fix(geom-isec): fix #84, update pointInSegment, add tests

thi-ng · May 22, 2019 · 2bef312 · 2bef312
1 parent 40a8bff
commit 2bef312
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diff --git a/packages/geom-isec/src/point.ts b/packages/geom-isec/src/point.ts
@@ -1,23 +1,24 @@
-import { EPS, sign } from "@thi.ng/math";
+import { closestT } from "@thi.ng/geom-closest-point";
+import { clamp01, EPS, sign } from "@thi.ng/math";
 import {
     clockwise2,
     distSq,
     magSq,
+    mixN,
     ReadonlyVec,
     signedArea2
 } from "@thi.ng/vectors";
 
-export const pointInSegment2 = (
+export const pointInSegment = (
     p: ReadonlyVec,
     a: ReadonlyVec,
     b: ReadonlyVec,
     eps = EPS
 ) => {
-    const ax = a[0];
-    const ay = a[1];
-    const tx = (p[0] - ax) / (b[0] - ax);
-    const ty = (p[1] - ay) / (b[1] - ay);
-    return Math.abs(tx - ty) <= eps && !(tx < 0 || tx > 1 || ty < 0 || ty > 1);
+    const t = closestT(p, a, b);
+    return t !== undefined
+        ? distSq(p, mixN([], a, b, clamp01(t))) < eps * eps
+        : false;
 };
 
 export const pointInCircle = (p: ReadonlyVec, pos: ReadonlyVec, r: number) =>

diff --git a/packages/geom-isec/test/index.ts b/packages/geom-isec/test/index.ts
diff --git a/packages/geom-isec/test/point-segment.ts b/packages/geom-isec/test/point-segment.ts
@@ -0,0 +1,30 @@
+import * as assert from "assert";
+import { pointInSegment } from "../src";
+
+describe("pointInSegment", () => {
+    it("2d", () => {
+        assert(pointInSegment([0, 0], [-10, -10], [10, 10]), "1");
+        assert(pointInSegment([-5, -5], [-10, -10], [10, 10]), "2");
+        assert(pointInSegment([5, 5], [-10, -10], [10, 10]), "3");
+        assert(!pointInSegment([5, 5.01], [-10, -10], [10, 10]), "4");
+        assert(pointInSegment([5, 5.01], [-10, -10], [10, 10], 0.01), "4.1");
+        assert(pointInSegment([5, 4.99], [-10, -10], [10, 10], 0.01), "4.2");
+        assert(!pointInSegment([5, 5.02], [-10, -10], [10, 10], 0.01), "4.3");
+        assert(!pointInSegment([5, 4.98], [-10, -10], [10, 10], 0.01), "4.4");
+    });
+
+    it("2d axis aligned", () => {
+        assert(pointInSegment([9, 10], [5, 10], [10, 10]), "1");
+        assert(pointInSegment([9, 10], [10, 10], [5, 10]), "1.1");
+        assert(pointInSegment([10, 9], [10, 5], [10, 10]), "2");
+        assert(pointInSegment([10, 9], [10, 10], [10, 5]), "2.1");
+        assert(pointInSegment([4.9, 10], [5, 10], [10, 10], 0.1), "3");
+        assert(!pointInSegment([4.89, 10], [5, 10], [10, 10], 0.1), "3.1");
+        assert(pointInSegment([10.1, 10], [5, 10], [10, 10], 0.1), "3.2");
+        assert(!pointInSegment([10.11, 10], [5, 10], [10, 10], 0.1), "3.3");
+        assert(pointInSegment([9, 10.1], [5, 10], [10, 10], 0.1), "4");
+        assert(!pointInSegment([9, 10.11], [5, 10], [10, 10], 0.1), "4.1");
+        assert(pointInSegment([9, 9.9], [5, 10], [10, 10], 0.1), "4.2");
+        assert(!pointInSegment([9, 9.89], [5, 10], [10, 10], 0.1), "4.3");
+    });
+});