plotboilerplate
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A simple javascript plotting boilerplate for 2d stuff.
51 lines • 2.11 kB
JavaScript
;
/**
* @requires Line
* @requires Vertex
*
* @author Ikaros Kappler
* @date 2020-12-04
* @modified 2020-12-09 Ported from vanilla JS to Typescript.
* @modified 2024-11-22 Fixed a type error in line 41.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.findPolygonSelfIntersections = void 0;
var Line_1 = require("../../Line");
var Vertex_1 = require("../../Vertex");
/**
* Collect all self-intersection points of the given polygon.
*
* If the given polygon (vertices) is not self intersecting then the returned array is empty.
*
* @name findPolygonSelfIntersections
* @param {Array<Vertex>} vertices - The vertices that form the polygon.
* @return {Array<Vertex>}
*/
var findPolygonSelfIntersections = function (vertices) {
var pointList = [];
var lineA = new Line_1.Line(new Vertex_1.Vertex(), new Vertex_1.Vertex());
var lineB = new Line_1.Line(new Vertex_1.Vertex(), new Vertex_1.Vertex());
var n = vertices.length;
for (var a = 0; a < n; a++) {
lineA.a.set(vertices[a]);
lineA.b.set(vertices[(a + 1) % n]);
for (var b = 0; b < n; b++) {
// Same edge or neighbour edges intersect by definition.
// Skip them.
if (a == b || a + 1 == b || a == b + 1 || (a == 0 && b + 1 == n) || (b == 0 && a + 1 == n))
continue;
lineB.a.set(vertices[b]);
lineB.b.set(vertices[(b + 1) % n]);
// Commpute the intersection point of the (infinite) lines.
// The point is undefined if and only if both line are parallel (co-linear).
var intersectionPoint = lineA.intersection(lineB);
// Check if the intersection point is on both (finite) edges of the polygon.
if (intersectionPoint && lineA.hasPoint(intersectionPoint) && lineB.hasPoint(intersectionPoint)) {
pointList.push(intersectionPoint);
}
}
}
return pointList;
};
exports.findPolygonSelfIntersections = findPolygonSelfIntersections;
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