Qt5 : QOpenGLContext::swapBuffers() called with non-exposed window, behavior is undefined
Unsolved
General and Desktop
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I have the following code from KDAB via the qt3d repository. When I compile and run it (Ubuntu 18.04), I get the swapBuffers() message. What do I need to do in the code to silence the message ?
/**************************************************************************** ** ** 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> 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); 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(); }
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The error is caused by painting into a non exposed window.
In your case the painting starts before the scene is exposed, maybe because the scene file is large and/or the system is slow. -
Possible but I have a nVidia GPU display and I am loading a simple OBJ (the Suzanne mesh from Blender)
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Do you have minimal example to reproduce the problem? You may have found a bug.
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@Axel-Spoerl the code I attached in the first message triggered the problem so you may try with that.