import { VecN } from '@holotope/core';
import { RigidBody4 } from './rigid-body4.js';
export interface PhysicsWorld4Options {
    /** Default is y-down: [0, -9.81, 0, 0]. */
    gravity?: VecN | ArrayLike<number>;
}
/** Called after force integration and before pose integration in each substep. */
export type PhysicsWorld4VelocityConstraintCallback = (substepDt: number, substepIndex: number) => void;
/** Fixed-step world with an explicit velocity-constraint callback seam. */
export declare class PhysicsWorld4 {
    readonly gravity: VecN;
    readonly bodies: RigidBody4[];
    constructor(options?: PhysicsWorld4Options);
    addBody(body: RigidBody4): this;
    removeBody(body: RigidBody4): this;
    /**
     * Integrates force/torque into velocities without moving any pose.
     *
     * This low-level stage exists so event-driven contact can split pose
     * integration at a time of impact. Accumulators remain live until
     * `clearAccumulators()`; ordinary callers should continue to use `step()`.
     */
    integrateVelocities(dt: number): this;
    /** Advances every body pose using its current post-constraint velocity. */
    integratePoses(dt: number): this;
    /** Clears forces and torques after a complete manually staged step. */
    clearAccumulators(): this;
    /**
     * Advances force, momentum, velocity, position, and Spin(4) orientation.
     * Forces and torques are held constant across substeps, then cleared. A
     * finite `dt` of zero is a complete no-op, including accumulator retention;
     * this makes the first zero delta from a renderer clock safe to forward.
     */
    step(dt: number, substeps?: number, solveVelocityConstraints?: PhysicsWorld4VelocityConstraintCallback): void;
}
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