HARP-14553: Ignore small distance differences when sorting pick results.

Intersection distances returned for 2D features on the sample plane may differ by small values (~1e-6 in world distance). Ignore those small difference and take into account only render order in those cases. Signed-off-by: Andres Mandado <[email protected]>
heremaps · Apr 27, 2021 · 943588e · 943588e
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commit 943588e
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diff --git a/@here/harp-mapview/lib/PickListener.ts b/@here/harp-mapview/lib/PickListener.ts
@@ -11,9 +11,12 @@ import { PickResult } from "./PickHandler";
 
 // Default sorting by distance first and then by reversed render order.
 function defaultSort(lhs: PickResult, rhs: PickResult) {
+    // HARP-14553: Set a distance tolerance to ignore small distance differences between 2D objects
+    // that are supposed to lie on the same plane.
+    const eps = 1e-4;
     const distanceDiff = lhs.distance - rhs.distance;
     const haveRenderOrder = lhs.renderOrder !== undefined && rhs.renderOrder !== undefined;
-    if (distanceDiff !== 0 || !haveRenderOrder) {
+    if (Math.abs(distanceDiff) > eps || !haveRenderOrder) {
         return distanceDiff;
     }
 

diff --git a/@here/harp-mapview/test/PickListenerTest.ts b/@here/harp-mapview/test/PickListenerTest.ts
@@ -207,6 +207,32 @@ describe("PickListener", function () {
             expect(listener.results).to.have.ordered.members(expectedResults);
         });
 
+        it("ignores small distance differences for sorting", function () {
+            const listener = new PickListener();
+            const eps = 1e-6;
+            const expectedResults: PickResult[] = [
+                {
+                    type: PickObjectType.Point,
+                    point,
+                    distance: eps,
+                    renderOrder: 2,
+                    dataSourceName
+                },
+                {
+                    type: PickObjectType.Point,
+                    point,
+                    distance: 0,
+                    renderOrder: 1,
+                    dataSourceName
+                }
+            ];
+            listener.addResult(expectedResults[1]);
+            listener.addResult(expectedResults[0]);
+            listener.finish();
+
+            expect(listener.results).to.have.ordered.members(expectedResults);
+        });
+
         it("keeps only the closest maximum result count if specified", function () {
             const maxResultCount = 1;
             const listener = new PickListener({ maxResultCount });