Integration fo Qt3D C++ back-end with QML front-end?

Alain38 0

Hi,
I have a full C++ application encapsulating a class derived form Qt3DWindow. This class makes a lot of stuff. Now I have to integrate this class in an application that is written with QML. So, I have a full front-end in QML containing one item for my view/window. The problem is that I do not arrive to make the migration.

I tried to extract the root entity, add it a camera and a ForwardRenderer, as found in a QML example. But nothing is displayed. In fact even the "clear" operation is not performed. I have seen that the renderer as no surface. So I explicitely set the main window as surface. No change. I tried to put my entity in a Scene3D. No change. I tried to encapsulate all my stuff in a QWidget. But QML does not accept QWidget, according to what I found on Internet.

So, I am a little bit desperate. If someone has the solution.
Thanks.

Alain38 0

OK,
Finally we found the solution. The tip is to create a Scene3D in the qml file. And to create the camera and ForwaqrdRenderer in the QML too (and not in the C++).

    Scene3D {
        id: scene3D
        anchors.fill: parent
        anchors.margins: 10
        focus: true

        Root3DEntity {
            id : root3DEntity
            renderSettings : RenderSettings {
                id : renderSettings
                pickingSettings.pickMethod : pickingSettings.PrimitivePicking

                activeFrameGraph: ForwardRenderer {
                    id: renderer
                    clearColor: "#4d4d4f"

                    camera: Camera {
                        id: camera
                        projectionType: CameraLens.PerspectiveProjection
                        fieldOfView: 45
                        nearPlane: 0.1
                        farPlane: 1000.0
                        position: Qt.vector3d(0.0, 0.0, 2.0)
                        upVector: Qt.vector3d(0.0, 1.0, 0.0)
                        viewCenter: Qt.vector3d(0.0, 0.0, 0.0)
                    }
                }
            }
        }
    }