Qt3D: Basic Shapes C++ Example
The Basic Shapes examples shows four basic shapes that Qt3D offers, a torus, a cylinder, a cube and a sphere. The example also shows how to embed a Qt3D scene into a widget and connect with other widgets.
As an example let's go through how to set up a torus mesh. First instantiate the QTorusMesh
, and then set the mesh specific parameters, that for torus are radius, minor radius and how many rings and slices.
m_torus = new Qt3D::QTorusMesh(); m_torus->setRadius(1.0f); m_torus->setMinorRadius(0.4f); m_torus->setRings(100); m_torus->setSlices(20);
The size and position of the torus can be adjusted with transform components. We create scale, translation and rotation components and add them into the QTransform
component.
Qt3D::QScaleTransform *torusScale = new Qt3D::QScaleTransform(); Qt3D::QTranslateTransform *torusTranslation = new Qt3D::QTranslateTransform(); Qt3D::QRotateTransform *torusRotation = new Qt3D::QRotateTransform(); Qt3D::QTransform *torusTransforms = new Qt3D::QTransform(); torusScale->setScale3D(QVector3D(2.0f, 2.0f, 2.0f)); torusTranslation->setTranslation(QVector3D(1.7f, 1.7f, 0.0f)); torusRotation->setAngleDeg(25.0f); torusRotation->setAxis(QVector3D(0, 1, 0)); torusTransforms->addTransform(torusRotation); torusTransforms->addTransform(torusTranslation); torusTransforms->addTransform(torusScale);
To change the diffuse color of the mesh we create a QPhongMaterial
and set its diffuse color.
Qt3D::QPhongMaterial *torusMaterial = new Qt3D::QPhongMaterial(); torusMaterial->setDiffuse(QColor(QRgb(0xbeb32b)));
The final step is to add the torus into an entity tree, and we do that by creating a QEntity
with parent entity and adding the previously created mesh, material and transform components into it.
m_torusEntity = new Qt3D::QEntity(m_rootEntity); m_torusEntity->addComponent(m_torus); m_torusEntity->addComponent(torusMaterial); m_torusEntity->addComponent(torusTransforms);
You can control the visibility of the entity by defining if it has parent or not, i.e. whether it is part of entity tree or not.
void SceneModifier::enableTorus(bool enabled) { m_torusEntity->setParent(enabled ? m_rootEntity : Q_NULLPTR); }
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