Show viewshed from geoelement in scene

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 // Copyright 2025 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 // // https://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. //  import 'dart:async'; import 'dart:io';  import 'package:arcgis_maps/arcgis_maps.dart'; import 'package:arcgis_maps_sdk_flutter_samples/common/common.dart'; import 'package:flutter/material.dart'; import 'package:path_provider/path_provider.dart';  class ShowViewshedFromGeoelementInScene extends StatefulWidget {  const ShowViewshedFromGeoelementInScene({super.key});   @override  State<ShowViewshedFromGeoelementInScene> createState() =>  _ShowViewshedFromGeoelementInSceneState(); }  class _ShowViewshedFromGeoelementInSceneState  extends State<ShowViewshedFromGeoelementInScene>  with SampleStateSupport {  // Create a controller for the scene view.  final _sceneViewController = ArcGISSceneView.createController();   // The graphic for the tank.  Graphic? _tankGraphic;   // Timer for animation.  Timer? _animationTimer;   // Waypoint for tank graphic.  ArcGISPoint? _waypoint;   // A flag for when the map view is ready and controls can be used.  var _ready = false;   @override  Widget build(BuildContext context) {  return Scaffold(  body: SafeArea(  top: false,  left: false,  right: false,  child: Stack(  children: [  // Add a scene view to the widget tree and set a controller.  ArcGISSceneView(  controllerProvider: () => _sceneViewController,  onSceneViewReady: onSceneViewReady,  onTap: onTap,  ),  // Display a progress indicator and prevent interaction until state is ready.  LoadingIndicator(visible: !_ready),  // Banner at the top.  SafeArea(  child: IgnorePointer(  child: Container(  width: double.infinity,  padding: const EdgeInsets.all(10),  color: Colors.black.withValues(alpha: 0.5),  child: const Text(  'Tap on the map to move the tank and update the viewshed.',  textAlign: TextAlign.center,  style: TextStyle(color: Colors.white, fontSize: 16),  ),  ),  ),  ),  ],  ),  ),  );  }   // Called when the scene view is ready.  Future<void> onSceneViewReady() async {  // Create and configure the scene with elevation.  final scene = _createScene();  // Assign the scene to the scene view controller.  _sceneViewController.arcGISScene = scene;   // Load the tank graphic from the local data.  _tankGraphic = await _loadTankGraphic();   // Add the tank graphic to the scene.  _addTankToScene(_tankGraphic!);   // Set up the orbit camera controller to follow the tank.  _setupCameraController(_tankGraphic!);   // Add the viewshed to the scene.  _addViewshedToScene(_tankGraphic!);   setState(() => _ready = true);  }   // Creates a scene with an imagery basemap and adds elevation data.  ArcGISScene _createScene() {  final scene = ArcGISScene.withBasemapStyle(BasemapStyle.arcGISImagery);   // Add world elevation source to the scene's surface.  final elevationSource = ArcGISTiledElevationSource.withUri(  Uri.parse(  'https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer',  ),  );  scene.baseSurface.elevationSources.add(elevationSource);   // Create the building layer and add it to the scene.  final buildingsLayer = ArcGISSceneLayer.withUri(  Uri.parse(  'https://tiles.arcgis.com/tiles/P3ePLMYs2RVChkJx/arcgis/rest/services/Buildings_Brest/SceneServer/layers/0',  ),  );  scene.operationalLayers.add(buildingsLayer);   return scene;  }   // Convert the tapped location into a waypoint within the scene and initiate the tank's animation towards the waypoint.  Future<void> onTap(Offset localPosition) async {  // Convert localPosition to scenePoint.  final scenePoint = await _sceneViewController.screenToLocation(  screen: localPosition,  );   setState(() => _waypoint = scenePoint);   _startTankAnimation();  }   // Animate the tank toward the waypoint.  void _startTankAnimation() {  // Cancel any existing timer.  _animationTimer?.cancel();  _animationTimer = Timer.periodic(const Duration(milliseconds: 100), (  timer,  ) async {  if (_tankGraphic == null || _waypoint == null) return;   final tempPos = _tankGraphic!.geometry! as ArcGISPoint;   final currentPos = ArcGISPoint(  x: tempPos.x,  y: tempPos.y,  spatialReference: SpatialReference.wgs84,  );  final target = ArcGISPoint(  x: _waypoint!.x,  y: _waypoint!.y,  spatialReference: SpatialReference.wgs84,  );   // Use geodetic distance to get distance and azimuth.  final result = GeometryEngine.distanceGeodetic(  point1: currentPos,  point2: target,  distanceUnit: LinearUnit(unitId: LinearUnitId.meters),  azimuthUnit: AngularUnit(unitId: AngularUnitId.degrees),  curveType: GeodeticCurveType.geodesic,  );   final distance = result.distance;  final azimuth = result.azimuth1;   // Stop if close enough.  if (distance <= 5) {  _waypoint = null;  timer.cancel();  return;  }   // Move a small step toward the waypoint.  const step = 1.0; // meters  final movedPoints = GeometryEngine.moveGeodetic(  pointCollection: [currentPos],  distance: step,  azimuth: azimuth,  distanceUnit: LinearUnit(unitId: LinearUnitId.meters),  azimuthUnit: AngularUnit(unitId: AngularUnitId.degrees),  curveType: GeodeticCurveType.geodesic,  );   if (movedPoints.isEmpty) return;   final newPoint = movedPoints.first;  _tankGraphic!.geometry = newPoint;   // Update heading.  final currentHeading =  (_tankGraphic!.attributes['HEADING'] as num?)?.toDouble() ?? 0.0;   final headingDiff = shortestAngle(currentHeading, azimuth);  final newHeading = currentHeading + headingDiff / 10;   _tankGraphic!.attributes['HEADING'] = newHeading;  });  }   // Calculate shortest angle to rotate.  double shortestAngle(double from, double to) {  final difference = (to - from + 540) % 360 - 180;  return difference;  }   // Loads the 3D tank model from local sample data and returns it as a Graphic.  Future<Graphic> _loadTankGraphic() async {  const downloadFileName = 'bradley_low_3ds';   final appDir = await getApplicationDocumentsDirectory();  final zipFile = File('${appDir.absolute.path}/$downloadFileName.zip');  if (!zipFile.existsSync()) {  await downloadSampleDataWithProgress(  itemIds: ['07d62a792ab6496d9b772a24efea45d0'],  destinationFiles: [zipFile],  );  }   final tankModelPath =  '${appDir.absolute.path}/$downloadFileName/bradle.3ds';   // Define the tank symbol.  final tankSymbol =  ModelSceneSymbol.withUri(uri: Uri.parse(tankModelPath), scale: 10)  ..heading = 90  ..anchorPosition = SceneSymbolAnchorPosition.bottom;   // Return the graphic that combines geometry and symbol.  return Graphic(  geometry: ArcGISPoint(x: -4.506390, y: 48.385624),  attributes: {'HEADING': 0.0},  symbol: tankSymbol,  );  }   // Adds the tank graphic to a graphics overlay and sets the initial viewpoint.  void _addTankToScene(Graphic tankGraphic) {  final graphicsOverlay = GraphicsOverlay()  ..graphics.add(tankGraphic)  ..sceneProperties = LayerSceneProperties(  surfacePlacement: SurfacePlacement.relative,  );   // Configure the heading expression for the tank; this will allow the  // viewshed to update automatically based on the tank's position.  final renderer = SimpleRenderer()  ..sceneProperties.headingExpression = '[HEADING]'  ..sceneProperties.pitchExpression = '[PITCH]'  ..sceneProperties.rollExpression = '[ROLL]';  graphicsOverlay.renderer = renderer;   _sceneViewController.graphicsOverlays.add(graphicsOverlay);  }   // Add viewshed to the scene.  void _addViewshedToScene(Graphic tankGraphic) {  // Create a GeoElementViewshed attached to the scene.  final geoElementViewshed =  GeoElementViewshed(  geoElement: tankGraphic,  horizontalAngle: 90,  verticalAngle: 40,  headingOffset: 0,  pitchOffset: 0,  minDistance: 0.1,  maxDistance: 250,  )  // Offset the observer location to the front of the tank.  ..offsetZ = 0.5  ..offsetY = 4;   // Create an Analysis Overlay and add the viewshed to it.  final analysisOverlay = AnalysisOverlay()..analyses.add(geoElementViewshed);   // Add the analysis overlay to the scene view.  _sceneViewController.analysisOverlays.add(analysisOverlay);  }   // Configures the orbit camera controller for the tank graphic.  void _setupCameraController(Graphic tankGraphic) {  final cameraController = OrbitGeoElementCameraController(  targetGeoElement: tankGraphic,  distance: 200,  );  _sceneViewController.cameraController = cameraController;  } }