fix extrusion querying for polygons with coincident points

src/style/style_layer/fill_extrusion_style_layer.js

@@ -67,7 +67,7 @@ function dot(a, b) {
  return a.x * b.x + a.y * b.y;
 }
 
-function getIntersectionDistance(projectedQueryGeometry: Array<Point>, projectedFace: Array<Point>) {
+export function getIntersectionDistance(projectedQueryGeometry: Array<Point>, projectedFace: Array<Point>) {
 
  if (projectedQueryGeometry.length === 1) {
  // For point queries calculate the z at which the point intersects the face
@@ -77,9 +77,20 @@ function getIntersectionDistance(projectedQueryGeometry: Array<Point>, projected
  // triangle of the face, using only the xy plane. It doesn't matter if the
  // point is outside the first triangle because all the triangles in the face
  // are in the same plane.
- const a = projectedFace[0];
- const b = projectedFace[1];
- const c = projectedFace[3];
+ //
+ // Check whether points are coincident and use other points if they are.
+ let i = 0;
+ const a = projectedFace[i++];
+ let b, c;
+ while (!b || a.equals(b)) {
+ b = projectedFace[i++];
+ if (!b) return Infinity;
+ }
+ while (!c || a.equals(c) || b.equals(c)) {
+ c = projectedFace[i++];
+ if (!c) return Infinity;
+ }
+
  const p = projectedQueryGeometry[0];
 
  const ab = b.sub(a);

test/integration/query-tests/regressions/mapbox-gl-js#8999/expected.json

@@ -0,0 +1,33 @@
+[
+ {
+ "geometry": {
+ "type": "Polygon",
+ "coordinates": [
+ [
+ [
+ -19.9951171875,
+ -40.01078714046552
+ ],
+ [
+ -19.9951171875,
+ 40.01078714046551
+ ],
+ [
+ 39.990234375,
+ 40.01078714046551
+ ],
+ [
+ -19.9951171875,
+ -40.01078714046552
+ ]
+ ]
+ ]
+ },
+ "type": "Feature",
+ "properties": {
+ "layer": "extrusion_three_points"
+ },
+ "source": "extrusion_three_points",
+ "state": {}
+ }
+]

test/integration/query-tests/regressions/mapbox-gl-js#8999/style.json

@@ -0,0 +1,65 @@
+{
+ "version": 8,
+ "metadata": {
+ "test": {
+ "debug": true,
+ "width": 200,
+ "height": 200,
+ "queryGeometry": [
+ 100,
+ 40
+ ]
+ }
+ },
+ "pitch": 0,
+ "center": [
+ 0,
+ 0
+ ],
+ "zoom": 0,
+ "sources": {
+ "extrusion_three_points": {
+ "type": "geojson",
+ "data": {
+ "type": "Feature",
+ "properties": {
+ "layer": "extrusion_three_points"
+ },
+ "geometry": {
+ "type": "Polygon",
+ "coordinates": [
+ [
+ [
+ -20,
+ -40
+ ],
+ [
+ -20,
+ 40
+ ],
+ [
+ 40,
+ 40
+ ],
+ [
+ -20,
+ -40
+ ]
+ ]
+ ]
+ }
+ }
+ }
+ },
+ "layers": [
+ {
+ "id": "extrusion_three_points",
+ "type": "fill-extrusion",
+ "source": "extrusion_three_points",
+ "paint": {
+ "fill-extrusion-color": "#ecc",
+ "fill-extrusion-height": 0
+ }
+ }
+ ]
+}

test/unit/style/style_layer/fill_extrusion_style_layer.js

@@ -0,0 +1,45 @@
+import {test} from '../../../util/test';
+import {getIntersectionDistance} from '../../../../src/style/style_layer/fill_extrusion_style_layer';
+import Point from '@mapbox/point-geometry';
+
+test('getIntersectionDistance', (t) => {
+ const queryPoint = [new Point(100, 100)];
+ const z = 3;
+ const a = new Point(100, -90);
+ const b = new Point(110, 110);
+ const c = new Point(-110, 110);
+ a.z = z;
+ b.z = z;
+ c.z = z;
+
+ t.test('one point', (t) => {
+ const projectedFace = [a, a];
+ t.equal(getIntersectionDistance(queryPoint, projectedFace), Infinity);
+ t.end();
+ });
+
+ t.test('two points', (t) => {
+ const projectedFace = [a, b, a];
+ t.equal(getIntersectionDistance(queryPoint, projectedFace), Infinity);
+ t.end();
+ });
+
+ t.test('two points coincident', (t) => {
+ const projectedFace = [a, a, a, b, b, b, b, a];
+ t.equal(getIntersectionDistance(queryPoint, projectedFace), Infinity);
+ t.end();
+ });
+
+ t.test('three points', (t) => {
+ const projectedFace = [a, b, c, a];
+ t.equal(getIntersectionDistance(queryPoint, projectedFace), z);
+ t.end();
+ });
+
+ t.test('three points coincident points', (t) => {
+ const projectedFace = [a, a, b, b, b, c, c, a];
+ t.equal(getIntersectionDistance(queryPoint, projectedFace), z);
+ t.end();
+ });
+ t.end();
+});