/**
 * PhysicsStep.ts
 *
 * Fixed-timestep physics wrapper that integrates with the SpatialEngine.
 * Implements the EngineSystem interface, running PhysicsWorld at a
 * deterministic tick rate and syncing body transforms back to SceneNodes.
 *
 * @module engine
 */
import type { EngineSystem } from './SpatialEngine';
export interface Vec3 {
    x: number;
    y: number;
    z: number;
    [index: number]: number;
}
export interface PhysicsBodyState {
    id: string;
    position: Vec3;
    rotation: Vec3;
    velocity: Vec3;
    angularVelocity: Vec3;
    mass: number;
    isStatic: boolean;
    restitution: number;
    friction: number;
}
export interface CollisionEvent {
    bodyA: string;
    bodyB: string;
    contactPoint: Vec3;
    normal: Vec3;
    impulse: number;
}
export type CollisionCallback = (event: CollisionEvent) => void;
export declare class PhysicsStep implements EngineSystem {
    readonly name = "PhysicsStep";
    readonly priority = 100;
    private bodies;
    private gravity;
    private collisionCallbacks;
    private broadphaseGrid;
    private cellSize;
    setGravity(x: number, y: number, z: number): void;
    setCellSize(size: number): void;
    onCollision(callback: CollisionCallback): void;
    addBody(body: PhysicsBodyState): void;
    removeBody(id: string): boolean;
    getBody(id: string): PhysicsBodyState | undefined;
    getAllBodies(): PhysicsBodyState[];
    fixedUpdate(dt: number): void;
    private resolveCollision;
    private hashPosition;
    /** Raycast against all bodies, returns first hit. */
    raycast(origin: Vec3, direction: Vec3, maxDist: number): {
        bodyId: string;
        distance: number;
        point: Vec3;
    } | null;
    /** Get count of active (non-static) bodies. */
    getActiveBodyCount(): number;
    destroy(): void;
}
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