Fix hd-road-markup elevated lines rendering flat with

GitOrigin-RevId: 1f68535ce73c922e7d270404381e761a7af87b94

Author: mapbox-github-ci-writer-5[bot]

3d-style/source/elevation_coverage_snapshot.ts

@@ -1,4 +1,5 @@
 import {RenderSourceType} from '../../src/source/render_source_type';
+import {terrainEnabled} from '../../src/style/terrain';
 
 import type {
     ElevationCoverageSnapshot as IElevationCoverageSnapshot,
@@ -95,9 +96,8 @@ export function buildElevationRequestParams(
     crossSourceElevationEnabled: boolean,
 ): ElevationParams | null {
     if (tile.renderSourceType === RenderSourceType.HdRoadElevation) return null;
-    // Under terrain: skip snapshot — HD road-markup lines drape flat.
-    // style.terrain is synchronous; painter.terrain lags one frame.
-    if (map.style && map.style.terrain) return null;
+    // Active terrain: lines drape flat instead of using the snapshot.
+    if (terrainEnabled(map.style, map.transform)) return null;
     if (!crossSourceElevationEnabled) return null;
     const snapshot = map.painter ? map.painter.elevationCoverageSnapshot : null;
     // Defaults false (defer) until providers settle.

3d-style/style/elevation_coverage_style.ts

@@ -2,6 +2,7 @@ import {ElevationCoverageManager} from '../source/elevation_coverage_manager';
 import SourceCache from '../../src/source/source_cache';
 import {RenderSourceType} from '../../src/source/render_source_type';
 import {getNameFromFQID, getOuterScopeFromFQID, makeFQID} from '../../src/util/fqid';
+import {terrainEnabled} from '../../src/style/terrain';
 
 import type Tile from '../../src/source/tile';
 import type {TypedStyleLayer} from '../../src/style/style_layer/typed_style_layer';
@@ -44,7 +45,6 @@ function layerUsesHdRoadSourceLayer(layer: TypedStyleLayer): boolean {
 }
 
 /// True when every provider-only source has finished loading.
-/// Dual-role sources are excluded to avoid circular deferral.
 function areElevationProvidersReady(style: Style, providerFQIDs: Set<string>): boolean {
     for (const fqid of providerFQIDs) {
         const sc = resolveIngestSourceCache(style, fqid) as unknown as SourceCacheTiles | undefined;
@@ -109,7 +109,7 @@ export function collectElevationProviderSourceFQIDs(style: Style): Set<string> {
     return providers;
 }
 
-/// True when a consumer resolves elevation from a different source.
+/// True when a consumer gets elevation from a different source.
 export function needsCrossSourceElevation(style: Style): boolean {
     const consumers = collectElevationConsumerSourceFQIDs(style);
     if (consumers.size === 0) return false;
@@ -125,26 +125,19 @@ export function needsCrossSourceElevation(style: Style): boolean {
 /// Recompute the cached cross-source gate after a source change.
 export function updateCrossSourceElevationGate(style: Style): void {
     style._crossSourceElevationActive = needsCrossSourceElevation(style);
-    if (Object.keys(style._mergedHdRoadElevationSourceCaches).length === 0) return;
+    // HdElevationState only needed once dedicated elevation caches exist.
+    const hdCaches = style._mergedHdRoadElevationSourceCaches;
+    if (!hdCaches || Object.keys(hdCaches).length === 0) return;
     if (!style._hdElevation) style._hdElevation = new HdElevationState();
     style._hdElevation._needsCrossSourceElevation = style._crossSourceElevationActive;
 }
 
-/// Reparse consumer tiles after terrain on/off (flat ↔ elevated geometry).
-export function handleTerrainToggle(style: Style, hadTerrain: boolean): void {
-    if (hadTerrain === !!style.terrain) return;
-    reparseElevationConsumerTiles(style);
-}
-
 /// Cached cross-source gate; refreshed on source change and each frame.
 export function crossSourceElevationEnabledForStyle(style: Style): boolean {
     return style._crossSourceElevationActive === true;
 }
 
-/// Sources whose tiles feed the elevation snapshot (providers and dual-role).
-/// This is exactly every source with an hd_road_* source-layer: provider-only
-/// and dual-role sources together make up the full set, so no consumer/provider
-/// split is needed.
+/// Sources whose tiles are scanned to build the cross-source snapshot.
 export function collectElevationIngestSourceFQIDs(style: Style): Set<string> {
     const ingest = new Set<string>();
     for (const layerId in style._mergedLayers) {
@@ -166,16 +159,19 @@ export function markElevationIngestSourceCachesUsed(style: Style): void {
     }
 }
 
-/// Reload consumer tiles (optionally filtered). Skips non-consumers like raster-dem.
+/// Reload hd-road-markup consumer tiles.
 export function reparseElevationConsumerTiles(
     style: Style,
     shouldReload?: (tile: Tile) => boolean,
+    includeSameSourceConsumers?: boolean,
 ): void {
-    // Skip dual-role ingest sources — reparsing them causes a reload loop.
     const consumerFQIDs = collectElevationConsumerSourceFQIDs(style);
     if (consumerFQIDs.size === 0) return;
-    const ingestFQIDs = collectElevationIngestSourceFQIDs(style);
-    for (const fqid of ingestFQIDs) consumerFQIDs.delete(fqid);
+    if (!includeSameSourceConsumers) {
+        // Same-source: elevation is parsed from the consumer tile itself.
+        const ingestFQIDs = collectElevationIngestSourceFQIDs(style);
+        for (const fqid of ingestFQIDs) consumerFQIDs.delete(fqid);
+    }
     if (consumerFQIDs.size === 0) return;
 
     const caches = [style._mergedOtherSourceCaches, style._mergedSymbolSourceCaches];
@@ -200,12 +196,14 @@ export class HdElevationState {
     manager: ElevationCoverageManager;
     _needsCrossSourceElevation: boolean;
     _ingestFQIDs: Set<string>;
+    _terrainActiveLast: boolean | undefined;
 
     constructor() {
         this.elevationSourceCaches = {};
         this.manager = new ElevationCoverageManager();
         this._needsCrossSourceElevation = false;
         this._ingestFQIDs = new Set();
+        this._terrainActiveLast = undefined;
     }
 }
 
@@ -237,18 +235,27 @@ function deactivateCrossSourceElevation(style: Style): void {
     style._hdElevation._needsCrossSourceElevation = false;
     style._hdElevation._ingestFQIDs.clear();
     style._hdElevation.manager.clear();
+    style._hdElevation._terrainActiveLast = undefined;
 }
 
 /// Setup provider caches, merge fragments, ingest tiles, and reparse consumers.
 export function setupAndUpdateElevationCoverage(style: Style): void {
-    // Under terrain: skip. Use style.terrain, not painter.terrain (lags a frame). Keep gate for toggle.
-    if (style.terrain) {
-        if (style.map.painter) style.map.painter.elevationCoverageSnapshot = null;
+    if (!hasElevationConsumers(style)) {
+        deactivateCrossSourceElevation(style);
         return;
     }
 
-    if (!hasElevationConsumers(style)) {
-        deactivateCrossSourceElevation(style);
+    const terrainActive = terrainEnabled(style, style.map && style.map.transform);
+    if (!style._hdElevation) style._hdElevation = new HdElevationState();
+    const prevTerrainActive = style._hdElevation._terrainActiveLast;
+    style._hdElevation._terrainActiveLast = terrainActive;
+    const flipped = prevTerrainActive !== undefined && prevTerrainActive !== terrainActive;
+    if (flipped) {
+        reparseElevationConsumerTiles(style, undefined, true);
+    }
+
+    if (terrainActive) {
+        if (style.map.painter) style.map.painter.elevationCoverageSnapshot = null;
         return;
     }
 
@@ -258,9 +265,12 @@ export function setupAndUpdateElevationCoverage(style: Style): void {
         return;
     }
 
-    if (!style._hdElevation) {
-        style._hdElevation = new HdElevationState();
+    // First frame with cross-source active and terrain inactive: reparse consumers so they
+    // pick up elevation immediately rather than waiting for a snapshot change.
+    if (prevTerrainActive === undefined) {
+        reparseElevationConsumerTiles(style, undefined, true);
     }
+
     const state = style._hdElevation;
     state._needsCrossSourceElevation = true;
     style._crossSourceElevationActive = true;
@@ -308,8 +318,8 @@ export function updateHdElevationSourceCache(style: Style, state: HdElevationSta
 
 /// Ingest provider tiles and reparse consumers whose covering changed.
 export function updateElevationCoverage(style: Style, state: HdElevationState) {
-    // Under terrain: clear snapshot (lines drape flat).
-    if (style.terrain) {
+    // Active terrain: markup lines drape flat, no snapshot.
+    if (terrainEnabled(style, style.map && style.map.transform)) {
         state.manager.clear();
         if (style.map.painter) style.map.painter.elevationCoverageSnapshot = null;
         return;

modules/hd_main_imports.ts

@@ -8,7 +8,7 @@ import {Snow} from '../src/precipitation/draw_snow';
 import {programUniforms} from '../3d-style/render/program/program_uniforms_hd';
 import {drawElevatedStructures, drawElevatedFillShadows, drawDepthPrepass, drawGroundShadowMask} from '../3d-style/render/draw_elevated_fill';
 import {HdCoverageState, updateFrcCoverage, updateHdCoverageSourceCache, updateFrcCoverageFadeRange} from '../3d-style/style/frc_coverage_style';
-import {HdElevationState, setupAndUpdateElevationCoverage, updateElevationCoverage, updateHdElevationSourceCache, markElevationIngestSourceCachesUsed, updateCrossSourceElevationGate, handleTerrainToggle} from '../3d-style/style/elevation_coverage_style';
+import {HdElevationState, setupAndUpdateElevationCoverage, updateElevationCoverage, updateHdElevationSourceCache, markElevationIngestSourceCachesUsed, updateCrossSourceElevationGate} from '../3d-style/style/elevation_coverage_style';
 import {buildElevationRequestParams} from '../3d-style/source/elevation_coverage_snapshot';
 import {FrcCoverageRenderer} from '../3d-style/render/frc_coverage_renderer';
 import {
@@ -57,7 +57,6 @@ export const HD = {
     updateHdElevationSourceCache,
     markElevationIngestSourceCachesUsed,
     updateCrossSourceElevationGate,
-    handleTerrainToggle,
     buildElevationRequestParams,
     FrcCoverageRenderer,
     drawFillFrcCoverageFirstPass,

src/source/vector_tile_source.ts

@@ -11,6 +11,7 @@ import {makeFQID} from '../util/fqid';
 import {isMapboxURL} from '../util/mapbox_url';
 import {resolveTileProvider, processTileJSON} from './tile_provider';
 import {HD, prepareHD} from '../../modules/hd_main';
+import {terrainEnabled} from '../style/terrain';
 import {Standard, prepareStandard} from '../../modules/standard_main';
 
 import type {ISource, SourceEvents, SourceVectorLayer} from './source';
@@ -141,6 +142,7 @@ class VectorTileSource extends Evented<SourceEvents> implements ISource<'vector'
                 this.fire(new ErrorEvent(err));
             } else if (tileJSON) {
                 this._setTileJSON(tileJSON);
+                if (HD.updateCrossSourceElevationGate && this.map.style) HD.updateCrossSourceElevationGate(this.map.style);
                 postTurnstileEvent(tileJSON.tiles, this.map._requestManager._customAccessToken);
                 // `content` is included here to prevent a race condition where `Style#updateSources` is called
                 // before the TileJSON arrives. this makes sure the tiles needed are loaded once TileJSON arrives
@@ -388,8 +390,7 @@ class VectorTileSource extends Evented<SourceEvents> implements ISource<'vector'
                     sourceLayers: painter ? painter.frcCoverageSourceLayers : ['road', 'structure'],
                 };
             })(),
-            // style.terrain is synchronous; painter.terrain lags one frame.
-            terrainEnabled: !!(this.map.style && this.map.style.terrain),
+            terrainEnabled: terrainEnabled(this.map.style, this.map.transform),
             crossSourceElevationEnabled,
             elevation: HD.buildElevationRequestParams ?
                 HD.buildElevationRequestParams(this.map, tile, crossSourceElevationActive) : null,

src/style/style.ts

@@ -3991,10 +3991,6 @@ class Style extends Evented<MapEvents> {
     setTerrain(terrainOptions?: TerrainSpecification | TerrainSpecificationUpdate | null, drapeRenderMode: number = DrapeRenderMode.elevated) {
         this._checkLoaded();
 
-        // Terrain on/off must reparse HD road-markup tiles. setTerrain(null) on a draping
-        // projection re-adds draping terrain, so !!terrain stays true → no reparse (correct).
-        const hadTerrain = !!this.terrain;
-
         // Disabling
         if (!terrainOptions) {
             // This check prevents removing draping terrain not from #applyProjectionUpdate
@@ -4018,7 +4014,6 @@ class Style extends Evented<MapEvents> {
 
             this._force3DLayerUpdate();
             this._markersNeedUpdate = true;
-            if (HD.handleTerrainToggle) HD.handleTerrainToggle(this, hadTerrain);
             return;
         }
 
@@ -4087,7 +4082,6 @@ class Style extends Evented<MapEvents> {
         this.mergeTerrain();
         this.updateDrapeFirstLayers();
         this._markersNeedUpdate = true;
-        if (HD.handleTerrainToggle) HD.handleTerrainToggle(this, hadTerrain);
     }
 
     _createFog(fogOptions: FogSpecification) {

src/style/terrain.ts

@@ -118,3 +118,17 @@ class Terrain extends Evented {
 }
 
 export default Terrain;
+
+/// True when terrain is enabled at the current zoom.
+/// Zero exaggeration on zoom-dependent terrain counts as disabled.
+export function terrainEnabled(
+    style: {terrain?: Terrain | null} | null | undefined,
+    transform: {zoom: number; projection: {requiresDraping: boolean}} | null | undefined,
+): boolean {
+    const terrain = style ? style.terrain : null;
+    if (!terrain) return false;
+    if (!transform) return true; // conservative: can't evaluate exaggeration, assume active
+    if (transform.projection.requiresDraping) return true;
+    if (!terrain.isZoomDependent()) return true;
+    return terrain.getExaggeration(transform.zoom) > 0;
+}