Rotating an object in 3D quaternions

Ruslan_N

I'm writing a program with 3D qt 5.9, I need to write a function that will create a line (cylinder) from point A (x, y, z) to point B (x, y, z), I could create a cylinder, line (The cylinder is created parallel to the Y axis), set the length and specify the initial coordinates but do not get it to the desired point, I found that it needs to do a U-turn using quaternions but I did not understand how to correctly apply it, can anyone know how in qt using Quaternions to deploy the object to the desired point.

#include <QGuiApplication>

#include <Qt3DCore/QEntity>
#include <Qt3DRender/QCamera>
#include <Qt3DRender/QCameraLens>
#include <Qt3DCore/QTransform>
#include <Qt3DCore/QAspectEngine>

#include <Qt3DInput/QInputAspect>

#include <Qt3DRender/QRenderAspect>
#include <Qt3DExtras/QForwardRenderer>
#include <Qt3DExtras/QPhongMaterial>
#include <Qt3DExtras/QCylinderMesh>
#include <Qt3DExtras/QSphereMesh>
#include <Qt3DExtras/QTorusMesh>

#include <QPropertyAnimation>

#include "qt3dwindow.h"
#include "orbittransformcontroller.h"
#include "qorbitcameracontroller.h"
#include <QDebug>
#include <math.h>

//Перевод из радиан в градусы
double Deg_Rad(double grad)
{
return (3.14/180)*grad;
}

//Перевод из радиан в градусы
double Rad_Deg(double radian)
{
return (180/3.14)*radian;
}
//создает сцену и оси
Qt3DCore::QEntity *createScene()
{
// Root entity
Qt3DCore::QEntity *rootEntity = new Qt3DCore::QEntity;

Qt3DCore::QEntity *xaxis = new Qt3DCore::QEntity(rootEntity);
Qt3DCore::QEntity *yaxis = new Qt3DCore::QEntity(rootEntity);
Qt3DCore::QEntity *zaxis = new Qt3DCore::QEntity(rootEntity);


Qt3DExtras::QCylinderMesh* cylinderMesh = new Qt3DExtras::QCylinderMesh;
cylinderMesh->setRadius(0.2);
cylinderMesh->setLength(90);
cylinderMesh->setRings(100);
cylinderMesh->setSlices(70);

Qt3DExtras::QPhongMaterial* blueMaterial = new Qt3DExtras::QPhongMaterial;
blueMaterial->setSpecular(Qt::white);
blueMaterial->setShininess(10);
blueMaterial->setAmbient(Qt::blue);


Qt3DCore::QTransform* xTransform = new Qt3DCore::QTransform();
xTransform->setTranslation(QVector3D(45,0,0));
xTransform->setRotation(QQuaternion::fromAxisAndAngle(QVector3D(0,0,1),90));
Qt3DCore::QTransform* yTransform = new Qt3DCore::QTransform();
yTransform->setTranslation(QVector3D(0,45,0));
Qt3DCore::QTransform* zTransform = new Qt3DCore::QTransform();
zTransform->setTranslation(QVector3D(0,0,45));
zTransform->setRotation(QQuaternion::fromAxisAndAngle(QVector3D(1,0,0),90));

Qt3DExtras::QPhongMaterial*  redMaterial = new Qt3DExtras::QPhongMaterial;
redMaterial->setSpecular(Qt::white);
redMaterial->setShininess(5);
redMaterial->setAmbient(Qt::red);


Qt3DExtras::QPhongMaterial* greenMaterial = new Qt3DExtras::QPhongMaterial;
greenMaterial->setSpecular(Qt::white);
greenMaterial->setShininess(10);
greenMaterial->setAmbient(Qt::green);

Qt3DExtras::QPhongMaterial* blueMateria1l = new Qt3DExtras::QPhongMaterial;
blueMateria1l->setSpecular(Qt::white);
blueMateria1l->setShininess(10);
blueMateria1l->setAmbient(Qt::blue);

xaxis->addComponent(cylinderMesh);
xaxis->addComponent(redMaterial);
xaxis->addComponent(xTransform);
yaxis->addComponent(cylinderMesh);
yaxis->addComponent(greenMaterial);
yaxis->addComponent(yTransform);
zaxis->addComponent(cylinderMesh);
zaxis->addComponent(blueMaterial);
zaxis->addComponent(zTransform);

return rootEntity;

}
//Функция создания линни
void creatline(Qt3DCore::QEntity *scene, double x1, double y1,double z1,double x2,double y2 , double z2){

// Материал
Qt3DExtras::QPhongMaterial* redMaterial = new Qt3DExtras::QPhongMaterial;
redMaterial->setSpecular(Qt::white);
redMaterial->setShininess(5);
redMaterial->setAmbient(Qt::red);

Qt3DExtras::QCylinderMesh* cylinderMesh = new Qt3DExtras::QCylinderMesh;
cylinderMesh->setRadius(0.2);
cylinderMesh->setLength(90);
cylinderMesh->setRings(100);
cylinderMesh->setSlices(70);

//  шар для наглядности вращения 
// Material
Qt3DRender::QMaterial *material = new Qt3DExtras::QPhongMaterial(scene);

// Sphere
Qt3DCore::QEntity *sphereEntity = new Qt3DCore::QEntity(scene);
Qt3DExtras::QSphereMesh *sphereMesh = new Qt3DExtras::QSphereMesh;
sphereMesh->setRadius(1);

Qt3DCore::QTransform *sphereTransform = new Qt3DCore::QTransform;
OrbitTransformController *controller = new OrbitTransformController(sphereTransform);
controller->setTarget(sphereTransform);
sphereTransform->setTranslation(QVector3D(x2,y2,z2));

sphereEntity->addComponent(sphereMesh);
sphereEntity->addComponent(sphereTransform);
sphereEntity->addComponent(material);
//


Qt3DCore::QEntity *test = new Qt3DCore::QEntity(scene);
test->addComponent(redMaterial);
test->addComponent(cylinderMesh);
Qt3DCore::QTransform* Transform = new Qt3DCore::QTransform();
// Установка координат 
Transform->setTranslation(QVector3D(x1,y1,z1));
//Вращение линнии 
Transform->setRotation(QQuaternion::rotationTo(QVector3D(x1,y1,z1),QVector3D(x2,y2,y2)));

qDebug()<<Transform->rotationX();
qDebug()<<Transform->rotationY();
qDebug()<<Transform->rotationZ();


test->addComponent(Transform);

}

int main(int argc, char* argv[])
{
QGuiApplication app(argc, argv);
Qt3DExtras::Qt3DWindow view;

Qt3DCore::QEntity *scene = createScene();

//функция создания линии 
creatline(scene,0,0,0,0,0,20);


// Camera
Qt3DRender::QCamera *camera = view.camera();
camera->lens()->setPerspectiveProjection(45.0f, 16.0f/9.0f, 0.1f, 1000.0f);
camera->setPosition(QVector3D(0, 0, 40.0f));
camera->setViewCenter(QVector3D(0, 0, 0));

// For camera controls
Qt3DExtras::QOrbitCameraController *camController = new Qt3DExtras::QOrbitCameraController(scene);
camController->setLinearSpeed( 50.0f );
camController->setLookSpeed( 180.0f );
camController->setCamera(camera);

view.setRootEntity(scene);
view.show();

return app.exec();

}

Vultor

I use this code to connect cilinders to spheres:

QListQt3DExtras::QCylinderMesh* cylinderListMesh;
QListQt3DCore::QTransform* cylinderListTransform;
QListQt3DCore::QTransform* sphereListTransform;

void ShowMolecule::atomsConnections(int atomA, int atomB, int bondI)
{
QVector3D rAB = sphereListTransform[atomA]->translation()-sphereListTransform[atomB]->translation();
cylinderListTransform[bondI]->setRotation(QQuaternion::rotationTo(QVector3D(0,1,0), rAB));
cylinderListMesh[bondI]->setLength(rAB.length());
cylinderListTransform[bondI]->setTranslation(QVector3D(
sphereListTransform[atomB]->translation()+rAB/2.0e0));
}