Merge pull request #8398 from AnalyticalGraphicsInc/underEllipsoidCullingFix_Primitives

Make primitives/entities not cull when below ellipsoid but above terrain

Author: lilleyse

CHANGES.md

@@ -4,7 +4,8 @@ Change Log
 ### 1.65.0 - 2019-01-02
 
 ##### Fixes :wrench:
-* Fix Geocoder auto-complete suggestions when hosted inside Web Components. [#8425](https://github.com/AnalyticalGraphicsInc/cesium/pull/8425)
+* Fixed Geocoder auto-complete suggestions when hosted inside Web Components. [#8425](https://github.com/AnalyticalGraphicsInc/cesium/pull/8425)
+* Fixed primitive culling when below the ellipsoid but above terrain. [#8398](https://github.com/AnalyticalGraphicsInc/cesium/pull/8398)
 
 ### 1.64.0 - 2019-12-02
 

Source/Scene/FrameState.js

@@ -391,6 +391,14 @@ import SceneMode from './SceneMode.js';
          * @type {Cesium3DTilePassState}
          */
         this.tilesetPassState = undefined;
+
+        /**
+         * The minimum terrain height out of all rendered terrain tiles. Used to improve culling for objects underneath the ellipsoid but above terrain.
+         *
+         * @type {Number}
+         * @default 0.0
+         */
+        this.minimumTerrainHeight = 0.0;
     }
 
     /**

Source/Scene/GlobeSurfaceTileProvider.js

@@ -420,7 +420,10 @@ import TileSelectionResult from './TileSelectionResult.js';
             }
 
             for (var tileIndex = 0, tileLength = tilesToRender.length; tileIndex < tileLength; ++tileIndex) {
-                addDrawCommandsForTile(this, tilesToRender[tileIndex], frameState);
+                var tile = tilesToRender[tileIndex];
+                var tileBoundingRegion = tile.data.tileBoundingRegion;
+                addDrawCommandsForTile(this, tile, frameState);
+                frameState.minimumTerrainHeight = Math.min(frameState.minimumTerrainHeight, tileBoundingRegion.minimumHeight);
             }
         }
     };

Source/Scene/Scene.js

@@ -1711,7 +1711,8 @@ import View from './View.js';
         var globe = scene.globe;
         if (scene._mode === SceneMode.SCENE3D && defined(globe) && globe.show) {
             var ellipsoid = globe.ellipsoid;
-            scratchOccluderBoundingSphere.radius = ellipsoid.minimumRadius;
+            var minimumTerrainHeight = scene.frameState.minimumTerrainHeight;
+            scratchOccluderBoundingSphere.radius = ellipsoid.minimumRadius + minimumTerrainHeight;
             scratchOccluder = Occluder.fromBoundingSphere(scratchOccluderBoundingSphere, scene.camera.positionWC, scratchOccluder);
             return scratchOccluder;
         }
@@ -1754,6 +1755,7 @@ import View from './View.js';
         frameState.cullingVolume = camera.frustum.computeCullingVolume(camera.positionWC, camera.directionWC, camera.upWC);
         frameState.occluder = getOccluder(this);
         frameState.terrainExaggeration = this._terrainExaggeration;
+        frameState.minimumTerrainHeight = 0.0;
         frameState.minimumDisableDepthTestDistance = this._minimumDisableDepthTestDistance;
         frameState.invertClassification = this.invertClassification;
         frameState.useLogDepth = this._logDepthBuffer && !(this.camera.frustum instanceof OrthographicFrustum || this.camera.frustum instanceof OrthographicOffCenterFrustum);