/// <reference types="webxr" />
import type { NgtState } from '../types';
declare type GlobalRenderCallback = (timeStamp: number) => void;
/**
 * Adds a global render callback which is called each frame.
 */
export declare function addCallback(callback: GlobalRenderCallback): () => void;
/**
 * Adds a global after-render callback which is called each frame.
 */
export declare function addAfterCallback(callback: GlobalRenderCallback): () => void;
/**
 * Adds a global callback which is called when rendering stops.
 */
export declare function addTail(callback: GlobalRenderCallback): () => void;
export declare function render(timestamp: number, state: () => NgtState, frame?: XRFrame): number;
export declare function createLoop(rootStateMap: Map<Element, () => NgtState>): {
    loop: (timestamp: number) => void;
    /**
     * Invalidates the view, requesting a frame to be rendered. Will globally invalidate unless passed a root's state.
     */
    invalidate: (state?: () => NgtState, frames?: number) => void;
    /**
     * Advances the frameloop and runs render effects, useful for when manually rendering via `frameloop="never"`.
     */
    advance: (timestamp: number, runGlobalEffects?: boolean, state?: () => NgtState, frame?: XRFrame) => void;
};
export {};