Send further pick events to initial object picker

Once an object picker receives a press event, all further
events will be sent to it until the mouse is released.
This enables interactive with objects that move behind
other pickable objects. In that case, the pick event
will be sent to the active object picker.

This behavior is disabled if all pick events are
requested (which works as before).

Included an example where a cylinder is dragged to
control the radius of a cone (like a slider) and
moves behind another pickable object (while remaining
interactive).

Task-number: QTBUG-55495
Change-Id: I4e3b8466d01ca1d08ef48c1fa6f6abd5b5404980
Reviewed-by: Kevin Ottens <kevin.ottens@kdab.com>

10 files changed, 503 insertions, 7 deletions

diff --git a/src/render/jobs/pickboundingvolumejob.cpp b/src/render/jobs/pickboundingvolumejob.cpp
index 8af99dfc3..938487322 100644
--- a/src/render/jobs/pickboundingvolumejob.cpp
+++ b/src/render/jobs/pickboundingvolumejob.cpp
@@ -260,7 +260,7 @@ bool PickBoundingVolumeJob::runHelper()
             }
 
             // Dispatch events based on hit results
-            dispatchPickEvents(event, sphereHits, eventButton, eventButtons, eventModifiers, trianglePickingRequested);
+            dispatchPickEvents(event, sphereHits, eventButton, eventButtons, eventModifiers, trianglePickingRequested, allHitsRequested);
         }
     }
 
@@ -293,7 +293,8 @@ void PickBoundingVolumeJob::dispatchPickEvents(const QMouseEvent &event,
                                                QPickEvent::Buttons eventButton,
                                                int eventButtons,
                                                int eventModifiers,
-                                               bool trianglePickingRequested)
+                                               bool trianglePickingRequested,
+                                               bool allHitsRequested)
 {
     ObjectPicker *lastCurrentPicker = m_manager->objectPickerManager()->data(m_currentPicker);
     // If we have hits
@@ -303,9 +304,6 @@ void PickBoundingVolumeJob::dispatchPickEvents(const QMouseEvent &event,
         // How do we differentiate betwnee an Entity with no GeometryRenderer and one with one, both having
         // an ObjectPicker component when it comes
 
-        // We want to gather hits against triangles
-        // build a triangle based bounding volume
-
         for (const QCollisionQueryResult::Hit &hit : qAsConst(sphereHits)) {
             Entity *entity = m_manager->renderNodesManager()->lookupResource(hit.m_entityId);
             HObjectPicker objectPickerHandle = entity->componentHandle<ObjectPicker, 16>();
@@ -320,6 +318,14 @@ void PickBoundingVolumeJob::dispatchPickEvents(const QMouseEvent &event,
 
             ObjectPicker *objectPicker = m_manager->objectPickerManager()->data(objectPickerHandle);
             if (objectPicker != nullptr && objectPicker->isEnabled()) {
+
+                if (lastCurrentPicker && !allHitsRequested) {
+                    // if there is a current picker, it will "grab" all events until released.
+                    // Clients should test that entity is what they expect (or only use
+                    // world coordinates)
+                    objectPicker = lastCurrentPicker;
+                }
+
                 // Send the corresponding event
                 QVector3D localIntersection = hit.m_intersection;
                 if (entity && entity->worldTransform())
diff --git a/src/render/jobs/pickboundingvolumejob_p.h b/src/render/jobs/pickboundingvolumejob_p.h
index 8d0d01f48..ccdba73a8 100644
--- a/src/render/jobs/pickboundingvolumejob_p.h
+++ b/src/render/jobs/pickboundingvolumejob_p.h
@@ -105,8 +105,8 @@ protected:
     void run() Q_DECL_FINAL;
     void dispatchPickEvents(const QMouseEvent &event, const PickingUtils::CollisionVisitor::HitList &sphereHits,
                             QPickEvent::Buttons eventButton,
-                            int eventButtons,
-                            int eventModifiers, bool trianglePickingRequested);
+                            int eventButtons, int eventModifiers,
+                            bool trianglePickingRequested, bool allHitsRequested);
 
 private:
     NodeManagers *m_manager;
diff --git a/tests/auto/render/pickboundingvolumejob/pickboundingvolumejob.qrc b/tests/auto/render/pickboundingvolumejob/pickboundingvolumejob.qrc
index e08d05187..fbd6a0a05 100644
--- a/tests/auto/render/pickboundingvolumejob/pickboundingvolumejob.qrc
+++ b/tests/auto/render/pickboundingvolumejob/pickboundingvolumejob.qrc
@@ -6,5 +6,6 @@
         <file>testscene_improperframegraph.qml</file>
         <file>testscene_dragenabledhoverenabled.qml</file>
         <file>testscene_pickersdisabled.qml</file>
+        <file>testscene_dragenabledoverlapping.qml</file>
     </qresource>
 </RCC>
diff --git a/tests/auto/render/pickboundingvolumejob/testscene_dragenabledoverlapping.qml b/tests/auto/render/pickboundingvolumejob/testscene_dragenabledoverlapping.qml
new file mode 100644
index 000000000..4280b8555
--- /dev/null
+++ b/tests/auto/render/pickboundingvolumejob/testscene_dragenabledoverlapping.qml
@@ -0,0 +1,134 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import Qt3D.Core 2.0
+import Qt3D.Render 2.0
+import Qt3D.Extras 2.0
+import QtQuick.Window 2.0
+
+Entity {
+    id: sceneRoot
+
+    Window {
+        id: win
+        width: 600
+        height: 600
+        visible: true
+    }
+
+    Camera {
+        id: camera
+        projectionType: CameraLens.PerspectiveProjection
+        fieldOfView: 45
+        nearPlane : 0.1
+        farPlane : 1000.0
+        position: Qt.vector3d( 0.0, 0.0, -40.0 )
+        upVector: Qt.vector3d( 0.0, 1.0, 0.0 )
+        viewCenter: Qt.vector3d( 0.0, 0.0, 0.0 )
+    }
+
+    components: [
+        RenderSettings {
+            Viewport {
+                normalizedRect: Qt.rect(0.0, 0.0, 1.0, 1.0)
+
+                RenderSurfaceSelector {
+
+                    surface: win
+
+                    ClearBuffers {
+                        buffers : ClearBuffers.ColorDepthBuffer
+                        NoDraw {}
+                    }
+
+                    CameraSelector {
+                        camera: camera
+                    }
+                }
+            }
+        }
+    ]
+
+    CuboidMesh { id: cubeMesh }
+    PhongMaterial { id: material }
+
+    // Entity 1
+    Entity {
+        property ObjectPicker picker: ObjectPicker {
+            id: picker1
+            objectName: "Picker1"
+            dragEnabled: true
+        }
+
+        property Transform transform: Transform {
+            translation: Qt.vector3d(-.5, 0, 0)
+            scale: 2.0
+        }
+
+        components: [cubeMesh, material, picker1, transform]
+    }
+
+    // Entity 2
+    Entity {
+        property ObjectPicker picker: ObjectPicker {
+            id: picker2
+            objectName: "Picker2"
+            dragEnabled: true
+            hoverEnabled: true
+        }
+
+        property Transform transform: Transform {
+            translation: Qt.vector3d(1.5, 0, 0)
+            scale: 2.5
+        }
+
+        components: [cubeMesh, material, picker2, transform]
+    }
+}
diff --git a/tests/auto/render/pickboundingvolumejob/tst_pickboundingvolumejob.cpp b/tests/auto/render/pickboundingvolumejob/tst_pickboundingvolumejob.cpp
index 3e752e6c3..5ebf10338 100644
--- a/tests/auto/render/pickboundingvolumejob/tst_pickboundingvolumejob.cpp
+++ b/tests/auto/render/pickboundingvolumejob/tst_pickboundingvolumejob.cpp
@@ -1058,6 +1058,100 @@ private Q_SLOTS:
 
         arbiter.events.clear();
     }
+
+    void checkPickerGrabbing_data()
+    {
+        generateAllPickingSettingsCombinations();
+    }
+
+    void checkPickerGrabbing()
+    {
+        // GIVEN
+        QmlSceneReader sceneReader(QUrl("qrc:/testscene_dragenabledoverlapping.qml"));
+        QScopedPointer<Qt3DCore::QNode> root(qobject_cast<Qt3DCore::QNode *>(sceneReader.root()));
+        QVERIFY(root);
+
+        QList<Qt3DRender::QRenderSettings *> renderSettings = root->findChildren<Qt3DRender::QRenderSettings *>();
+        QCOMPARE(renderSettings.size(), 1);
+        Qt3DRender::QPickingSettings *settings = renderSettings.first()->pickingSettings();
+
+        QFETCH(Qt3DRender::QPickingSettings::PickMethod, pickMethod);
+        QFETCH(Qt3DRender::QPickingSettings::PickResultMode, pickResultMode);
+        QFETCH(Qt3DRender::QPickingSettings::FaceOrientationPickingMode, faceOrientationPickingMode);
+        settings->setPickMethod(pickMethod);
+        settings->setPickResultMode(pickResultMode);
+        settings->setFaceOrientationPickingMode(faceOrientationPickingMode);
+
+        QScopedPointer<Qt3DRender::TestAspect> test(new Qt3DRender::TestAspect(root.data()));
+        TestArbiter arbiter1;
+        TestArbiter arbiter2;
+
+        // Runs Required jobs
+        runRequiredJobs(test.data());
+
+        // THEN
+        QList<Qt3DRender::QObjectPicker *> pickers = root->findChildren<Qt3DRender::QObjectPicker *>();
+        QCOMPARE(pickers.size(), 2);
+
+        Qt3DRender::QObjectPicker *picker1 = nullptr;
+        Qt3DRender::QObjectPicker *picker2 = nullptr;
+        if (pickers.first()->objectName() == QLatin1String("Picker1")) {
+            picker1 = pickers.first();
+            picker2 = pickers.last();
+        } else {
+            picker1 = pickers.last();
+            picker2 = pickers.first();
+        }
+
+        Qt3DRender::Render::ObjectPicker *backendPicker1 = test->nodeManagers()->objectPickerManager()->lookupResource(picker1->id());
+        QVERIFY(backendPicker1);
+        Qt3DCore::QBackendNodePrivate::get(backendPicker1)->setArbiter(&arbiter1);
+
+        Qt3DRender::Render::ObjectPicker *backendPicker2 = test->nodeManagers()->objectPickerManager()->lookupResource(picker2->id());
+        QVERIFY(backendPicker2);
+        Qt3DCore::QBackendNodePrivate::get(backendPicker2)->setArbiter(&arbiter2);
+
+        QCOMPARE(test->renderSettings()->pickMethod(), pickMethod);
+        QCOMPARE(test->renderSettings()->pickResultMode(), pickResultMode);
+        QCOMPARE(test->renderSettings()->faceOrientationPickingMode(), faceOrientationPickingMode);
+
+        // WHEN -> Pressed on object
+        Qt3DRender::Render::PickBoundingVolumeJob pickBVJob;
+        initializePickBoundingVolumeJob(&pickBVJob, test.data());
+
+        QList<QMouseEvent> events;
+        events.push_back(QMouseEvent(QMouseEvent::MouseButtonPress, QPointF(320.0f, 303.0f), Qt::LeftButton, Qt::LeftButton, Qt::NoModifier));
+        pickBVJob.setMouseEvents(events);
+        bool earlyReturn = !pickBVJob.runHelper();
+
+        // THEN -> Pressed
+        QVERIFY(!earlyReturn);
+        QVERIFY(backendPicker1->isPressed());
+        Qt3DCore::QPropertyUpdatedChangePtr change = arbiter1.events.first().staticCast<Qt3DCore::QPropertyUpdatedChange>();
+        QCOMPARE(change->propertyName(), "pressed");
+
+        arbiter1.events.clear();
+
+        // WHEN -> Move on next object, show stay on previous picker unless all picks are requested
+        events.clear();
+        events.push_back(QMouseEvent(QMouseEvent::MouseMove, QPointF(280.0f, 303.0f), Qt::LeftButton, Qt::LeftButton, Qt::NoModifier));
+        pickBVJob.setMouseEvents(events);
+        earlyReturn = !pickBVJob.runHelper();
+
+        // THEN -> Moved over the second picker, is the first one still pressed
+        QVERIFY(!earlyReturn);
+        if (pickResultMode != Qt3DRender::QPickingSettings::AllPicks) {
+            QVERIFY(backendPicker1->isPressed());
+            change = arbiter1.events.first().staticCast<Qt3DCore::QPropertyUpdatedChange>();
+            QCOMPARE(change->propertyName(), "moved");
+        } else {
+            change = arbiter2.events.first().staticCast<Qt3DCore::QPropertyUpdatedChange>();
+            QCOMPARE(change->propertyName(), "entered");
+        }
+
+        arbiter1.events.clear();
+        arbiter2.events.clear();
+    }
 };
 
 QTEST_MAIN(tst_PickBoundingVolumeJob)
diff --git a/tests/manual/dragging/dragging.pro b/tests/manual/dragging/dragging.pro
new file mode 100644
index 000000000..77541effb
--- /dev/null
+++ b/tests/manual/dragging/dragging.pro
@@ -0,0 +1,14 @@
+!include( ../manual.pri ) {
+    error( "Couldn't find the manual.pri file!" )
+}
+
+QT += 3dcore 3drender 3dinput 3dquick qml quick 3dquickextras
+
+SOURCES += \
+    main.cpp
+
+OTHER_FILES += \
+    main.qml
+
+RESOURCES += \
+    dragging.qrc
diff --git a/tests/manual/dragging/dragging.qrc b/tests/manual/dragging/dragging.qrc
new file mode 100644
index 000000000..5f6483ac3
--- /dev/null
+++ b/tests/manual/dragging/dragging.qrc
@@ -0,0 +1,5 @@
+<RCC>
+    <qresource prefix="/">
+        <file>main.qml</file>
+    </qresource>
+</RCC>
diff --git a/tests/manual/dragging/main.cpp b/tests/manual/dragging/main.cpp
new file mode 100644
index 000000000..dba6e0bff
--- /dev/null
+++ b/tests/manual/dragging/main.cpp
@@ -0,0 +1,63 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <Qt3DQuickExtras/qt3dquickwindow.h>
+#include <QGuiApplication>
+
+int main(int argc, char* argv[])
+{
+    QGuiApplication app(argc, argv);
+    Qt3DExtras::Quick::Qt3DQuickWindow view;
+
+    view.setSource(QUrl("qrc:/main.qml"));
+    view.show();
+
+    return app.exec();
+}
diff --git a/tests/manual/dragging/main.qml b/tests/manual/dragging/main.qml
new file mode 100644
index 000000000..844b5066d
--- /dev/null
+++ b/tests/manual/dragging/main.qml
@@ -0,0 +1,178 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt3D module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import Qt3D.Core 2.0
+import Qt3D.Render 2.0
+import Qt3D.Input 2.0
+import Qt3D.Extras 2.0
+
+Entity {
+    id: sceneRoot
+
+    Camera {
+        id: camera
+        projectionType: CameraLens.PerspectiveProjection
+        fieldOfView: 45
+        aspectRatio: 16/9
+        nearPlane : 0.1
+        farPlane : 1000.0
+        position: Qt.vector3d( 0.0, 0.0, 20.0 )
+        upVector: Qt.vector3d( 0.0, 1.0, 0.0 )
+        viewCenter: Qt.vector3d( 0.0, 0.0, 0.0 )
+    }
+
+    RenderSettings {
+        id : external_forward_renderer
+        activeFrameGraph : ForwardRenderer {
+            camera: camera
+            clearColor: "white"
+        }
+    }
+
+    // Event Source will be set by the Qt3DQuickWindow
+    InputSettings { id: inputSettings }
+
+    components: [external_forward_renderer, inputSettings]
+
+    Entity {
+        components: [
+            DirectionalLight {
+                worldDirection: Qt.vector3d(0., 0., -1.0).normalized();
+                color: "white"
+                intensity: 1.
+            }
+        ]
+    }
+
+
+    Entity {
+        id: mainEntity
+        objectName: "mainEntity"
+
+        ConeMesh {
+            id: coneMesh
+            length: 4
+        }
+
+        PhongMaterial {
+            id: coneMaterial
+            diffuse: "yellow"
+        }
+
+        Transform {
+            id: coneTransform
+            scale: 1.5
+            translation: Qt.vector3d(0, 2, 0)
+        }
+
+        components: [ coneMesh, coneMaterial, coneTransform ]
+    }
+
+
+
+    Entity {
+        id: draggerEntity
+        objectName: "draggerEntity"
+        property vector3d position: Qt.vector3d(0, 0, 0)
+
+        CylinderMesh {
+            id: mesh
+            radius: .5
+            length: 3
+            rings: 2
+            slices: 20
+        }
+
+        Transform {
+            id: transform
+            rotationZ: 90
+            translation: draggerEntity.position.plus(Qt.vector3d(0, -5, 0))
+        }
+
+        PhongMaterial {
+            id: material
+            diffuse: picker.pressed ? "lightgreen" : "green"
+        }
+
+        ObjectPicker {
+            id: picker
+            property double lastPos: 0
+            dragEnabled: true
+            onPressed: {
+                lastPos = pick.worldIntersection.x
+            }
+            onMoved: {
+                var x = draggerEntity.position.x + (pick.worldIntersection.x - lastPos)
+                if (x > 5) x = 5
+                if (x < -5) x = -5
+                draggerEntity.position.x = x
+                lastPos = pick.worldIntersection.x
+                coneMesh.bottomRadius = 1. + (x / 7.)
+            }
+        }
+
+        components: [ mesh, material, transform, picker ]
+    }
+
+
+    Entity {
+        id: obstructionEntity
+
+        components: [
+            CuboidMesh { },
+            PhongMaterial { diffuse: "blue" },
+            Transform {
+                scale: 2
+                translation: Qt.vector3d(4, -5, 0)
+            },
+            ObjectPicker { }
+        ]
+    }
+}
diff --git a/tests/manual/manual.pro b/tests/manual/manual.pro
index bfb95bfc2..fa1ddbcc7 100644
--- a/tests/manual/manual.pro
+++ b/tests/manual/manual.pro
@@ -15,6 +15,7 @@ SUBDIRS += \
     cylinder-qml \
     deferred-renderer-cpp \
     deferred-renderer-qml \
+    dragging \
     dynamicscene-cpp \
     enabled-qml \
     gltf \