Infinite Loop when calling unify for multipolygon with touching faces

[axtavt]

Attempt to unify polygons when one of them is a particular multipolygon with touching faces (valid) causes Error: Cannot complete boolean operation:

const a = new Flatten.Polygon([
    [
        point(70, 10),
        point(80, 10),
        point(80, 50),
        point(70, 50),
    ],
    [
        point(90, 10),
        point(100, 10),
        point(100, 50),
        point(90, 50),
    ],
    [
        point(100, 0),
        point(120, 0),
        point(120, 10),
        point(100, 10),
    ],
]);
const b = new Flatten.Polygon([ point(0, 0), point(100, 0), point(100, 10), point(0, 10) ]);

const c = Flatten.BooleanOperations.unify(a, b); // Error: Cannot complete boolean operation

It's caused by incorrect heaviour of ray_shoot() for such a mutlipolygon:

const polygon = new Flatten.Polygon();
polygon.addFace([ point(90, 10), point(100, 10), point(100, 50), point(90, 50) ]);
polygon.addFace([ point(100, 0), point(120, 0), point(120, 10), point(100, 10) ]);

let contains = ray_shoot(polygon, point(85, 10)); // should be OUTSIDE, returns INSIDE instead

[axtavt]

Created PR #172

[axtavt]

Case 2 - incorrect result of ray_shoot() for polygon with self-touching face:

const polygon = new Flatten.Polygon();
polygon.addFace([
    point(90, 10), point(100, 10), point(100, 50), point(110, 50), point(110, 10), point(100, 10), point(100, 0),
    point(120, 0), point(120, 60), point(90, 60)
]);

let contains = ray_shoot(polygon, point(85, 10)); // should be OUTSIDE, returns INSIDE instead

[axtavt]

Created PR #173

[alexbol99]

Hi @axtavt , Thank you so much for your contribution I will check your PR's

[alexbol99]

Hello @axtavt , You PR is great but I made a small change: when sorting intersection points, I added sorting by face_index and then by edge arc_length, that ensure that two points originated from same edges, will be neighbors in sorted array. Then if the first point is counted, second one is ignored. Thank you for noticing and fixing this problem.

[alexbol99]

Fixed release in v1.5.2