backend/libs/three/geometries/TubeGeometry.js

import { BufferGeometry } from '../core/BufferGeometry.js';
import { Float32BufferAttribute } from '../core/BufferAttribute.js';
import * as Curves from '../extras/curves/Curves.js';
import { Vector2 } from '../math/Vector2.js';
import { Vector3 } from '../math/Vector3.js';

class TubeGeometry extends BufferGeometry {
	constructor(
		path = new Curves['QuadraticBezierCurve3'](new Vector3(-1, -1, 0), new Vector3(-1, 1, 0), new Vector3(1, 1, 0)),
		tubularSegments = 64,
		radius = 1,
		radialSegments = 8,
		closed = false
	) {
		super();
		this.type = 'TubeGeometry';

		this.parameters = {
			path: path,
			tubularSegments: tubularSegments,
			radius: radius,
			radialSegments: radialSegments,
			closed: closed,
		};

		const frames = path.computeFrenetFrames(tubularSegments, closed);

		// expose internals

		this.tangents = frames.tangents;
		this.normals = frames.normals;
		this.binormals = frames.binormals;

		// helper variables

		const vertex = new Vector3();
		const normal = new Vector3();
		const uv = new Vector2();
		let P = new Vector3();

		// buffer

		const vertices = [];
		const normals = [];
		const uvs = [];
		const indices = [];

		// create buffer data

		generateBufferData();

		// build geometry

		this.setIndex(indices);
		this.setAttribute('position', new Float32BufferAttribute(vertices, 3));
		this.setAttribute('normal', new Float32BufferAttribute(normals, 3));
		this.setAttribute('uv', new Float32BufferAttribute(uvs, 2));

		// functions

		function generateBufferData() {
			for (let i = 0; i < tubularSegments; i++) {
				generateSegment(i);
			}

			// if the geometry is not closed, generate the last row of vertices and normals
			// at the regular position on the given path
			//
			// if the geometry is closed, duplicate the first row of vertices and normals (uvs will differ)

			generateSegment(closed === false ? tubularSegments : 0);

			// uvs are generated in a separate function.
			// this makes it easy compute correct values for closed geometries

			generateUVs();

			// finally create faces

			generateIndices();
		}

		function generateSegment(i) {
			// we use getPointAt to sample evenly distributed points from the given path

			P = path.getPointAt(i / tubularSegments, P);

			// retrieve corresponding normal and binormal

			const N = frames.normals[i];
			const B = frames.binormals[i];

			// generate normals and vertices for the current segment

			for (let j = 0; j <= radialSegments; j++) {
				const v = (j / radialSegments) * Math.PI * 2;

				const sin = Math.sin(v);
				const cos = -Math.cos(v);

				// normal

				normal.x = cos * N.x + sin * B.x;
				normal.y = cos * N.y + sin * B.y;
				normal.z = cos * N.z + sin * B.z;
				normal.normalize();

				normals.push(normal.x, normal.y, normal.z);

				// vertex

				vertex.x = P.x + radius * normal.x;
				vertex.y = P.y + radius * normal.y;
				vertex.z = P.z + radius * normal.z;

				vertices.push(vertex.x, vertex.y, vertex.z);
			}
		}

		function generateIndices() {
			for (let j = 1; j <= tubularSegments; j++) {
				for (let i = 1; i <= radialSegments; i++) {
					const a = (radialSegments + 1) * (j - 1) + (i - 1);
					const b = (radialSegments + 1) * j + (i - 1);
					const c = (radialSegments + 1) * j + i;
					const d = (radialSegments + 1) * (j - 1) + i;

					// faces

					indices.push(a, b, d);
					indices.push(b, c, d);
				}
			}
		}

		function generateUVs() {
			for (let i = 0; i <= tubularSegments; i++) {
				for (let j = 0; j <= radialSegments; j++) {
					uv.x = i / tubularSegments;
					uv.y = j / radialSegments;

					uvs.push(uv.x, uv.y);
				}
			}
		}
	}

	toJSON() {
		const data = super.toJSON();

		data.path = this.parameters.path.toJSON();

		return data;
	}

	static fromJSON(data) {
		// This only works for built-in curves (e.g. CatmullRomCurve3).
		// User defined curves or instances of CurvePath will not be deserialized.
		return new TubeGeometry(new Curves[data.path.type]().fromJSON(data.path), data.tubularSegments, data.radius, data.radialSegments, data.closed);
	}
}

export { TubeGeometry, TubeGeometry as TubeBufferGeometry };