Allow light position modification by user

Change-Id: I7efd56754bae16990fd11081493da0a37698f76b
Task-number: QTRD-1803
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

6 files changed, 88 insertions, 12 deletions

diff --git a/src/datavisualization/engine/abstract3dcontroller.cpp b/src/datavisualization/engine/abstract3dcontroller.cpp
index 08949c54..adfe461e 100644
--- a/src/datavisualization/engine/abstract3dcontroller.cpp
+++ b/src/datavisualization/engine/abstract3dcontroller.cpp
@@ -87,9 +87,7 @@ Abstract3DController::Abstract3DController(QRect initialViewport, Q3DScene *scen
     setActiveTheme(defaultTheme);
 
     m_scene->d_ptr->setViewport(initialViewport);
-
-    // Populate the scene
-    m_scene->activeLight()->setPosition(defaultLightPos);
+    m_scene->activeLight()->setAutoPosition(true);
 
     // Create initial default input handler
     QAbstract3DInputHandler *inputHandler;
diff --git a/src/datavisualization/engine/abstract3drenderer.cpp b/src/datavisualization/engine/abstract3drenderer.cpp
index 4a681554..dd3212ac 100644
--- a/src/datavisualization/engine/abstract3drenderer.cpp
+++ b/src/datavisualization/engine/abstract3drenderer.cpp
@@ -500,6 +500,11 @@ void Abstract3DRenderer::handleShadowQualityChange()
 {
     reInitShaders();
 
+    if (m_cachedScene->activeLight()->isAutoPosition()
+            || m_cachedShadowQuality > QAbstract3DGraph::ShadowQualityNone) {
+        m_cachedScene->d_ptr->setLightPositionRelativeToCamera(defaultLightPos);
+        emit needRender();
+    }
     if (m_isOpenGLES && m_cachedShadowQuality != QAbstract3DGraph::ShadowQualityNone) {
         emit requestShadowQuality(QAbstract3DGraph::ShadowQualityNone);
         qWarning("Shadows are not yet supported for OpenGL ES2");
@@ -1994,8 +1999,12 @@ void Abstract3DRenderer::updateCameraViewport()
         m_oldCameraTarget = adjustedTarget;
     }
     m_cachedScene->activeCamera()->d_ptr->updateViewMatrix(m_autoScaleAdjustment);
-    // Set light position (i.e rotate light with activeCamera, a bit above it)
-    m_cachedScene->d_ptr->setLightPositionRelativeToCamera(defaultLightPos);
+    // Set light position (i.e rotate light with activeCamera, a bit above it).
+    // Check if we want to use automatic light positioning even without shadows
+    if (m_cachedScene->activeLight()->isAutoPosition()
+            || m_cachedShadowQuality > QAbstract3DGraph::ShadowQualityNone) {
+        m_cachedScene->d_ptr->setLightPositionRelativeToCamera(defaultLightPos);
+    }
 }
 
 QT_END_NAMESPACE_DATAVISUALIZATION
diff --git a/src/datavisualization/engine/q3dlight.cpp b/src/datavisualization/engine/q3dlight.cpp
index bc337512..8c439023 100644
--- a/src/datavisualization/engine/q3dlight.cpp
+++ b/src/datavisualization/engine/q3dlight.cpp
@@ -37,7 +37,9 @@ QT_BEGIN_NAMESPACE_DATAVISUALIZATION
  * \brief Representation of a light source in 3D space.
  * \since QtDataVisualization 1.0
  *
- * Q3DLight represents a monochrome non variable light source in 3D space.
+ * Q3DLight represents a monochrome light source in 3D space.
+ *
+ * \note Default light has isAutoPosition() \c true.
  */
 
 /*!
@@ -48,7 +50,18 @@ QT_BEGIN_NAMESPACE_DATAVISUALIZATION
  * \instantiates Q3DLight
  * \brief Representation of a light source in 3D space.
  *
- * Light3D represents a monochrome non variable light source in 3D space.
+ * Light3D represents a monochrome light source in 3D space.
+ *
+ * \note Default light has autoPosition \c true.
+ */
+
+/*!
+ * \qmlproperty bool Light3D::autoPosition
+ * \since QtDataVisualization 1.3
+ * Holds a flag telling if the light position is automatic or not. If true, light position follows
+ * camera automatically.
+ * \note Has no effect if shadows are enabled. Remember to disable shadows before setting light's
+ * position, or it will be overwritten by automatic positioning, if autoPosition is false.
  */
 
 /*!
@@ -68,8 +81,31 @@ Q3DLight::~Q3DLight()
 {
 }
 
+/*!
+ * \property Q3DLight::autoPosition
+ * \since QtDataVisualization 5.9
+ * Holds a flag telling if the light position is automatic or not. If true, light position follows
+ * camera automatically.
+ * \note Has no effect if shadows are enabled. Remember to disable shadows before setting light's
+ * position, or it will be overwritten by automatic positioning, if isAutoPosition() is false.
+ */
+void Q3DLight::setAutoPosition(bool enabled)
+{
+    if (enabled != d_ptr->m_automaticLight) {
+        d_ptr->m_automaticLight = enabled;
+        setDirty(true);
+        emit autoPositionChanged(enabled);
+    }
+}
+
+bool Q3DLight::isAutoPosition()
+{
+    return d_ptr->m_automaticLight;
+}
+
 Q3DLightPrivate::Q3DLightPrivate(Q3DLight *q) :
-    q_ptr(q)
+    q_ptr(q),
+    m_automaticLight(false)
 {
 }
 
@@ -79,8 +115,11 @@ Q3DLightPrivate::~Q3DLightPrivate()
 
 void Q3DLightPrivate::sync(Q3DLight &other)
 {
-    Q_UNUSED(other);
-    // Do nothing. Only value light has to sync is the position, which we handle internally.
+    if (q_ptr->isDirty()) {
+        other.setPosition(q_ptr->position());
+        other.setAutoPosition(q_ptr->isAutoPosition());
+        q_ptr->setDirty(false);
+    }
 }
 
 QT_END_NAMESPACE_DATAVISUALIZATION
diff --git a/src/datavisualization/engine/q3dlight.h b/src/datavisualization/engine/q3dlight.h
index 8dc59d3a..582e600c 100644
--- a/src/datavisualization/engine/q3dlight.h
+++ b/src/datavisualization/engine/q3dlight.h
@@ -39,11 +39,18 @@ class Q3DLightPrivate;
 class QT_DATAVISUALIZATION_EXPORT Q3DLight : public Q3DObject
 {
     Q_OBJECT
+    Q_PROPERTY(bool autoPosition READ isAutoPosition WRITE setAutoPosition NOTIFY autoPositionChanged REVISION 1)
 
 public:
     explicit Q3DLight(QObject *parent = Q_NULLPTR);
     virtual ~Q3DLight();
 
+    void setAutoPosition(bool enabled);
+    bool isAutoPosition();
+
+Q_SIGNALS:
+    Q_REVISION(1) void autoPositionChanged(bool autoPosition);
+
 private:
     QScopedPointer<Q3DLightPrivate> d_ptr;
 
diff --git a/src/datavisualization/engine/q3dlight_p.h b/src/datavisualization/engine/q3dlight_p.h
index 2e22be47..afb3330b 100644
--- a/src/datavisualization/engine/q3dlight_p.h
+++ b/src/datavisualization/engine/q3dlight_p.h
@@ -57,6 +57,7 @@ public:
     void sync(Q3DLight &other);
 
 public:
+    bool m_automaticLight;
     Q3DLight *q_ptr;
 };
 
diff --git a/src/datavisualization/engine/q3dobject.cpp b/src/datavisualization/engine/q3dobject.cpp
index 42c9ccd9..f7757293 100644
--- a/src/datavisualization/engine/q3dobject.cpp
+++ b/src/datavisualization/engine/q3dobject.cpp
@@ -43,6 +43,28 @@ QT_BEGIN_NAMESPACE_DATAVISUALIZATION
 */
 
 /*!
+   \qmltype Object3D
+   \inqmlmodule QtDataVisualization
+   \since QtDataVisualization 1.0
+   \ingroup datavisualization_qml
+   \instantiates Q3DObject
+   \brief Simple baseclass for all the objects in the 3D scene.
+
+    Object3D is an uncreatable base type that contains only position information for an object in
+    3D scene. The object is considered to be a single point in the coordinate space without
+    dimensions.
+*/
+
+/*!
+ * \qmlproperty vector3d Object3D::position
+ *
+ * This property contains the 3D position of the object.
+ *
+ * \note Currently setting this property has no effect for Camera3D, as the position is handled
+ * internally.
+ */
+
+/*!
  * Constructs a new 3D object with position set to origin by default. An
  * optional \a parent parameter can be given and is then passed to QObject constructor.
  */
@@ -84,8 +106,8 @@ Q3DScene *Q3DObject::parentScene()
  *
  * This property contains the 3D position of the object.
  *
- * \note Currently setting this property has no effect, as the positions of Q3DObjects in the
- * scene are handled internally.
+ * \note Currently setting this property has no effect for Q3DCamera, as the position is handled
+ * internally.
  */
 QVector3D Q3DObject::position() const
 {