import { FilamentInstance } from './FilamentInstance';
/**
 * Updates matrices according to glTF animation and skin definitions.
 *
 * Animator can be used for two things:
 * - Updating matrices in filament::TransformManager components according to glTF animation definitions.
 * - Updating bone matrices in filament::RenderableManager components according to glTF skin definitions.
 *
 * For a usage example, see the documentation for AssetLoader.
 */
export interface Animator {
    /**
     * Applies rotation, translation, and scale to entities that have been targeted by the given
     * animation definition. Uses filament::TransformManager.
     *
     * @param animationIndex Zero-based index for the animation of interest.
     * @param time Elapsed time of interest in seconds.
     */
    applyAnimation(animIndex: number, time: number): void;
    /**
     * Applies a blended transform to the union of nodes affected by two animations.
     * Used for cross-fading from a previous skinning-based animation or rigid body animation.
     *
     * First, this stashes the current transform hierarchy into a transient memory buffer.
     *
     * Next, this applies previousAnimIndex / previousAnimTime to the actual asset by internally
     * calling applyAnimation().
     *
     * Finally, the stashed local transforms are lerped (via the scale / translation / rotation
     * components) with their live counterparts, and the results are pushed to the asset.
     *
     * To achieve a cross fade effect with skinned models, clients will typically call animator
     * methods in this order: (1) applyAnimation (2) applyCrossFade (3) updateBoneMatrices. The
     * animation that clients pass to applyAnimation is the "current" animation corresponding to
     * alpha=1, while the "previous" animation passed to applyCrossFade corresponds to alpha=0.
     */
    applyCrossFade(previousAnimIndex: number, previousAnimTime: number, alpha: number): void;
    /**
     * Computes root-to-node transforms for all bone nodes, then passes
     * the results into filament::RenderableManager::setBones.
     * Uses filament::TransformManager and filament::RenderableManager.
     *
     * NOTE: this operation is independent of animation.
     */
    updateBoneMatrices(): void;
    /**
     * Will apply all transforms of the animation to the same entities/bones when calling {@linkcode updateBoneMatrices}.
     * This is useful if you have multiple assets sharing the same skeleton and you want to animate them in sync (e.g. clothing).
     * Internally calls {@linkcode applyAnimationToInstance}.
     *
     * @note Entities / bones are identified by name.
     *
     * @returns The id of the instance in the sync list.
     */
    addToSyncList(instance: FilamentInstance): number;
    /**
     * Will remove the instance from the sync list.
     */
    removeFromSyncList(instanceId: number): void;
    /**
     * Pass the identity matrix into all bone nodes, useful for returning to the T pose.
     *
     * NOTE: this operation is independent of animation.
     */
    resetBoneMatrices(): void;
    /** Returns the number of animation definitions in the glTF asset. */
    getAnimationCount(): number;
    /** Returns the number of animation definitions in the asset. */
    getAnimationDuration(animIndex: number): number;
    /**
     * Returns the name of the specified animation, or an
     * empty string if none was specified.
     */
    getAnimationName(animIndex: number): string;
}
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