backend/libs/three/helpers/SpotLightHelper.js

import { Vector3 } from '../math/Vector3.js';
import { Object3D } from '../core/Object3D.js';
import { LineSegments } from '../objects/LineSegments.js';
import { LineBasicMaterial } from '../materials/LineBasicMaterial.js';
import { Float32BufferAttribute } from '../core/BufferAttribute.js';
import { BufferGeometry } from '../core/BufferGeometry.js';

const _vector = /*@__PURE__*/ new Vector3();

class SpotLightHelper extends Object3D {
	constructor(light, color) {
		super();
		this.light = light;
		this.light.updateMatrixWorld();

		this.matrix = light.matrixWorld;
		this.matrixAutoUpdate = false;

		this.color = color;

		const geometry = new BufferGeometry();

		const positions = [0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, -1, 1];

		for (let i = 0, j = 1, l = 32; i < l; i++, j++) {
			const p1 = (i / l) * Math.PI * 2;
			const p2 = (j / l) * Math.PI * 2;

			positions.push(Math.cos(p1), Math.sin(p1), 1, Math.cos(p2), Math.sin(p2), 1);
		}

		geometry.setAttribute('position', new Float32BufferAttribute(positions, 3));

		const material = new LineBasicMaterial({ fog: false, toneMapped: false });

		this.cone = new LineSegments(geometry, material);
		this.add(this.cone);

		this.update();
	}

	dispose() {
		this.cone.geometry.dispose();
		this.cone.material.dispose();
	}

	update() {
		this.light.updateMatrixWorld();

		const coneLength = this.light.distance ? this.light.distance : 1000;
		const coneWidth = coneLength * Math.tan(this.light.angle);

		this.cone.scale.set(coneWidth, coneWidth, coneLength);

		_vector.setFromMatrixPosition(this.light.target.matrixWorld);

		this.cone.lookAt(_vector);

		if (this.color !== undefined) {
			this.cone.material.color.set(this.color);
		} else {
			this.cone.material.color.copy(this.light.color);
		}
	}
}

export { SpotLightHelper };