Revert 10444 + 10446 (#10462) (#10464)

ansis · karimnaaji · web-flow · commit ab81e8d1553a · 2021-03-12T12:18:51.000-08:00
* Revert "Terrain: Don't load unnecessary tiles (#10444)" This reverts commit b00f90b. * Revert "Unit test for zoom 22 at Mile High City (#10446)" This reverts commit 1bacb2b. Co-authored-by: Karim Naaji <karim.naaji@gmail.com>
diff --git a/src/geo/transform.js b/src/geo/transform.js
@@ -541,13 +541,13 @@ class Transform {
             roundZoom?: boolean,
             reparseOverscaled?: boolean,
             renderWorldCopies?: boolean,
-            isTerrainDEM?: boolean
+            useElevationData?: boolean
         }
     ): Array<OverscaledTileID> {
         let z = this.coveringZoomLevel(options);
         const actualZ = z;
 
-        const useElevationData = this.elevation && !options.isTerrainDEM;
+        const useElevationData = !!options.useElevationData;
 
         if (options.minzoom !== undefined && z < options.minzoom) return [];
         if (options.maxzoom !== undefined && z > options.maxzoom) z = options.maxzoom;
@@ -569,14 +569,10 @@ class Transform {
         // No change of LOD behavior for pitch lower than 60 and when there is no top padding: return only tile ids from the requested zoom level
         const minZoom = this.pitch <= 60.0 && this._edgeInsets.top <= this._edgeInsets.bottom && !this._elevation ? z : 0;
 
-        // When calculating DEM tile cover, create deep AABB for nodes, to ensure they intersect frustum.  For other sources,
-        // use 2D tile cover: tile assumes center elevation until corresponding DEM cover is loaded to tell if additional
-        // tiles need to be loaded.
-        const maxRange = options.isTerrainDEM && this._elevation ? this._elevation.exaggeration() * 10000 : this._centerAltitude;
-        const minRange = options.isTerrainDEM && this._elevation ? -maxRange : this._centerAltitude;
+        const maxRange = this.elevation ? this.elevation.exaggeration() * 10000 : 0;
         const newRootTile = (wrap: number): any => {
             const max = maxRange;
-            const min = minRange;
+            const min = -maxRange;
             return {
                 // With elevation, this._elevation provides z coordinate values. For 2D:
                 // All tiles are on zero elevation plane => z difference is zero
@@ -698,7 +694,10 @@ class Transform {
 
                 const aabb = it.aabb.quadrant(i);
                 let tileID = null;
-                if (useElevationData) {
+                if (useElevationData && it.zoom > maxZoom - 6) {
+                    // Using elevation data for tiles helps clipping out tiles that are not visible and
+                    // precise distance calculation. it.zoom > maxZoom - 6 is an optimization as those before get subdivided
+                    // or they are so far at horizon that it doesn't matter.
                     tileID = new OverscaledTileID(it.zoom + 1 === maxZoom ? overscaledZ : it.zoom + 1, it.wrap, it.zoom + 1, childX, childY);
                     getAABBFromElevation(aabb, tileID);
                 }
diff --git a/src/source/source_cache.js b/src/source/source_cache.js
@@ -494,7 +494,7 @@ class SourceCache extends Evented {
                 maxzoom: this._source.maxzoom,
                 roundZoom: this._source.roundZoom && !updateForTerrain,
                 reparseOverscaled: this._source.reparseOverscaled,
-                isTerrainDEM: this.usedForTerrain
+                useElevationData: !!this.transform.elevation && !this.usedForTerrain
             });
 
             if (this._source.hasTile) {
diff --git a/src/terrain/terrain.js b/src/terrain/terrain.js
@@ -104,7 +104,8 @@ class ProxySourceCache extends SourceCache {
             minzoom: this._source.minzoom,
             maxzoom: this._source.maxzoom,
             roundZoom: this._source.roundZoom,
-            reparseOverscaled: this._source.reparseOverscaled
+            reparseOverscaled: this._source.reparseOverscaled,
+            useElevationData: true
         });
 
         const incoming: {[string]: string} = idealTileIDs.reduce((acc, tileID) => {
diff --git a/test/integration/render-tests/real-world/sanfrancisco-terrain-draped-movelayer/expected.png b/test/integration/render-tests/real-world/sanfrancisco-terrain-draped-movelayer/expected.png
diff --git a/test/integration/render-tests/real-world/sanfrancisco-terrain-draped-movelayer/style.json b/test/integration/render-tests/real-world/sanfrancisco-terrain-draped-movelayer/style.json
@@ -6,8 +6,8 @@
       "height": 512,
       "operations": [
         ["setStyle", "local://styles/sanfrancisco.json"],
-        ["setZoom", 15.0 ],
-        ["setCenter", [-122.45362, 37.77049] ],
+        ["setZoom", 15.1 ],
+        ["setCenter", [-122.448635, 37.7669995] ],
         ["wait"],
         ["addSource", "rgbterrain", {
           "type": "raster-dem",
@@ -19,8 +19,12 @@
         }],
         ["setTerrain", {"source": "rgbterrain"}],
         ["wait"],
+        ["setZoom", 15.2],
         ["moveLayer", "road_major", "road_minor"],
         ["moveLayer", "contour-line", "building"],
+        ["wait"],
+        ["setZoom", 15],
+        ["wait"],
         ["wait"]
       ]
     }
diff --git a/test/integration/render-tests/real-world/sanfrancisco-terrain-draped/expected.png b/test/integration/render-tests/real-world/sanfrancisco-terrain-draped/expected.png
diff --git a/test/integration/render-tests/real-world/sanfrancisco-terrain-draped/style.json b/test/integration/render-tests/real-world/sanfrancisco-terrain-draped/style.json
@@ -6,8 +6,8 @@
       "height": 512,
       "operations": [
         ["setStyle", "local://styles/sanfrancisco.json"],
-        ["setZoom", 15.0 ],
-        ["setCenter", [-122.45362, 37.77049] ],
+        ["setZoom", 15.1 ],
+        ["setCenter", [-122.448635, 37.7669995] ],
         ["wait"],
         ["addSource", "rgbterrain", {
           "type": "raster-dem",
@@ -18,6 +18,11 @@
           "tileSize": 256
         }],
         ["setTerrain", {"source": "rgbterrain"}],
+        ["wait"],
+        ["setZoom", 15.2],
+        ["wait"],
+        ["setZoom", 15],
+        ["wait"],
         ["wait"]
       ]
     }
diff --git a/test/unit/geo/transform.test.js b/test/unit/geo/transform.test.js
@@ -8,7 +8,7 @@ import {FreeCameraOptions} from '../../../src/ui/free_camera.js';
 import MercatorCoordinate, {mercatorZfromAltitude} from '../../../src/geo/mercator_coordinate.js';
 import {vec3, quat} from 'gl-matrix';
 import LngLatBounds from '../../../src/geo/lng_lat_bounds.js';
-import {degToRad} from '../../../src/util/util.js';
+import {extend, degToRad} from '../../../src/util/util.js';
 
 test('transform', (t) => {
 
@@ -529,12 +529,16 @@ test('transform', (t) => {
     });
 
     test('coveringTiles for terrain', (t) => {
-        const options = {
+        const options2D = {
             minzoom: 1,
             maxzoom: 10,
             tileSize: 512
         };
 
+        const options = extend({
+            useElevationData: true
+        }, options2D);
+
         const transform = new Transform();
         let centerElevation = 0;
         let tilesDefaultElevation = 0;
@@ -596,7 +600,7 @@ test('transform', (t) => {
         transform.center = new LngLat(56.90, 48.20);
         transform.resize(1024, 768);
         transform.elevation = null;
-        const cover2D = transform.coveringTiles(options);
+        const cover2D = transform.coveringTiles(options2D);
         // No LOD as there is no elevation data.
         t.true(cover2D[0].overscaledZ === cover2D[cover2D.length - 1].overscaledZ);
 
@@ -694,23 +698,6 @@ test('transform', (t) => {
             t.end();
         });
 
-        t.test('zoom 22 somewhere in Mile High City should load only visible tiles', (t) => {
-            tilesDefaultElevation = null;
-            centerElevation = 1600;
-            tileElevation[new OverscaledTileID(14, 0, 14, 3413, 6218).key] = 1600;
-            transform.resize(768, 768);
-            transform.zoom = options.maxzoom = 22;
-            transform.center = {lng: -104.99813327, lat: 39.72784465999999};
-            options.roundZoom = true;
-            t.deepEqual(transform.coveringTiles(options), [
-                new OverscaledTileID(22, 0, 22, 873835, 1592007),
-                new OverscaledTileID(22, 0, 22, 873834, 1592007),
-                new OverscaledTileID(22, 0, 22, 873835, 1592006),
-                new OverscaledTileID(22, 0, 22, 873834, 1592006)
-            ]);
-            t.end();
-        });
-
         t.end();
     });
 
