rabbit-ear/module/graph/planarize/intersectAllEdges.js

origami design library

/* Rabbit Ear 0.9.4 alpha 2024-04-20 (c) Kraft, GNU GPLv3 License */

import { EPSILON } from '../../math/constant.js';
import { includeS, epsilonEqual } from '../../math/compare.js';
import { intersectLineLine } from '../../math/intersect.js';
import { edgesToLines2 } from '../edges/lines.js';
import { makeVerticesEdgesUnsorted } from '../make/verticesEdges.js';

const intersectAllEdges = ({
	vertices_coords,
	vertices_edges,
	edges_vertices,
}, epsilon = EPSILON) => {
	if (!vertices_edges) {
		vertices_edges = makeVerticesEdgesUnsorted({ edges_vertices });
	}
	const edgesEdgesLookup = edges_vertices.map(() => ({}));
	edges_vertices.forEach((vertices, e) => vertices
		.flatMap(v => vertices_edges[v])
		.forEach(edge => {
			edgesEdgesLookup[e][edge] = true;
			edgesEdgesLookup[edge][e] = true;
		}));
	const lines = edgesToLines2({ vertices_coords, edges_vertices });
	const results = [];
	for (let i = 0; i < edges_vertices.length - 1; i += 1) {
		for (let j = i + 1; j < edges_vertices.length; j += 1) {
			if (edgesEdgesLookup[i][j]) { continue; }
			const { a, b, point } = intersectLineLine(
				lines[i],
				lines[j],
				includeS,
				includeS,
				epsilon,
			);
			if (point) {
				if ((epsilonEqual(a, 0) || epsilonEqual(a, 1))
					&& (epsilonEqual(b, 0) || epsilonEqual(b, 1))) {
					continue;
				}
				results.push({ i, j, a, b, point });
			}
		}
	}
	return results;
};

export { intersectAllEdges };