backend/libs/three/geometries/ShapeGeometry.js

import { BufferGeometry } from '../core/BufferGeometry.js';
import { Float32BufferAttribute } from '../core/BufferAttribute.js';
import { Shape } from '../extras/core/Shape.js';
import { ShapeUtils } from '../extras/ShapeUtils.js';
import { Vector2 } from '../math/Vector2.js';

class ShapeGeometry extends BufferGeometry {
	constructor(shapes = new Shape([new Vector2(0, 0.5), new Vector2(-0.5, -0.5), new Vector2(0.5, -0.5)]), curveSegments = 12) {
		super();
		this.type = 'ShapeGeometry';

		this.parameters = {
			shapes: shapes,
			curveSegments: curveSegments,
		};

		// buffers

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

		// helper variables

		let groupStart = 0;
		let groupCount = 0;

		// allow single and array values for "shapes" parameter

		if (Array.isArray(shapes) === false) {
			addShape(shapes);
		} else {
			for (let i = 0; i < shapes.length; i++) {
				addShape(shapes[i]);

				this.addGroup(groupStart, groupCount, i); // enables MultiMaterial support

				groupStart += groupCount;
				groupCount = 0;
			}
		}

		// 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));

		// helper functions

		function addShape(shape) {
			const indexOffset = vertices.length / 3;
			const points = shape.extractPoints(curveSegments);

			let shapeVertices = points.shape;
			const shapeHoles = points.holes;

			// check direction of vertices

			if (ShapeUtils.isClockWise(shapeVertices) === false) {
				shapeVertices = shapeVertices.reverse();
			}

			for (let i = 0, l = shapeHoles.length; i < l; i++) {
				const shapeHole = shapeHoles[i];

				if (ShapeUtils.isClockWise(shapeHole) === true) {
					shapeHoles[i] = shapeHole.reverse();
				}
			}

			const faces = ShapeUtils.triangulateShape(shapeVertices, shapeHoles);

			// join vertices of inner and outer paths to a single array

			for (let i = 0, l = shapeHoles.length; i < l; i++) {
				const shapeHole = shapeHoles[i];
				shapeVertices = shapeVertices.concat(shapeHole);
			}

			// vertices, normals, uvs

			for (let i = 0, l = shapeVertices.length; i < l; i++) {
				const vertex = shapeVertices[i];

				vertices.push(vertex.x, vertex.y, 0);
				normals.push(0, 0, 1);
				uvs.push(vertex.x, vertex.y); // world uvs
			}

			// incides

			for (let i = 0, l = faces.length; i < l; i++) {
				const face = faces[i];

				const a = face[0] + indexOffset;
				const b = face[1] + indexOffset;
				const c = face[2] + indexOffset;

				indices.push(a, b, c);
				groupCount += 3;
			}
		}
	}

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

		const shapes = this.parameters.shapes;

		return toJSON(shapes, data);
	}

	static fromJSON(data, shapes) {
		const geometryShapes = [];

		for (let j = 0, jl = data.shapes.length; j < jl; j++) {
			const shape = shapes[data.shapes[j]];

			geometryShapes.push(shape);
		}

		return new ShapeGeometry(geometryShapes, data.curveSegments);
	}
}

function toJSON(shapes, data) {
	data.shapes = [];

	if (Array.isArray(shapes)) {
		for (let i = 0, l = shapes.length; i < l; i++) {
			const shape = shapes[i];

			data.shapes.push(shape.uuid);
		}
	} else {
		data.shapes.push(shapes.uuid);
	}

	return data;
}

export { ShapeGeometry, ShapeGeometry as ShapeBufferGeometry };