backend/libs/three/geometries/TorusGeometry.js

import { BufferGeometry } from '../core/BufferGeometry.js';
import { Float32BufferAttribute } from '../core/BufferAttribute.js';
import { Vector3 } from '../math/Vector3.js';

class TorusGeometry extends BufferGeometry {
	constructor(radius = 1, tube = 0.4, radialSegments = 8, tubularSegments = 6, arc = Math.PI * 2) {
		super();
		this.type = 'TorusGeometry';

		this.parameters = {
			radius: radius,
			tube: tube,
			radialSegments: radialSegments,
			tubularSegments: tubularSegments,
			arc: arc,
		};

		radialSegments = Math.floor(radialSegments);
		tubularSegments = Math.floor(tubularSegments);

		// buffers

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

		// helper variables

		const center = new Vector3();
		const vertex = new Vector3();
		const normal = new Vector3();

		// generate vertices, normals and uvs

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

				// vertex

				vertex.x = (radius + tube * Math.cos(v)) * Math.cos(u);
				vertex.y = (radius + tube * Math.cos(v)) * Math.sin(u);
				vertex.z = tube * Math.sin(v);

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

				// normal

				center.x = radius * Math.cos(u);
				center.y = radius * Math.sin(u);
				normal.subVectors(vertex, center).normalize();

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

				// uv

				uvs.push(i / tubularSegments);
				uvs.push(j / radialSegments);
			}
		}

		// generate indices

		for (let j = 1; j <= radialSegments; j++) {
			for (let i = 1; i <= tubularSegments; i++) {
				// indices

				const a = (tubularSegments + 1) * j + i - 1;
				const b = (tubularSegments + 1) * (j - 1) + i - 1;
				const c = (tubularSegments + 1) * (j - 1) + i;
				const d = (tubularSegments + 1) * j + i;

				// faces

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

		// 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));
	}

	static fromJSON(data) {
		return new TorusGeometry(data.radius, data.tube, data.radialSegments, data.tubularSegments, data.arc);
	}
}

export { TorusGeometry, TorusGeometry as TorusBufferGeometry };