Added RTC_CENTER property support to b3dm

CHANGES.md

@@ -17,6 +17,7 @@ Change Log
   * The `PostProcessStageLibrary.createBlackAndWhiteStage` and `PostProcessStageLibrary.createSilhouetteStage` have per-feature support.
 * Added CZML support for `zIndex` for `corridor`, `ellipse`, `polygon`, `polyline` and `rectangle`. [#6708](https://github.com/AnalyticalGraphicsInc/cesium/pull/6708)
 * Added CZML `clampToGround` option for `polyline`. [#6706](https://github.com/AnalyticalGraphicsInc/cesium/pull/6706)
+* Added support for `RTC_CENTER` property in batched 3D model tilesets to conform to the updated [3D Tiles spec](https://github.com/AnalyticalGraphicsInc/3d-tiles/issues/263). [#6488](https://github.com/AnalyticalGraphicsInc/cesium/issues/6488)
 * Added `heightReference` and `extrudedHeightReference` properties to `CorridorGraphics`, `EllipseGraphics`, `PolygonGraphics` and `RectangleGraphics`. [#6717](https://github.com/AnalyticalGraphicsInc/cesium/pull/6717)
   * This can be used in conjunction with the `height` and/or `extrudedHeight` properties to clamp the geometry to terrain or set the height relative to terrain.
   * Note, this will not make the geometry conform to terrain.  Extruded geoemtry that is clamped to the ground will have a flat top will sinks into the terrain at the base.

Source/Scene/Batched3DModel3DTileContent.js

@@ -1,5 +1,7 @@
 define([
+        '../Core/Cartesian3',
         '../Core/Color',
+        '../Core/ComponentDatatype',
         '../Core/defaultValue',
         '../Core/defined',
         '../Core/defineProperties',
@@ -9,6 +11,7 @@ define([
         '../Core/FeatureDetection',
         '../Core/getBaseUri',
         '../Core/getStringFromTypedArray',
+        '../Core/Matrix4',
         '../Core/RequestType',
         '../Core/RuntimeError',
         '../Renderer/Pass',
@@ -20,7 +23,9 @@ define([
         './Model',
         './ModelUtility'
     ], function(
+        Cartesian3,
         Color,
+        ComponentDatatype,
         defaultValue,
         defined,
         defineProperties,
@@ -30,6 +35,7 @@ define([
         FeatureDetection,
         getBaseUri,
         getStringFromTypedArray,
+        Matrix4,
         RequestType,
         RuntimeError,
         Pass,
@@ -73,6 +79,9 @@ define([
         this._batchIdAttributeName = undefined;
         this._diffuseAttributeOrUniformName = {};
 
+        this._rtcCenterTransform = undefined;
+        this._contentModelMatrix = undefined;
+
         this.featurePropertiesDirty = false;
 
         initialize(this, arrayBuffer, byteOffset);
@@ -346,6 +355,14 @@ define([
             primitive : tileset
         };
 
+        content._rtcCenterTransform = Matrix4.clone(Matrix4.IDENTITY);
+        var rtcCenter = featureTable.getGlobalProperty('RTC_CENTER', ComponentDatatype.FLOAT, 3);
+        if (defined(rtcCenter)) {
+            content._rtcCenterTransform = Matrix4.fromTranslation(Cartesian3.fromArray(rtcCenter), content._rtcCenterTransform);
+        }
+
+        content._contentModelMatrix = Matrix4.multiply(tile.computedTransform, content._rtcCenterTransform, new Matrix4());
+
         if (!defined(tileset.classificationType)) {
             // PERFORMANCE_IDEA: patch the shader on demand, e.g., the first time show/color changes.
             // The pick shader still needs to be patched.
@@ -356,7 +373,7 @@ define([
                 opaquePass : Pass.CESIUM_3D_TILE, // Draw opaque portions of the model during the 3D Tiles pass
                 basePath : resource,
                 requestType : RequestType.TILES3D,
-                modelMatrix : tile.computedTransform,
+                modelMatrix: content._contentModelMatrix,
                 upAxis : tileset._gltfUpAxis,
                 forwardAxis : Axis.X,
                 shadows: tileset.shadows,
@@ -377,7 +394,7 @@ define([
                 cull : false,           // The model is already culled by 3D Tiles
                 basePath : resource,
                 requestType : RequestType.TILES3D,
-                modelMatrix : tile.computedTransform,
+                modelMatrix: content._contentModelMatrix,
                 upAxis : tileset._gltfUpAxis,
                 forwardAxis : Axis.X,
                 debugWireframe : tileset.debugWireframe,
@@ -438,7 +455,10 @@ define([
         // the content's resource loading.  In the READY state, it will
         // actually generate commands.
         this._batchTable.update(tileset, frameState);
-        this._model.modelMatrix = this._tile.computedTransform;
+
+        this._contentModelMatrix = Matrix4.multiply(this._tile.computedTransform, this._rtcCenterTransform, this._contentModelMatrix);
+        this._model.modelMatrix = this._contentModelMatrix;
+
         this._model.shadows = this._tileset.shadows;
         this._model.debugWireframe = this._tileset.debugWireframe;
 

Specs/Data/Cesium3DTiles/Batched/BatchedWithRtcCenter/tileset.json

@@ -0,0 +1,59 @@
+{
+  "asset": {
+    "version": "1.0"
+  },
+  "properties": {
+    "id": {
+      "minimum": 0,
+      "maximum": 9
+    },
+    "Longitude": {
+      "minimum": -1.3196972173766555,
+      "maximum": -1.3196718547473905
+    },
+    "Latitude": {
+      "minimum": 0.6988624606923348,
+      "maximum": 0.6988888301460953
+    },
+    "Height": {
+      "minimum": 6.2074098233133554,
+      "maximum": 12.83180232718587
+    }
+  },
+  "geometricError": 70,
+  "root": {
+    "transform": [
+      0.9686356343768792,
+      0.24848542777253735,
+      0,
+      0,
+      -0.15986460744966327,
+      0.623177611820219,
+      0.765567091384559,
+      0,
+      0.19023226619126932,
+      -0.7415555652213445,
+      0.6433560667227647,
+      0,
+      1215011.9317263428,
+      -4736309.3434217675,
+      4081602.0044800863,
+      1
+    ],
+    "refine": "ADD",
+    "boundingVolume": {
+      "region": [
+        -1.3197004795898053,
+        0.6988582109,
+        -1.3196595204101946,
+        0.6988897891,
+        0,
+        20
+      ]
+    },
+    "geometricError": 0,
+    "content": {
+      "url": "batchedWithRtcCenter.b3dm"
+    }
+  }
+}

Specs/Scene/Batched3DModel3DTileContentSpec.js

@@ -4,6 +4,7 @@ defineSuite([
         'Core/Color',
         'Core/HeadingPitchRange',
         'Core/HeadingPitchRoll',
+        'Core/Matrix4',
         'Core/Transforms',
         'Scene/ClippingPlane',
         'Scene/ClippingPlaneCollection',
@@ -16,6 +17,7 @@ defineSuite([
         Color,
         HeadingPitchRange,
         HeadingPitchRoll,
+        Matrix4,
         Transforms,
         ClippingPlane,
         ClippingPlaneCollection,
@@ -42,6 +44,7 @@ defineSuite([
     var deprecated1Url = './Data/Cesium3DTiles/Batched/BatchedDeprecated1/tileset.json';
     var deprecated2Url = './Data/Cesium3DTiles/Batched/BatchedDeprecated2/tileset.json';
     var gltfZUpUrl = './Data/Cesium3DTiles/Batched/BatchedGltfZUp/tileset.json';
+    var withRtcCenterUrl = './Data/Cesium3DTiles/Batched/BatchedWithRtcCenter/tileset.json';
 
     function setCamera(longitude, latitude) {
         // One feature is located at the center, point the camera there
@@ -371,6 +374,31 @@ defineSuite([
         });
     });
 
+    it('transforms model positions by RTC_CENTER property in the features table', function() {
+        return Cesium3DTilesTester.loadTileset(scene, withRtcCenterUrl).then(function(tileset) {
+            Cesium3DTilesTester.expectRenderTileset(scene, tileset);
+
+            var rtcTransform = tileset._root._content._rtcCenterTransform;
+            expect(rtcTransform).toEqual(Matrix4.fromTranslation(new Cartesian3(0.1, 0.2, 0.3)));
+
+            var expectedModelTransform = Matrix4.multiply(tileset._root.transform, rtcTransform, new Matrix4());
+            expect(tileset._root._content._contentModelMatrix).toEqual(expectedModelTransform);
+            expect(tileset._root._content._model._modelMatrix).toEqual(expectedModelTransform);
+
+             // Update tile transform
+            var newLongitude = -1.31962;
+            var newLatitude = 0.698874;
+            var newCenter = Cartesian3.fromRadians(newLongitude, newLatitude, 0.0);
+            var newHPR = new HeadingPitchRoll();
+            var newTransform = Transforms.headingPitchRollToFixedFrame(newCenter, newHPR);
+            tileset._root.transform = newTransform;
+            scene.renderForSpecs();
+
+            expectedModelTransform = Matrix4.multiply(tileset._root.computedTransform, rtcTransform, expectedModelTransform);
+            expect(tileset._root._content._model._modelMatrix).toEqual(expectedModelTransform);
+        });
+    });
+
     it('destroys', function() {
         return Cesium3DTilesTester.tileDestroys(scene, withoutBatchTableUrl);
     });