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ArcGIS Runtime SDK for Qt

Feature layer rendering mode (scene)

Sample Viewer View Sample on GitHub

Render features in a scene statically or dynamically by setting the feature layer rendering mode.

Use case

In dynamic rendering mode, features and graphics are stored on the GPU. As a result, dynamic rendering mode is good for moving objects and for maintaining graphical fidelity during extent changes, since individual graphic changes can be efficiently applied directly to the GPU state. This gives the map or scene a seamless look and feel when interacting with it. The number of features and graphics has a direct impact on GPU resources, so large numbers of features or graphics can affect the responsiveness of maps or scenes to user interaction. Ultimately, the number and complexity of features and graphics that can be rendered in dynamic rendering mode is dependent on the power and memory of the device's GPU.

In static rendering mode, features and graphics are rendered only when needed (for example, after an extent change) and offloads a significant portion of the graphical processing onto the CPU. As a result, less work is required by the GPU to draw the graphics, and the GPU can spend its resources on keeping the UI interactive. Use this mode for stationary graphics, complex geometries, and very large numbers of features or graphics. The number of features and graphics has little impact on frame render time, meaning it scales well, and pushes a constant GPU payload. However, rendering updates is CPU and system memory intensive, which can have an impact on device battery life.

How to use the sample

Use the 'Animated Zoom' button to trigger the same zoom animation on both static and dynamicly rendered scenes.

How it works

Two Scenes are created, each containing several FeatureLayers. Prior to loading each Scene, several LoadSettings are set: preferredPointFeatureRenderingMode, preferredPolygonFeatureRenderingMode, and preferredPolylineFeatureRenderingMode. One Scene explicitly sets the rendering mode to be Static while the other sets the rendering mode to be Dynamic. The rendering mode can change the behavior and performance of the FeatureLayer depending on several factors with the underlying data. This sample animates the SceneView viewpoint between two Camera viewpoints, which helps display the differences between the two modes.

  1. Create a Scene and set several loadSettings: preferred[Point/Polyline/Polygon]FeatureRenderingMode(...).
  2. The rendering mode can be set to Enums.FeatureRenderingModeStatic, Enums.FeatureRenderingModeDynamic or Enums.FeatureRenderingModeAutomatic.
    • In Static rendering mode, the number of features and graphics has little impact on frame render time, meaning it scales well, however points don't stay screen-aligned and point/polyline/polygon objects are only redrawn once map view navigation is complete.
    • In Dynamic rendering mode, large numbers of features or graphics can affect the responsiveness of maps or scenes to user interaction, however points remain screen-aligned and point/polyline/polygon objects are continually redrawn while the map view is navigating.
  3. When left to automatic rendering, points are drawn dynamically and polylines and polygons statically.

Relevant API

  • Camera
  • FeatureLayer
  • FeatureLayer.renderingMode
  • LoadSettings
  • Scene
  • SceneView

Tags

3D, dynamic, feature layer, features, rendering, static

Sample Code

import QtQuick 2.6
import QtQuick.Controls 2.2
import Esri.ArcGISRuntime 100.9

Rectangle {
    id: rootRectangle
    clip: true
    width: 800
    height: 600

    property bool zoomedOut: true    

    SceneView {
        id: topSceneView
        anchors {
            left: parent.left
            right: parent.right
            top: parent.top
        }
        height: parent.height / 2

        Scene {
            // Set the preferred rendering mode to static
            LoadSettings {
                preferredPointFeatureRenderingMode: Enums.FeatureRenderingModeStatic
                preferredPolygonFeatureRenderingMode: Enums.FeatureRenderingModeStatic
                preferredPolylineFeatureRenderingMode: Enums.FeatureRenderingModeStatic
            }

            // Add the Feature Layers
            FeatureLayer {
                ServiceFeatureTable {
                    url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Energy/Geology/FeatureServer/0"
                }
            }

            FeatureLayer {
                ServiceFeatureTable {
                    url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Energy/Geology/FeatureServer/8"
                }
            }

            FeatureLayer {
                ServiceFeatureTable {
                    url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Energy/Geology/FeatureServer/9"
                }
            }

            onLoadStatusChanged: {
                if (loadStatus !== Enums.LoadStatusLoaded)
                    return;
                topSceneView.setViewpointCameraAndWait(zoomOutCamera);
            }
        }

        Rectangle {
            anchors {
                horizontalCenter: parent.horizontalCenter
                top: parent.top
                margins: 5
            }
            color: "white"
            radius: 5
            width: 200
            height: 30

            Text {
                anchors.centerIn: parent
                text: "Rendering Mode Static"
            }
        }
    }

    SceneView {
        id: bottomSceneView
        anchors {
            left: parent.left
            right: parent.right
            bottom: parent.bottom
        }
        height: parent.height / 2

        Scene {
            // Set the preferred rendering mode to dynamic
            LoadSettings {
                preferredPointFeatureRenderingMode: Enums.FeatureRenderingModeDynamic
                preferredPolygonFeatureRenderingMode: Enums.FeatureRenderingModeDynamic
                preferredPolylineFeatureRenderingMode: Enums.FeatureRenderingModeDynamic
            }

            // Add the Feature Layers
            FeatureLayer {
                ServiceFeatureTable {
                    url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Energy/Geology/FeatureServer/0"
                }
            }

            FeatureLayer {
                ServiceFeatureTable {
                    url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Energy/Geology/FeatureServer/8"
                }
            }

            FeatureLayer {
                ServiceFeatureTable {
                    url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Energy/Geology/FeatureServer/9"
                }
            }

            onLoadStatusChanged: {
                if (loadStatus !== Enums.LoadStatusLoaded)
                    return;
                bottomSceneView.setViewpointCameraAndWait(zoomOutCamera);
            }
        }

        Rectangle {
            anchors {
                horizontalCenter: parent.horizontalCenter
                top: parent.top
                margins: 5
            }
            color: "white"
            radius: 5
            width: 200
            height: 30

            Text {
                anchors.centerIn: parent
                text: "Rendering Mode Dynamic"
            }
        }
    }

    Camera {
        id: zoomOutCamera

        Point {
            x: -118.37
            y: 34.46
            spatialReference: SpatialReference { wkid: 4326 }
        }

        distance: 42000
        heading: 0
        pitch: 0
        roll: 0
    }

    Camera {
        id: zoomInCamera

        Point {
            x: -118.45
            y: 34.395
            spatialReference: SpatialReference { wkid: 4326 }
        }

        distance: 2500
        heading: 90
        pitch: 75
        roll: 0
    }

    Button {
        readonly property string stopText: "Stop Animation"
        readonly property string startText: "Start Animation"
        anchors {
            left: parent.left
            top: parent.top
            margins: 10
        }
        text: startText
        onClicked: {
            if (text === startText) {
                timer.start();
                text = stopText;
            } else {
                timer.stop();
                text = startText;
            }
        }
    }

    Timer {
        id: timer
        interval: 7000
        repeat: true
        triggeredOnStart: true
        onTriggered: {
            let camera;
            if (zoomedOut)
                camera = zoomInCamera;
            else
                camera = zoomOutCamera;
            topSceneView.setViewpointCameraAndSeconds(camera, 5);
            bottomSceneView.setViewpointCameraAndSeconds(camera, 5);
            zoomedOut = !zoomedOut;
        }
    }
}