Add segment class and utilities.

source/engine/geometry/coord2d.js

@@ -33,3 +33,8 @@ export function CoordDistance2D (a, b)
 {
 	return Math.sqrt ((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
 }
+
+export function DotVector2D (a, b)
+{
+	return a.x * b.x + a.y * b.y;
+}

source/engine/geometry/line2d.js

@@ -0,0 +1,39 @@
+import { Coord2D, CoordDistance2D, DotVector2D, SubCoord2D } from './coord2d.js';
+import { IsZero } from './geometry.js';
+
+export class Segment2D
+{
+	constructor (beg, end)
+	{
+		this.beg = beg;
+		this.end = end;
+	}
+
+	Clone ()
+	{
+		return new Segment2D (this.beg, this.end);
+	}
+}
+
+export function ProjectPointToSegment2D (segment, point)
+{
+    let begToEndVec = SubCoord2D (segment.end, segment.beg);
+    let begToPointVec = SubCoord2D (point, segment.beg);
+    let nom = DotVector2D (begToEndVec, begToPointVec);
+    let denom = DotVector2D (begToEndVec, begToEndVec);
+    if (IsZero (denom)) {
+        return segment.beg.Clone ();
+    }
+    let t = nom / denom;
+    t = Math.max (0.0, Math.min (1.0, t));
+    return new Coord2D (
+        segment.beg.x + t * begToEndVec.x,
+        segment.beg.y + t * begToEndVec.y
+    );
+}
+
+export function SegmentPointDistance2D (segment, point)
+{
+    let projected = ProjectPointToSegment2D (segment, point);
+    return CoordDistance2D (projected, point);
+}

source/engine/main.js

@@ -12,10 +12,11 @@ import { ExporterOff } from './export/exporteroff.js';
 import { ExporterPly } from './export/exporterply.js';
 import { ExporterStl } from './export/exporterstl.js';
 import { Box3D, BoundingBoxCalculator3D } from './geometry/box3d.js';
-import { Coord2D, CoordIsEqual2D, AddCoord2D, SubCoord2D, CoordDistance2D } from './geometry/coord2d.js';
+import { Coord2D, CoordIsEqual2D, AddCoord2D, SubCoord2D, CoordDistance2D, DotVector2D } from './geometry/coord2d.js';
 import { Coord3D, CoordIsEqual3D, AddCoord3D, SubCoord3D, CoordDistance3D, DotVector3D, VectorAngle3D, CrossVector3D, VectorLength3D, ArrayToCoord3D } from './geometry/coord3d.js';
 import { Coord4D } from './geometry/coord4d.js';
 import { IsZero, IsLower, IsGreater, IsLowerOrEqual, IsGreaterOrEqual, IsEqual, IsEqualEps, IsPositive, IsNegative, Eps, BigEps, RadDeg, DegRad, Direction } from './geometry/geometry.js';
+import { Segment2D, ProjectPointToSegment2D, SegmentPointDistance2D } from './geometry/line2d.js';
 import { Matrix, MatrixIsEqual } from './geometry/matrix.js';
 import { OctreeNode, Octree } from './geometry/octree.js';
 import { Quaternion, QuaternionIsEqual, ArrayToQuaternion, QuaternionFromAxisAngle, QuaternionFromXYZ } from './geometry/quaternion.js';
@@ -105,6 +106,7 @@ export {
     AddCoord2D,
     SubCoord2D,
     CoordDistance2D,
+    DotVector2D,
     Coord3D,
     CoordIsEqual3D,
     AddCoord3D,
@@ -130,6 +132,9 @@ export {
     RadDeg,
     DegRad,
     Direction,
+    Segment2D,
+    ProjectPointToSegment2D,
+    SegmentPointDistance2D,
     Matrix,
     MatrixIsEqual,
     OctreeNode,

test/tests/geometry_test.js

@@ -63,6 +63,62 @@ describe ('Coord', function () {
     });
 });
 
+describe ('Segment', function () {
+    it ('Projected point', function () {
+        let segment = new OV.Segment2D (new OV.Coord2D (0.0, 0.0), new OV.Coord2D (10.0, 0.0));
+
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (-2.0, 0.0)), new OV.Coord2D (0.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (0.0, 0.0)), new OV.Coord2D (0.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (2.0, 0.0)), new OV.Coord2D (2.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (8.0, 0.0)), new OV.Coord2D (8.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (10.0, 0.0)), new OV.Coord2D (10.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (12.0, 0.0)), new OV.Coord2D (10.0, 0.0)));
+
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (-2.0, 10.0)), new OV.Coord2D (0.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (0.0, 10.0)), new OV.Coord2D (0.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (2.0, 10.0)), new OV.Coord2D (2.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (8.0, 10.0)), new OV.Coord2D (8.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (10.0, 10.0)), new OV.Coord2D (10.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (12.0, 10.0)), new OV.Coord2D (10.0, 0.0)));
+    });
+
+    it ('Projected point on invalid segment', function () {
+        let segment = new OV.Segment2D (new OV.Coord2D (0.0, 0.0), new OV.Coord2D (0.0, 0.0));
+
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (0.0, 0.0)), new OV.Coord2D (0.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (10.0, 0.0)), new OV.Coord2D (0.0, 0.0)));
+        assert.ok (OV.CoordIsEqual2D (OV.ProjectPointToSegment2D (segment, new OV.Coord2D (0.0, 10.0)), new OV.Coord2D (0.0, 0.0)));
+    });
+
+    it ('Segment and point distance', function () {
+        let segment = new OV.Segment2D (new OV.Coord2D (0.0, 0.0), new OV.Coord2D (0.0, 10.0));
+
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (0.0, 0.0)), 0.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (0.0, 2.0)), 0.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (0.0, 8.0)), 0.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (0.0, 10.0)), 0.0));
+
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (-2.0, 0.0)), 2.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (-4.0, 2.0)), 4.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (6.0, 8.0)), 6.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (8.0, 10.0)), 8.0));
+
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (0.0, -2.0)), 2.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (0.0, 12.0)), 2.0));
+    });
+
+    it ('Segment and point distance 2', function () {
+        let segment = new OV.Segment2D (new OV.Coord2D (2.0, 2.0), new OV.Coord2D (4.0, 4.0));
+
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (2.0, 2.0)), 0.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (3.0, 3.0)), 0.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (4.0, 4.0)), 0.0));
+
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (4.0, 5.0)), 1.0));
+        assert.ok (OV.IsEqual (OV.SegmentPointDistance2D (segment, new OV.Coord2D (0.0, 2.0)), 2.0));
+    });
+});
+
 describe ('Quaternion', function () {
     it ('Create Quaternion', function () {
         let q1 = OV.QuaternionFromAxisAngle (new OV.Coord3D (1.0, 0.0, 0.0), Math.PI / 2.0);