Update the orientation of a graphic using expressions based on its attributes.
      
   
    
Use case
Instead of reading the attribute and changing the rotation on the symbol for a single graphic (a manual CPU operation), you can bind the rotation to an expression that applies to the whole overlay (an automatic GPU operation). This usually results in a noticeable performance boost (smooth rotations).
How to use the sample
Adjust the heading and pitch sliders to rotate the cone.
How it works
- Create a new graphics overlay.
- Create a simple renderer and set its scene properties.
- Set the heading expression to [HEADING].
- Apply the renderer to the graphics overlay.
- Create a graphic and add it to the overlay.
- To update the graphic's rotation, update the HEADINGorPITCHproperty in the graphic's attributes.
Relevant API
- Graphic::attributes
- GraphicsOverlay
- SceneProperties
- SceneProperties::headingExpression
- SceneProperties::pitchExpression
- SimpleRenderer
- SimpleRenderer::sceneProperties
Tags
3D, expression, graphics, heading, pitch, rotation, scene, symbology
Sample Code
// [WriteFile Name=ScenePropertiesExpressions, Category=Scenes]
// [Legal]
// Copyright 2019 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// [Legal]
#ifdef PCH_BUILD
#include "pch.hpp"
#endif // PCH_BUILD
// sample headers
#include "ScenePropertiesExpressions.h"
// ArcGIS Maps SDK headers
#include "ArcGISTiledElevationSource.h"
#include "AttributeListModel.h"
#include "Basemap.h"
#include "Camera.h"
#include "ElevationSourceListModel.h"
#include "Graphic.h"
#include "GraphicListModel.h"
#include "GraphicsOverlay.h"
#include "GraphicsOverlayListModel.h"
#include "LayerSceneProperties.h"
#include "MapTypes.h"
#include "Point.h"
#include "RendererSceneProperties.h"
#include "Scene.h"
#include "SceneQuickView.h"
#include "SceneViewTypes.h"
#include "SimpleMarkerSceneSymbol.h"
#include "SimpleRenderer.h"
#include "SpatialReference.h"
#include "Surface.h"
#include "SymbolTypes.h"
using namespace Esri::ArcGISRuntime;
namespace
{
  const QString HEADING("HEADING");
  const QString PITCH("PITCH");
}
ScenePropertiesExpressions::ScenePropertiesExpressions(QObject* parent /* = nullptr */):
  QObject(parent),
  m_scene(new Scene(BasemapStyle::ArcGISImageryStandard, this))
{
  // create a new elevation source from Terrain3D REST service
  ArcGISTiledElevationSource* elevationSource = new ArcGISTiledElevationSource(
        QUrl("https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer"), this);
  // add the elevation source to the scene to display elevation
  m_scene->baseSurface()->elevationSources()->append(elevationSource);
  m_graphicsOverlay = new GraphicsOverlay(this);
  m_graphicsOverlay->setSceneProperties(LayerSceneProperties(SurfacePlacement::Relative));
  // Create a SimpleRenderer and set expressions on its scene properties.
  // Then, set the renderer to the graphics overlay with GraphicsOverlay.setRenderer(renderer).
  SimpleRenderer* renderer3D = new SimpleRenderer(this);
  RendererSceneProperties renderProperties = renderer3D->sceneProperties();
  renderProperties.setHeadingExpression(QString("[%1]").arg(HEADING));
  renderProperties.setPitchExpression(QString("[%1]").arg(PITCH));
  renderer3D->setSceneProperties(renderProperties);
  m_graphicsOverlay->setRenderer(renderer3D);
}
ScenePropertiesExpressions::~ScenePropertiesExpressions() = default;
void ScenePropertiesExpressions::init()
{
  // Register classes for QML
  qmlRegisterType<SceneQuickView>("Esri.Samples", 1, 0, "SceneView");
  qmlRegisterType<ScenePropertiesExpressions>("Esri.Samples", 1, 0, "ScenePropertiesExpressionsSample");
}
SceneQuickView* ScenePropertiesExpressions::sceneView() const
{
  return m_sceneView;
}
// Set the view (created in QML)
void ScenePropertiesExpressions::setSceneView(SceneQuickView* sceneView)
{
  if (!sceneView || sceneView == m_sceneView)
  {
    return;
  }
  m_sceneView = sceneView;
  m_sceneView->setArcGISScene(m_scene);
  // create a camera
  const double latitude = 32.09;
  const double longitude = -118.71;
  const double altitude = 100000.0;
  const double heading = 0.0;
  const double pitch = 45.0;
  const double roll = 0.0;
  const int coneDimension = 10000;
  Camera camera(latitude - 1.0, // place the camera arbitrarily south of the cone
                longitude,
                altitude * 2, // place the camera arbitrarily higher than the cone
                heading,
                pitch,
                roll);
  // set the viewpoint
  m_sceneView->setViewpointCameraAndWait(camera);
  // add the graphics overlay to the scene view
  m_sceneView->graphicsOverlays()->append(m_graphicsOverlay);
  // create a scene symbol based on the current type
  SimpleMarkerSceneSymbol* smss = new SimpleMarkerSceneSymbol(SimpleMarkerSceneSymbolStyle::Cone, QColor("red"), 200, 200, 200, SceneSymbolAnchorPosition::Center, this);
  smss->setWidth(coneDimension);
  smss->setDepth(coneDimension);
  smss->setHeight(coneDimension * 2);
  // create a graphic using the symbol above and a point location
  m_graphic = new Graphic(Point(longitude, latitude, altitude, m_sceneView->spatialReference()), smss, this);
  m_graphic->attributes()->insertAttribute(HEADING, 0);
  m_graphic->attributes()->insertAttribute(PITCH, 0);
  // add the graphic to the graphics overlay
  m_graphicsOverlay->graphics()->append(m_graphic);
  emit sceneViewChanged();
}
void ScenePropertiesExpressions::setPitch(double pitchInDegrees)
{
  m_graphic->attributes()->replaceAttribute(PITCH, pitchInDegrees);
  emit pitchChanged();
}
double ScenePropertiesExpressions::pitch() const
{
  return m_graphic->attributes()->attributeValue(PITCH).toDouble();
}
void ScenePropertiesExpressions::setHeading(double headingInDegrees)
{
  m_graphic->attributes()->replaceAttribute(HEADING, headingInDegrees);
  emit headingChanged();
}
double ScenePropertiesExpressions::heading() const
{
  return m_graphic->attributes()->attributeValue(HEADING).toDouble();
}