adding Qt3DCore::QEntity to q3dwindow dynamic(push a button to call slots in q3dwindow) cause transform odd.

[fisher103]

we create 3d object like this in qt5.8-windows:

//build a sphere
m_sphereMesh = new Qt3DExtras::QSphereMesh(m_pRootEntity);
m_mainSphereTransfrom = new Qt3DCore::QTransform(m_pRootEntity);
m_mainSphereMaterial = new Qt3DExtras::QPhongMaterial(m_pRootEntity);

//add component to sphere
Qt3DCore::QEntity *mainEntity = new Qt3DCore::QEntity(m_pRootEntity);
mainEntity->addComponent(m_sphereMesh);
mainEntity->addComponent(m_mainSphereMaterial);
mainEntity->addComponent(m_mainSphereTransfrom);

everything goes well when we do all these(build all spheres) in initial time. but when we add a button to add another sphere during running time, this new build sphere act unnormal for move command like (m_newSphereTransfrom->setTranslation(m_posNewPos);)

but the sphere display normal like pick, set color, or scale. only cannot move or rotate as initial-time build spheres.

===================================
follow are all the source code, when your press the closer button, you will find that new sphere would not moved, but the position return by transform is changed.
===================================

test3d.pro

QT += core gui 3dcore 3drender 3dextras

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = test3d
TEMPLATE = app

SOURCES += main.cpp
window3d.cpp
widget3d.cpp

HEADERS += window3d.h
widget3d.h

main.cpp

#include <QApplication>
#include "widget3d.h"

int main(int argc, char *argv[])
{

QApplication a(argc, argv);

Widget3D mainWidget;
mainWidget.show();

return a.exec();

}

window3d.h

#ifndef WINDOW3D_H
#define WINDOW3D_H

#include <Qt3DExtras/Qt3DWindow>
#include <Qt3DCore>
#include <Qt3DExtras/qphongmaterial.h>
#include <QPickEvent>
#include <QmouseEvent>
#include <Qt3DExtras/qcylindermesh.h>
#include <Qt3DExtras/qspheremesh.h>

class Window3D : public Qt3DExtras::Qt3DWindow
{
Q_OBJECT

public:

Window3D(QObject *parent = 0);
~Window3D();

void install3dEnvironment();

void createSphere();

public slots:

void createNewSphere();
void beCloser();

protected:

void addDirectLight(const QVector3D & pos, const QVector3D & dir, float intensity);

private:

Qt3DCore::QEntity *m_pRootEntity;
Qt3DCore::QEntity * m_sphere;
Qt3DExtras::QSphereMesh *m_mesh;
Qt3DExtras::QPhongMaterial *m_material;
Qt3DCore::QTransform *m_transfrom;

Qt3DCore::QEntity * m_newSphere;
Qt3DExtras::QSphereMesh *m_newMesh;
Qt3DExtras::QPhongMaterial *m_newMaterial;
Qt3DCore::QTransform *m_newTransfrom;

};

#endif // WINDOW3D_H

window3d.cpp

#include "window3d.h"
#include <Qt3DRender/QDirectionalLight>
#include <Qt3DRender/QCamera>
#include <Qt3DRender/QCameraLens>
#include <QOrbitCameraController>

Window3D::Window3D(QObject *parent):
m_pRootEntity(0),
m_sphere(0),
m_mesh(0),
m_material(0),
m_transfrom(0),
m_newSphere(0),
m_newMesh(0),
m_newMaterial(0),
m_newTransfrom(0)
{

m_pRootEntity = new Qt3DCore::QEntity();
setRootEntity(m_pRootEntity);
install3dEnvironment();
createSphere();

}

Window3D::~Window3D()
{

}

void Window3D::addDirectLight(const QVector3D & pos, const QVector3D & dir, float intensity)
{

Qt3DCore::QEntity *lightEntity = new Qt3DCore::QEntity(m_pRootEntity);
Qt3DRender::QDirectionalLight *light = new Qt3DRender::QDirectionalLight(m_pRootEntity);
light->setColor("white");
light->setIntensity(intensity);
light->setWorldDirection(dir);
Qt3DCore::QTransform *lightTransform = new Qt3DCore::QTransform(m_pRootEntity);
lightTransform->setTranslation(pos);
lightEntity->addComponent(light);
lightEntity->addComponent(lightTransform);

}

void Window3D::install3dEnvironment()
{

Qt3DRender::QCamera *cameraEntity = camera();
cameraEntity->lens()->setPerspectiveProjection(45.0f, 16.0f/9.0f, 0.1f, 100.0f);
cameraEntity->setPosition(QVector3D(0, 0, 20));
cameraEntity->setUpVector(QVector3D(0, 1, 0));
cameraEntity->setViewCenter(QVector3D(0, 0, 0));

addDirectLight(QVector3D(0, 0, 20), QVector3D(0, 0, -20), 1);

Qt3DExtras::QOrbitCameraController *camController = new Qt3DExtras::QOrbitCameraController(m_pRootEntity);
camController->setCamera(cameraEntity);

}

void Window3D::createSphere()
{

m_mesh = new Qt3DExtras::QSphereMesh(m_pRootEntity);
m_mesh->setRings(20);
m_mesh->setSlices(50);
m_mesh->setRadius(1);

m_transfrom = new Qt3DCore::QTransform(m_pRootEntity);
m_transfrom->setTranslation(QVector3D(-4,0,0));//set position

m_material = new Qt3DExtras::QPhongMaterial(m_pRootEntity);
m_material->setDiffuse("yellow");

m_sphere = new Qt3DCore::QEntity(m_pRootEntity);
m_sphere->addComponent(m_mesh);
m_sphere->addComponent(m_transfrom);
m_sphere->addComponent(m_material);

}

void Window3D::createNewSphere()
{

if (m_newSphere) return;
m_newMesh = new Qt3DExtras::QSphereMesh(m_pRootEntity);
m_newMesh->setRings(20);
m_newMesh->setSlices(50);
m_newMesh->setRadius(2);

m_newTransfrom = new Qt3DCore::QTransform(m_pRootEntity);
m_newTransfrom->setTranslation(QVector3D(4,0,0));//set position

m_newMaterial = new Qt3DExtras::QPhongMaterial(m_pRootEntity);
m_newMaterial->setDiffuse("green");

m_newSphere = new Qt3DCore::QEntity(m_pRootEntity);
m_newSphere->addComponent(m_newMesh);
m_newSphere->addComponent(m_newTransfrom);
m_newSphere->addComponent(m_newMaterial);

}

void Window3D::beCloser()
{

if (m_newSphere && m_sphere)
{
    m_transfrom->setTranslation(m_transfrom->translation()+QVector3D(0.1,0,0));
    m_newTransfrom->setTranslation(m_newTransfrom->translation() + QVector3D(-0.2, 0, 0));

    qDebug() << "new position:" << m_transfrom->translation() << m_newTransfrom->translation();
}

}

widget3d.h

#ifndef WIDGET3D_H
#define WIDGET3D_H

#include "window3d.h"
#include <QWidget>

class Widget3D : public QWidget
{
Q_OBJECT

public:

Widget3D(QObject *parent = 0);
~Widget3D();

private:

Window3D * m_wind3d;

};

#endif // WIDGET3D_H

widget3d.cpp

#include "widget3d.h"
#include <QPushButton>
#include <QHBoxLayout>

Widget3D::Widget3D(QObject *parent)
{

m_wind3d = new Window3D();
QWidget *view3d = QWidget::createWindowContainer(m_wind3d,this);
QSize screenSize = m_wind3d->screen()->size();
view3d->setMinimumSize(QSize(800, 500));
view3d->setMaximumSize(screenSize);

QHBoxLayout *hLayout = new QHBoxLayout(this);
QVBoxLayout *vLayout = new QVBoxLayout(this);

hLayout->addWidget(view3d);
hLayout->addLayout(vLayout);


QPushButton *addNewSphere = new QPushButton(this);
addNewSphere->setText(tr("New Sphere"));
connect(addNewSphere, SIGNAL(clicked()), m_wind3d, SLOT(createNewSphere()));
vLayout->addWidget(addNewSphere);

QPushButton *closerSphere = new QPushButton(this);
closerSphere->setText(tr("Be Closer"));
connect(closerSphere, SIGNAL(clicked()), m_wind3d, SLOT(beCloser()));
vLayout->addWidget(closerSphere);

this->setLayout(hLayout);

}

Widget3D::~Widget3D()
{

}

[m.sue]

Hi,

you may need to update() the Qt3DWindow explicitly.

-Michael.

[fisher103]

@m.sue I have tried Qt3DWindow::requestUpdate() after building sphere but it makes no diffrence. Also I call it in the timer, it keeps the same.
Any other advices?

[m.sue]

Hi,

please show how you create the second sphere, the "set translation" functions and how you call it.

-Michael.

[fisher103]

@m.sue the creation are the same. like this:
Qt3DCore::QTransform *localTransform = new Qt3DCore::QTransform(m_pRootEntity);
localTransform->setTranslation(pt3d);
m_vecSphereTransform.append(localTransform);

Qt3DExtras::QPhongMaterial *localMaterial = new Qt3DExtras::QPhongMaterial(m_pRootEntity);
localMaterial->setDiffuse(m_colorSphere);
m_vecSphereMaterial.append(localMaterial);

Qt3DCore::QEntity *localEntity = new Qt3DCore::QEntity(m_pRootEntity);

localEntity->addComponent(m_sphereMesh);
localEntity->addComponent(localMaterial);
localEntity->addComponent(localTransform);
m_vecSpheres.push_back(localEntity);

we save the pointer to QTransform into a vector and operate the position with the pointer in a timer.

[m.sue]

Hi,

I see two difference to how I do it:

• I do not set the root entity as parent to the mesh, material nor transform.
• I create a new mesh for each sphere.

Hope that helps.

-Michael.

[fisher103]

@m.sue I remove the root entity as parent to the mesh, material nor transform. it really works, thanks very much....
but I do not know why it acts like that way.