there a method or API which I can call to query the entire scene > geometry bounding box ? Or do I have to walk the entire scene to build that > up by querying the bounding box for every geometry in the scene ? > > > > > > Any sample code I can view to get me going ? > > > > > > ``` > > > > /**************************************************************************** > > > ** > > > ** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB). > > > ** Contact: https://www.qt.io/licensing/ > > > ** > > > ** This file is part of the Qt3D module 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." > > > ** > > > ** $QT_END_LICENSE$ > > > ** > > > > ****************************************************************************/ > > > > > > #include <QFileDialog> > > > #include <QApplication> > > > > > > #include <Qt3DRender/QCamera> > > > #include <Qt3DCore/QEntity> > > > #include <Qt3DCore/QAspectEngine> > > > #include <Qt3DInput/QInputAspect> > > > #include <Qt3DRender/QSceneLoader> > > > #include <Qt3DRender/QRenderAspect> > > > #include <Qt3DExtras/QForwardRenderer> > > > #include <Qt3DExtras/qt3dwindow.h> > > > // #include <Qt3DExtras/qfirstpersoncameracontroller.h> > > > #include "MyCameraController.h" > > > #include "TrackballCameraController.h" > > > > > > class SceneWalker : public QObject > > > { > > > public: > > > SceneWalker(Qt3DRender::QSceneLoader *loader) : m_loader(loader) { > } > > > > > > void onStatusChanged(); > > > > > > private: > > > void walkEntity(Qt3DCore::QEntity *e, int depth = 0); > > > > > > Qt3DRender::QSceneLoader *m_loader; > > > }; > > > > > > void SceneWalker::onStatusChanged() > > > { > > > qDebug() << "Status changed:" << m_loader->status(); > > > if (m_loader->status() != Qt3DRender::QSceneLoader::Ready) > > > return; > > > > > > // The QSceneLoader instance is a component of an entity. The > loaded scene > > > // tree is added under this entity. > > > QVector<Qt3DCore::QEntity *> entities = m_loader->entities(); > > > > > > // Technically there could be multiple entities referencing the > scene loader > > > // but sharing is discouraged, and in our case there will be one > anyhow. > > > if (entities.isEmpty()) > > > return; > > > Qt3DCore::QEntity *root = entities[0]; > > > // Print the tree. > > > walkEntity(root); > > > > > > // To access a given node (like a named mesh in the scene), use > QObject::findChild(). > > > // The scene structure and names always depend on the asset. > > > Qt3DCore::QEntity *e = root->findChild<Qt3DCore::QEntity > *>(QStringLiteral("PlanePropeller_mesh")); // toyplane.obj > > > if (e) > > > qDebug() << "Found propeller node" << e << "with components" > << e->components(); > > > } > > > > > > void SceneWalker::walkEntity(Qt3DCore::QEntity *e, int depth) > > > { > > > Qt3DCore::QNodeVector nodes = e->childNodes(); > > > for (int i = 0; i < nodes.count(); ++i) { > > > Qt3DCore::QNode *node = nodes[i]; > > > Qt3DCore::QEntity *entity = qobject_cast<Qt3DCore::QEntity > *>(node); > > > if (entity) { > > > QString indent; > > > indent.fill(' ', depth * 2); > > > qDebug().noquote() << indent << "Entity:" << entity << > "Components:" << entity->components(); > > > walkEntity(entity, depth + 1); > > > } > > > } > > > } > > > > > > int main(int ac, char **av) > > > { > > > QApplication app(ac, av); > > > Qt3DExtras::Qt3DWindow view; > > > view.defaultFrameGraph()->setClearColor(Qt::black); > > > > > > // Root entity > > > Qt3DCore::QEntity *sceneRoot = new Qt3DCore::QEntity(); > > > > > > // Scene Camera > > > Qt3DRender::QCamera *camera = view.camera(); > > > > camera->setProjectionType(Qt3DRender::QCameraLens::PerspectiveProjection); > > > camera->setViewCenter(QVector3D(0.0f, 3.5f, 0.0f)); > > > camera->setPosition(QVector3D(0.0f, 3.5f, 25.0f)); > > > camera->setNearPlane(0.001f); > > > camera->setFarPlane(10000.0f); > > > > > > // For camera controls > > > // Qt3DExtras::QFirstPersonCameraController *camController = new > Qt3DExtras::QFirstPersonCameraController(sceneRoot); > > > TrackballCameraController *camController = new > TrackballCameraController(sceneRoot); > > > camController->setWindowSize(QSize(view.width(),view.height())); > // > https://github.com/cjmdaixi/Qt3DTrackball/issues/1#issuecomment-544183228 > > > camController->setCamera(camera); > > > > > > // Scene loader > > > Qt3DCore::QEntity *sceneLoaderEntity = new > Qt3DCore::QEntity(sceneRoot); > > > Qt3DRender::QSceneLoader *sceneLoader = new > Qt3DRender::QSceneLoader(sceneLoaderEntity); > > > SceneWalker sceneWalker(sceneLoader); > > > QObject::connect(sceneLoader, > &Qt3DRender::QSceneLoader::statusChanged, &sceneWalker, > &SceneWalker::onStatusChanged); > > > sceneLoaderEntity->addComponent(sceneLoader); > > > > > > QStringList args = QCoreApplication::arguments(); > > > QUrl sourceFileName; > > > if (args.count() <= 1) { > > > QWidget *container = new QWidget(); > > > QFileDialog dialog; > > > dialog.setFileMode(QFileDialog::AnyFile); > > > sourceFileName = dialog.getOpenFileUrl(container, > QStringLiteral("Open a scene file")); > > > } else { > > > sourceFileName = QUrl::fromLocalFile(args[1]); > > > } > > > > > > if (sourceFileName.isEmpty()) > > > return 0; > > > > > > sceneLoader->setSource(sourceFileName); > > > > > > view.setRootEntity(sceneRoot); > > > view.show(); > > > > > > return app.exec(); > > > } > > > ``` > > > > > > Cheers > > > -- > > > Nicholas Yue > > > https://www.linkedin.com/in/nicholasyue/ > > > _______________________________________________ > > > Interest mailing list > > > Interest@qt-project.org > > > https://lists.qt-project.org/listinfo/interest > > > > — > > Mike Krus | mike.k...@kdab.com | Senior Software Engineer & Teamlead > > KDAB (UK) Ltd., a KDAB Group company > > Tel: UK Office +44 1625 809908 Mobile +44 7833 491941 > > KDAB - The Qt Experts, C++, OpenGL Experts > > > > > > > > > > -- > > Nicholas Yue > > https://www.linkedin.com/in/nicholasyue/ > > — > Mike Krus | mike.k...@kdab.com | Senior Software Engineer & Teamlead > KDAB (UK) Ltd., a KDAB Group company > Tel: UK Office +44 1625 809908 Mobile +44 7833 491941 > KDAB - The Qt Experts, C++, OpenGL Experts > > > -- Nicholas Yue https://www.linkedin.com/in/nicholasyue/
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