Qt 5.6 | Qt 3D | Qt 3D: Basic Shapes C++ Example

Qt 5.6.3 Reference Documentation

# Qt 3D: Basic Shapes C++ Example

Basic Shapes shows four basic shapes that Qt 3D offers: a torus, a cylinder, a cube, and a sphere. The example also shows how to embed a Qt 3D scene into a widget and connect with other widgets.

## Running the Example

To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.

## Setting Up a Torus Mesh

As an example, we go through how to set up a torus mesh. First, we instantiate the `QTorusMesh`, and then we set the mesh specific parameters, which for torus are radius, minor radius, and the number of rings and slices.

      m_torus = new Qt3DRender::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.

      Qt3DCore::QTransform *torusTransform = new Qt3DCore::QTransform();
      torusTransform->setScale(2.0f);
      torusTransform->setRotation(QQuaternion::fromAxisAndAngle(QVector3D(0.0f, 1.0f, 0.0f), 25.0f));
      torusTransform->setTranslation(QVector3D(4.0f, 4.0f, 0.0f));

To change the diffuse color of the mesh, we create a `QPhongMaterial` and set its diffuse color.

      Qt3DRender::QPhongMaterial *torusMaterial = new Qt3DRender::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 a parent entity and adding the previously created mesh, material, and transform components into it.

      m_torusEntity = new Qt3DCore::QEntity(m_rootEntity);
      m_torusEntity->addComponent(m_torus);
      m_torusEntity->addComponent(torusMaterial);
      m_torusEntity->addComponent(torusTransform);

We can control the visibility of the entity by defining whether it has a parent or not. That is, whether it is part of an entity tree or not.

      void SceneModifier::enableTorus(bool enabled)
      {
          m_torusEntity->setParent(enabled ? m_rootEntity : Q_NULLPTR);
      }

Files:

- basicshapes-cpp/scenemodifier.cpp
- basicshapes-cpp/scenemodifier.h
- basicshapes-cpp/main.cpp
- basicshapes-cpp/basicshapes-cpp.pro