/**
 * The lights of a set that take part in rendering, in the forms the renderer consumes. A layer
 * owns one for its lights and rebuilds it lazily when they change, and the lightmapper owns one
 * for the single light it bakes at a time.
 *
 * The central form is the light slots: the lights applied at runtime, in the order that gives each
 * its slot in a shader - `light<N>_` is the light at index N. The slot order is the same for every
 * mesh instance in a pass whatever its light mask selects, so a light's uniforms are dispatched
 * once per pass and each shader reads its own slots. The shader generator, the shader variant hash
 * and the light dispatch all read this one array, so they cannot disagree.
 *
 * @ignore
 */
export class LightList {
    /**
     * The lights applied at runtime, in slot order. Directional lights, then - when clustered
     * lighting is disabled - omni and spot lights, since clustered lighting supplies the local
     * lights another way. A light that only contributes to a lightmap reaches nothing at runtime
     * and takes no slot.
     *
     * @type {Light[]}
     */
    slots: Light[];
    /**
     * The enabled directional lights, in no particular order. Read by the shadow cull and the
     * gsplat shadow renderer, which look for the shadow casters among them.
     *
     * @type {Light[]}
     */
    directional: Light[];
    /**
     * The keys of the slot lights, joined in slot order. Identifies the layout of the lights, and
     * so the shader code and the uniform layout they generate.
     *
     * @type {string}
     */
    key: string;
    /**
     * A hash of {@link LightList#key}, for the shader variant hash.
     *
     * @type {number}
     */
    hash: number;
    /**
     * Whether the slots were built for clustered lighting.
     *
     * @type {boolean}
     */
    clustered: boolean;
    /**
     * Rebuilds every form from the given lights. The arrays are reused, so nothing is allocated
     * on a rebuild but the key.
     *
     * @param {Light[]} lights - The lights of the set, enabled or not.
     * @param {boolean} clustered - Whether clustered lighting is enabled, in which case the local
     * lights take no slot.
     */
    update(lights: Light[], clustered: boolean): void;
}
import type { Light } from '../light.js';