Do not continuously update camera

Only call updateCamera if camera properties have changed.

Pick-to: 6.9
Task-number: QTBUG-136174
Change-Id: I94f6c80e4c9e9e36a6399058bdd74866d2c0b202
Reviewed-by: Sakaria Pouke <sakaria.pouke@qt.io>
Reviewed-by: Kwanghyo Park <kwanghyo.park@qt.io>
(cherry picked from commit 7deeaa5196)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/graphs3d/qml/qquickgraphsitem.cpp

@@ -2685,7 +2685,10 @@ void QQuickGraphsItem::synchData()
         m_changeTracker.axisZTitleOffsetChanged = false;
     }
 
-    updateCamera();
+    if (m_changeTracker.cameraChanged) {
+        updateCamera();
+        m_changeTracker.cameraChanged = false;
+    }
 
     QVector3D forward = camera()->forward();
     auto targetRotation = cameraTarget()->eulerRotation();
@@ -6279,6 +6282,7 @@ void QQuickGraphsItem::setCameraPreset(QtGraphs3D::CameraPreset preset)
         connect(this, &QQuickGraphsItem::cameraYRotationChanged, m_scene, &Q3DScene::needRender);
         connect(this, &QQuickGraphsItem::cameraZoomLevelChanged, m_scene, &Q3DScene::needRender);
     }
+    m_changeTracker.cameraChanged = true;
 }
 
 void QQuickGraphsItem::setCameraXRotation(float rotation)
@@ -6290,6 +6294,7 @@ void QQuickGraphsItem::setCameraXRotation(float rotation)
     if (rotation != m_xRotation) {
         m_xRotation = rotation;
         qCDebug(lcEvents3D, "%s x rotation: %.1f ", qUtf8Printable(QLatin1String(__FUNCTION__)), rotation);
+        m_changeTracker.cameraChanged = true;
         emit cameraXRotationChanged(m_xRotation);
     }
 }
@@ -6303,6 +6308,7 @@ void QQuickGraphsItem::setCameraYRotation(float rotation)
     if (rotation != m_yRotation) {
         m_yRotation = rotation;
         qCDebug(lcEvents3D, "%s y rotation: %.1f ", qUtf8Printable(QLatin1String(__FUNCTION__)), rotation);
+        m_changeTracker.cameraChanged = true;
         emit cameraYRotationChanged(m_yRotation);
     }
 }
@@ -6441,6 +6447,7 @@ void QQuickGraphsItem::setCameraZoomLevel(float level)
 
     m_zoomLevel = level;
     qCDebug(lcEvents3D, "%s zoom level: %.1f", qUtf8Printable(QLatin1String(__FUNCTION__)), level);
+    m_changeTracker.cameraChanged = true;
     emit cameraZoomLevelChanged(level);
 }
 
@@ -6489,6 +6496,7 @@ void QQuickGraphsItem::setCameraTargetPosition(QVector3D target)
     m_requestedTarget.setX(std::clamp(target.x(), -1.0f, 1.0f));
     m_requestedTarget.setY(std::clamp(target.y(), -1.0f, 1.0f));
     m_requestedTarget.setZ(std::clamp(target.z(), -1.0f, 1.0f));
+    m_changeTracker.cameraChanged = true;
     emit cameraTargetPositionChanged(target);
 }
 
@@ -7082,6 +7090,7 @@ void QQuickGraphsItem::setUpCamera()
         setCamera(m_oCamera);
     else
         setCamera(m_pCamera);
+    m_changeTracker.cameraChanged = true;
 }
 
 void QQuickGraphsItem::setUpLight()

src/graphs3d/qml/qquickgraphsitem_p.h

@@ -101,6 +101,7 @@ struct Abstract3DChangeBitField
     bool labelMarginChanged : 1;
     bool radialLabelOffsetChanged : 1;
     bool marginChanged : 1;
+    bool cameraChanged : 1;
 
     Abstract3DChangeBitField()
         : themeChanged(true)
@@ -156,6 +157,7 @@ struct Abstract3DChangeBitField
         , labelMarginChanged(true)
         , radialLabelOffsetChanged(true)
         , marginChanged(true)
+        , cameraChanged(true)
     {}
 };