backend/libs/three/lights/SpotLight.js

import { Light } from './Light.js';
import { SpotLightShadow } from './SpotLightShadow.js';
import { Object3D } from '../core/Object3D.js';

class SpotLight extends Light {
	constructor(color, intensity, distance = 0, angle = Math.PI / 3, penumbra = 0, decay = 1) {
		super(color, intensity);

		this.type = 'SpotLight';

		this.position.copy(Object3D.DefaultUp);
		this.updateMatrix();

		this.target = new Object3D();

		this.distance = distance;
		this.angle = angle;
		this.penumbra = penumbra;
		this.decay = decay; // for physically correct lights, should be 2.

		this.shadow = new SpotLightShadow();
	}

	get power() {
		// compute the light's luminous power (in lumens) from its intensity (in candela)
		// by convention for a spotlight, luminous power (lm) = π * luminous intensity (cd)
		return this.intensity * Math.PI;
	}

	set power(power) {
		// set the light's intensity (in candela) from the desired luminous power (in lumens)
		this.intensity = power / Math.PI;
	}

	dispose() {
		this.shadow.dispose();
	}

	copy(source) {
		super.copy(source);

		this.distance = source.distance;
		this.angle = source.angle;
		this.penumbra = source.penumbra;
		this.decay = source.decay;

		this.target = source.target.clone();

		this.shadow = source.shadow.clone();

		return this;
	}
}

SpotLight.prototype.isSpotLight = true;

export { SpotLight };