HARP-13329: Move ground plane generation out of TileGeometryCreator.

Add unit tests for ground plane generation.

@here/harp-mapview/lib/BackgroundDataSource.ts

@@ -8,7 +8,7 @@ import { FlatTheme, Theme } from "@here/harp-datasource-protocol";
 import { TileKey, TilingScheme, webMercatorTilingScheme } from "@here/harp-geoutils";
 
 import { DataSource } from "./DataSource";
-import { TileGeometryCreator } from "./geometry/TileGeometryCreator";
+import { addGroundPlane } from "./geometry/AddGroundPlane";
 import { Tile } from "./Tile";
 
 /**
@@ -77,7 +77,7 @@ export class BackgroundDataSource extends DataSource {
     getTile(tileKey: TileKey): Tile | undefined {
         const tile = new Tile(this, tileKey);
         tile.forceHasGeometry(true);
-        TileGeometryCreator.instance.addGroundPlane(tile, BackgroundDataSource.GROUND_RENDER_ORDER);
+        addGroundPlane(tile, BackgroundDataSource.GROUND_RENDER_ORDER);
 
         return tile;
     }

@here/harp-mapview/lib/geometry/AddGroundPlane.ts

@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2017-2020 HERE Europe B.V.
+ * Licensed under Apache 2.0, see full license in LICENSE
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { GeometryKind } from "@here/harp-datasource-protocol";
+import {
+    EdgeLengthGeometrySubdivisionModifier,
+    SubdivisionMode
+} from "@here/harp-geometry/lib/EdgeLengthGeometrySubdivisionModifier";
+import { SphericalGeometrySubdivisionModifier } from "@here/harp-geometry/lib/SphericalGeometrySubdivisionModifier";
+import { Projection, ProjectionType } from "@here/harp-geoutils";
+import { MapMeshBasicMaterial, MapMeshStandardMaterial } from "@here/harp-materials";
+import * as THREE from "three";
+
+import { Tile } from "../Tile";
+import { LodMesh } from "./LodMesh";
+import { projectTilePlaneCorners } from "./ProjectTilePlaneCorners";
+import { registerTileObject } from "./RegisterTileObject";
+
+const tmpV = new THREE.Vector3();
+
+/**
+ * Creates and adds a background plane mesh for the tile.
+ * @param tile - The tile to which the ground plane belongs.
+ * @param renderOrder - The plane render order.
+ * @param materialOrColor - The plane material or a color for a default material.
+ * @param createTexCoords - Whether to create texture coordinates.
+ * @param receiveShadow - Whether the plane should receive shadows.
+ * @param createMultiLod - Whether to generate multiple LODs for sphere projection.
+ * @internal
+ */
+export function addGroundPlane(
+    tile: Tile,
+    renderOrder: number,
+    materialOrColor: THREE.Material | THREE.Material[] | number = tile.mapView.clearColor,
+    createTexCoords: boolean = false,
+    receiveShadow: boolean = tile.mapView.shadowsEnabled,
+    createMultiLod: boolean = tile.mapView.enableMixedLod !== false
+) {
+    const mesh = createGroundPlane(
+        tile,
+        createTexCoords,
+        receiveShadow,
+        materialOrColor,
+        createMultiLod
+    );
+    mesh.receiveShadow = receiveShadow;
+    mesh.renderOrder = renderOrder;
+    registerTileObject(tile, mesh, GeometryKind.Background, { pickable: false });
+    tile.objects.push(mesh);
+}
+
+function createGroundPlane(
+    tile: Tile,
+    createTexCoords: boolean,
+    receiveShadow: boolean,
+    materialOrColor: THREE.Material | THREE.Material[] | number,
+    createMultiLod: boolean
+): THREE.Mesh {
+    const { dataSource, projection } = tile;
+    const sourceProjection = dataSource.getTilingScheme().projection;
+    const shouldSubdivide = projection.type === ProjectionType.Spherical;
+    const useLocalTargetCoords = !shouldSubdivide;
+
+    const material =
+        typeof materialOrColor === "number"
+            ? createGroundPlaneMaterial(
+                  new THREE.Color(materialOrColor),
+                  receiveShadow,
+                  projection.type === ProjectionType.Spherical
+              )
+            : materialOrColor;
+
+    const geometry = createGroundPlaneGeometry(
+        tile,
+        useLocalTargetCoords,
+        createTexCoords,
+        receiveShadow
+    );
+
+    if (!shouldSubdivide) {
+        return new THREE.Mesh(geometry, material);
+    }
+
+    const geometries: THREE.BufferGeometry[] = [];
+    const sphericalModifier = new SphericalGeometrySubdivisionModifier(
+        THREE.MathUtils.degToRad(10),
+        sourceProjection
+    );
+
+    if (!createMultiLod) {
+        sphericalModifier.modify(geometry);
+        toLocalTargetCoords(geometry, sourceProjection, tile);
+
+        return new THREE.Mesh(geometry, material);
+    }
+
+    // Use a [[LodMesh]] to adapt tesselation of tile depending on zoom level
+    for (let zoomLevelOffset = 0; zoomLevelOffset < 4; ++zoomLevelOffset) {
+        const subdivision = Math.pow(2, zoomLevelOffset);
+        const zoomLevelGeometry = geometry.clone();
+        if (subdivision > 1) {
+            const edgeModifier = new EdgeLengthGeometrySubdivisionModifier(
+                subdivision,
+                tile.geoBox,
+                SubdivisionMode.All,
+                sourceProjection
+            );
+            edgeModifier.modify(zoomLevelGeometry);
+        }
+        sphericalModifier.modify(zoomLevelGeometry);
+        toLocalTargetCoords(zoomLevelGeometry, sourceProjection, tile);
+        geometries.push(zoomLevelGeometry);
+    }
+    return new LodMesh(geometries, material);
+}
+
+function toLocalTargetCoords(geom: THREE.BufferGeometry, srcProjection: Projection, tile: Tile) {
+    const attr = geom.getAttribute("position") as THREE.BufferAttribute;
+    const oldArray = attr.array as Float64Array;
+    // Convert to single precision before rendering (WebGL does not support double
+    // precision).
+    const newArray = new Float32Array(oldArray.length);
+    for (let i = 0; i < attr.array.length; i += 1) {
+        tmpV.fromBufferAttribute(attr, i);
+        tile.projection.reprojectPoint(srcProjection, tmpV, tmpV).sub(tile.center);
+        tmpV.toArray(newArray, i * 3);
+    }
+    attr.array = newArray;
+    attr.needsUpdate = true;
+}
+
+function createGroundPlaneGeometry(
+    tile: Tile,
+    useLocalTargetCoords: boolean,
+    createTexCoords: boolean,
+    receiveShadow: boolean
+): THREE.BufferGeometry {
+    const { dataSource, projection } = tile;
+    const sourceProjection = dataSource.getTilingScheme().projection;
+    const tmpV = new THREE.Vector3();
+
+    const geometry = new THREE.BufferGeometry();
+    const tileCorners = projectTilePlaneCorners(tile, sourceProjection);
+    const cornersArray = [tileCorners.sw, tileCorners.se, tileCorners.nw, tileCorners.ne];
+    if (useLocalTargetCoords) {
+        for (const corner of cornersArray) {
+            projection.reprojectPoint(sourceProjection, corner, corner).sub(tile.center);
+        }
+    }
+    // Use 64bits floats for world coordinates to avoid precision issues on coordinate
+    // tranformations. The array must be converted to single precision before rendering.
+    const bufferArray = useLocalTargetCoords ? new Float32Array(12) : new Float64Array(12);
+    const posAttr = new THREE.BufferAttribute(bufferArray, 3).copyVector3sArray(cornersArray);
+    geometry.setAttribute("position", posAttr);
+
+    if (receiveShadow) {
+        // Webmercator needs to have it negated to work correctly.
+        sourceProjection.surfaceNormal(tileCorners.sw, tmpV).negate();
+        const normAttr = new THREE.BufferAttribute(new Float32Array(12), 3).copyVector3sArray(
+            Array(4).fill(tmpV)
+        );
+        geometry.setAttribute("normal", normAttr);
+    }
+    geometry.setIndex(new THREE.BufferAttribute(new Uint16Array([0, 1, 2, 2, 1, 3]), 1));
+
+    if (createTexCoords) {
+        const uvAttr = new THREE.BufferAttribute(new Float32Array([0, 0, 1, 0, 0, 1, 1, 1]), 2);
+        geometry.setAttribute("uv", uvAttr);
+    }
+
+    return geometry;
+}
+
+function createGroundPlaneMaterial(
+    color: THREE.Color,
+    receiveShadow: boolean,
+    depthWrite: boolean
+): THREE.Material {
+    if (receiveShadow) {
+        return new MapMeshStandardMaterial({
+            color,
+            visible: true,
+            depthWrite,
+            removeDiffuseLight: true
+        });
+    } else {
+        return new MapMeshBasicMaterial({
+            color,
+            visible: true,
+            depthWrite
+        });
+    }
+}

@here/harp-mapview/lib/geometry/RegisterTileObject.ts

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2017-2020 HERE Europe B.V.
+ * Licensed under Apache 2.0, see full license in LICENSE
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { GeometryKind, GeometryKindSet } from "@here/harp-datasource-protocol";
+import * as THREE from "three";
+
+import { MapObjectAdapter, MapObjectAdapterParams } from "../MapObjectAdapter";
+import { Tile } from "../Tile";
+
+/**
+ * Adds a THREE object to the root of the tile and register [[MapObjectAdapter]].
+ *
+ * Sets the owning tiles datasource.name and the `tileKey` in the `userData` property of the
+ * object, such that the tile it belongs to can be identified during picking.
+ *
+ * @param tile - The {@link Tile} to add the object to.
+ * @param object - The object to add to the root of the tile.
+ * @param geometryKind - The kind of object. Can be used for filtering.
+ * @param mapAdapterParams - additional parameters for [[MapObjectAdapter]]
+ */
+export function registerTileObject(
+    tile: Tile,
+    object: THREE.Object3D,
+    geometryKind: GeometryKind | GeometryKindSet | undefined,
+    mapAdapterParams?: MapObjectAdapterParams
+) {
+    const kind =
+        geometryKind instanceof Set
+            ? Array.from((geometryKind as GeometryKindSet).values())
+            : Array.isArray(geometryKind)
+            ? geometryKind
+            : [geometryKind];
+
+    MapObjectAdapter.create(object, {
+        dataSource: tile.dataSource,
+        kind,
+        level: tile.tileKey.level,
+        ...mapAdapterParams
+    });
+
+    // TODO legacy fields, encoded directly in `userData to be removed
+    if (object.userData === undefined) {
+        object.userData = {};
+    }
+
+    const userData = object.userData;
+    userData.tileKey = tile.tileKey;
+    userData.dataSource = tile.dataSource.name;
+
+    userData.kind = kind;
+
+    // Force a visibility check of all objects.
+    tile.resetVisibilityCounter();
+}