From e734242cd2265fbd77b2d0a998a4cbc33fa4d0c3 Mon Sep 17 00:00:00 2001
From: andremig-bentley <101671244+andremig-bentley@users.noreply.github.com>
Date: Mon, 21 Oct 2024 15:54:19 -0600
Subject: [PATCH] Add Undefined mercatorOrigin Check to
 computeMercatorFractionToDb (#7269)

Co-authored-by: andremig-bentley <andremig-bentley@users.noreply.github.com>
Co-authored-by: Paul Connelly <22944042+pmconne@users.noreply.github.com>
(cherry picked from commit a05e3b6aa83db16717f699fee40290f7619acd79)
---
 .../andremig-map_2024-10-15-19-56.json           | 10 ++++++++++
 .../src/test/BackgroundMapGeometry.test.ts       | 16 ++++++++++++++--
 core/frontend/src/tile/map/MapTilingScheme.ts    |  9 +++++++--
 3 files changed, 31 insertions(+), 4 deletions(-)
 create mode 100644 common/changes/@itwin/core-frontend/andremig-map_2024-10-15-19-56.json

diff --git a/common/changes/@itwin/core-frontend/andremig-map_2024-10-15-19-56.json b/common/changes/@itwin/core-frontend/andremig-map_2024-10-15-19-56.json
new file mode 100644
index 000000000000..ac11a63efe7e
--- /dev/null
+++ b/common/changes/@itwin/core-frontend/andremig-map_2024-10-15-19-56.json
@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@itwin/core-frontend",
+      "comment": "",
+      "type": "none"
+    }
+  ],
+  "packageName": "@itwin/core-frontend"
+}
\ No newline at end of file
diff --git a/core/frontend/src/test/BackgroundMapGeometry.test.ts b/core/frontend/src/test/BackgroundMapGeometry.test.ts
index f647ca8443db..0055583c4fe2 100644
--- a/core/frontend/src/test/BackgroundMapGeometry.test.ts
+++ b/core/frontend/src/test/BackgroundMapGeometry.test.ts
@@ -7,10 +7,11 @@ import { expect } from "chai";
 import sinon from "sinon";
 import { IModelApp } from "../IModelApp";
 import { Cartographic, EmptyLocalization, GlobeMode } from "@itwin/core-common";
-import { IModelConnection } from "../IModelConnection";
-import { Range3d, XYAndZ } from "@itwin/core-geometry";
+import { BlankConnection, IModelConnection } from "../IModelConnection";
+import { Point3d, Range3d, XYAndZ } from "@itwin/core-geometry";
 import { BackgroundMapGeometry } from "../BackgroundMapGeometry";
 import { createBlankConnection } from "./createBlankConnection";
+import { Guid } from "@itwin/core-bentley";
 
 describe("BackgroundMapGeometry", () => {
   const sandbox = sinon.createSandbox();
@@ -53,4 +54,15 @@ describe("BackgroundMapGeometry", () => {
       expect(dataset[i].z).to.eq(result[i].height);
     }
   });
+
+  it("creates new background map geometry when the origin is (0, 0, 0)", async () => {
+    const name = "test-blank-connection";
+    const extents = new Range3d(-2500, -2500, -1000, 2500, 2500, 1000);
+    const globalOrigin = new Point3d(0, 0, 0);
+    const iTwinId = Guid.createValue();
+    const imodel = BlankConnection.create({ name, location: { origin: [0, 0, 0], orientation: { yaw: 0, pitch: 0, roll: 0 } }, extents, iTwinId, globalOrigin });
+
+    const geometry = new BackgroundMapGeometry(0, 0, imodel);
+    expect(geometry).to.not.be.undefined;
+  });
 });
diff --git a/core/frontend/src/tile/map/MapTilingScheme.ts b/core/frontend/src/tile/map/MapTilingScheme.ts
index 6ee2f3d59686..9d64caf4b247 100644
--- a/core/frontend/src/tile/map/MapTilingScheme.ts
+++ b/core/frontend/src/tile/map/MapTilingScheme.ts
@@ -188,8 +188,10 @@ export abstract class MapTilingScheme {
   }
 
   /** @alpha */
-  private ecefToPixelFraction(point: Point3d, applyTerrain: boolean): Point3d {
-    const cartoGraphic = Cartographic.fromEcef(point)!;
+  private ecefToPixelFraction(point: Point3d, applyTerrain: boolean): Point3d | undefined {
+    const cartoGraphic = Cartographic.fromEcef(point);
+    if (!cartoGraphic)
+      return undefined;
     return Point3d.create(this.longitudeToXFraction(cartoGraphic.longitude), this.latitudeToYFraction(cartoGraphic.latitude), applyTerrain ? cartoGraphic.height : 0);
   }
 
@@ -205,6 +207,9 @@ export abstract class MapTilingScheme {
     const mercatorX = this.ecefToPixelFraction(dbToEcef.multiplyPoint3d(projectEast), applyTerrain);
     const mercatorY = this.ecefToPixelFraction(dbToEcef.multiplyPoint3d(projectNorth), applyTerrain);
 
+    if (!mercatorOrigin || !mercatorX || !mercatorY)
+      return Transform.createIdentity();
+
     const deltaX = Vector3d.createStartEnd(mercatorOrigin, mercatorX);
     const deltaY = Vector3d.createStartEnd(mercatorOrigin, mercatorY);
     const matrix = Matrix3d.createColumns(deltaX, deltaY, Vector3d.create(0, 0, 1));