import { InjectionKey, Ref } from 'vue';
import { GameEngine, GameManager, GameSimulationView } from '@skewedaspect/sage';
/**
 * What sage-vue reads of a simulation: its two entity lookups. GameSimulation is invariant in its registry
 * type parameter, so naming only the members whose signature does not mention the registry is what lets a
 * simulation built from any registry satisfy this (design/ui.md#reaching-the-engine).
 */
export type ObservedSimulation = Pick<GameSimulationView, 'getEntity' | 'getEntitiesByTag'>;
/**
 * What sage-vue reads of an engine and nothing more: enough to hear the bus, run timers, look entities up, and
 * refresh views once a frame. Nothing in it needs Babylon, so a host with no render engine provides one; an engine
 * typed by any entity registry is one of these (design/ui.md#reaching-the-engine).
 */
export type ObservedEngine = Pick<GameEngine, 'bus' | 'timer'> & {
    readonly simulation: ObservedSimulation | null;
    readonly managers: {
        readonly gameManager: Pick<GameManager, 'registerFrameCallback'>;
    };
};
export declare const SAGE_ENGINE_KEY: InjectionKey<Readonly<Ref<ObservedEngine | null>>>;