/**
 * @holoscript/core LOD Types
 *
 * Comprehensive Level of Detail (LOD) type system for HoloScript.
 * Provides types, helpers, and configuration for LOD management.
 */
/** LOD selection strategy */
export type LODStrategy = 'distance' | 'screenSize' | 'performance' | 'manual' | 'hybrid';
/** LOD transition mode */
export type LODTransition = 'instant' | 'crossfade' | 'dither' | 'morph';
/** Mesh simplification algorithm */
export type SimplificationAlgorithm = 'quadricError' | 'edgeCollapse' | 'vertexClustering' | 'voxel';
/** Features that can be disabled at lower LODs */
export type LODFeature = 'shadows' | 'normals' | 'specular' | 'animation' | 'reflections' | 'particles' | 'physics' | 'skinning';
/**
 * Single LOD level configuration
 */
export interface LODLevel {
    /** LOD level (0 = highest detail) */
    level: number;
    /** Distance threshold for this LOD (world units) */
    distance: number;
    /** Screen coverage threshold (0-1, where 1 = full screen) */
    screenCoverage?: number;
    /** Polygon reduction ratio (0-1, where 1 = full detail) */
    polygonRatio: number;
    /** Texture resolution multiplier (0-1) */
    textureScale: number;
    /** Asset path for pre-generated LOD mesh */
    assetPath?: string;
    /** Features disabled at this LOD */
    disabledFeatures: LODFeature[];
    /** Custom priority for this level */
    priority?: number;
    /** Triangle count at this LOD */
    triangleCount?: number;
    /** Memory footprint in bytes */
    memoryFootprint?: number;
}
/**
 * LOD group configuration for an object
 */
export interface LODConfig {
    /** Unique identifier */
    id: string;
    /** Selection strategy */
    strategy: LODStrategy;
    /** Transition mode between levels */
    transition: LODTransition;
    /** Transition duration in seconds */
    transitionDuration: number;
    /** LOD levels (sorted by detail: 0 = highest) */
    levels: LODLevel[];
    /** Hysteresis factor to prevent LOD flickering */
    hysteresis: number;
    /** Bias to prefer higher/lower LODs (-1 to 1) */
    bias: number;
    /** Enable LOD fading */
    fadeEnabled: boolean;
    /** Maximum LOD level to use (limit for performance) */
    maxLevel?: number;
    /** Force specific LOD level (for debugging) */
    forcedLevel?: number;
    /** Whether this LOD config is enabled */
    enabled: boolean;
}
/**
 * LOD group containing multiple objects with shared LOD
 */
export interface LODGroup {
    /** Group identifier */
    id: string;
    /** Group name */
    name: string;
    /** Object IDs in this group */
    objectIds: string[];
    /** Shared LOD configuration */
    config: LODConfig;
    /** Bounding sphere center for distance calculation */
    boundingCenter: [number, number, number];
    /** Bounding sphere radius */
    boundingRadius: number;
    /** Current active LOD level */
    currentLevel: number;
    /** Is group visible */
    visible: boolean;
}
/**
 * LOD hierarchy for hierarchical LOD (HLOD)
 */
export interface LODHierarchy {
    /** Root node ID */
    rootId: string;
    /** Child hierarchies */
    children: LODHierarchy[];
    /** Combined mesh for this hierarchy level */
    combinedMeshPath?: string;
    /** Distance threshold for using combined mesh */
    combineDistance: number;
    /** Whether to use impostor (billboard) at far distances */
    useImpostor: boolean;
    /** Impostor texture path */
    impostorPath?: string;
}
/**
 * State of LOD selection for an object
 */
export interface LODState {
    /** Object ID */
    objectId: string;
    /** Current LOD level */
    currentLevel: number;
    /** Previous LOD level */
    previousLevel: number;
    /** Transition progress (0-1) */
    transitionProgress: number;
    /** Is transitioning between levels */
    isTransitioning: boolean;
    /** Distance to camera */
    cameraDistance: number;
    /** Screen coverage (0-1) */
    screenCoverage: number;
    /** Last update timestamp */
    lastUpdate: number;
    /** Frame time for last selection */
    selectionTime: number;
}
/**
 * LOD metrics for performance monitoring
 */
export interface LODMetrics {
    /** Total objects with LOD */
    totalObjects: number;
    /** Objects per LOD level */
    objectsPerLevel: Map<number, number>;
    /** Total triangles rendered */
    trianglesRendered: number;
    /** Triangles saved by LOD */
    trianglesSaved: number;
    /** Memory saved by LOD (bytes) */
    memorySaved: number;
    /** Average LOD level */
    averageLODLevel: number;
    /** LOD transitions this frame */
    transitionsThisFrame: number;
    /** Selection time (ms) */
    selectionTimeMs: number;
}
/**
 * Options for automatic LOD generation
 */
export interface LODGenerationOptions {
    /** Number of LOD levels to generate */
    levelCount: number;
    /** Target reduction per level (e.g., 0.5 = halve triangles each level) */
    reductionPerLevel: number;
    /** Simplification algorithm */
    algorithm: SimplificationAlgorithm;
    /** Preserve UV seams */
    preserveUVSeams: boolean;
    /** Preserve hard edges */
    preserveHardEdges: boolean;
    /** Preserve material boundaries */
    preserveMaterialBoundaries: boolean;
    /** Maximum error tolerance */
    maxError: number;
    /** Lock border vertices */
    lockBorders: boolean;
    /** Generate texture atlases for lower LODs */
    generateAtlases: boolean;
    /** Distance ratios for each level */
    distanceRatios?: number[];
}
/**
 * Result of LOD generation
 */
export interface LODGenerationResult {
    /** Success status */
    success: boolean;
    /** Generated levels */
    levels: GeneratedLODLevel[];
    /** Total time to generate (ms) */
    generationTimeMs: number;
    /** Warnings during generation */
    warnings: string[];
    /** Errors if failed */
    errors: string[];
}
/**
 * Single generated LOD level
 */
export interface GeneratedLODLevel {
    /** LOD level */
    level: number;
    /** Triangle count */
    triangleCount: number;
    /** Vertex count */
    vertexCount: number;
    /** Reduction ratio from original */
    reductionRatio: number;
    /** Visual error metric */
    errorMetric: number;
    /** Generated mesh data (positions) */
    positions: Float32Array;
    /** Generated mesh data (normals) */
    normals?: Float32Array;
    /** Generated mesh data (UVs) */
    uvs?: Float32Array;
    /** Generated mesh data (indices) */
    indices: Uint32Array;
}
/** Default LOD level configuration */
export declare const DEFAULT_LOD_LEVEL: LODLevel;
/** Default LOD configuration */
export declare const DEFAULT_LOD_CONFIG: LODConfig;
/** Default LOD generation options */
export declare const DEFAULT_GENERATION_OPTIONS: LODGenerationOptions;
/** Standard distance thresholds for 3 LOD levels */
export declare const STANDARD_DISTANCES: number[];
/** Standard polygon ratios for 3 LOD levels */
export declare const STANDARD_RATIOS: number[];
/**
 * Create a LOD level with defaults
 */
export declare function createLODLevel(level: number, distance: number, polygonRatio: number, options?: Partial<LODLevel>): LODLevel;
/**
 * Create a standard LOD configuration with N levels
 */
export declare function createStandardLODConfig(id: string, levelCount?: number, baseDistance?: number, options?: Partial<LODConfig>): LODConfig;
/**
 * Create LOD group from multiple objects
 */
export declare function createLODGroup(id: string, name: string, objectIds: string[], config: LODConfig, boundingCenter?: [number, number, number], boundingRadius?: number): LODGroup;
/**
 * Create initial LOD state for an object
 */
export declare function createLODState(objectId: string): LODState;
/**
 * Create empty LOD metrics
 */
export declare function createLODMetrics(): LODMetrics;
/**
 * Calculate LOD level from distance using config
 */
export declare function selectLODLevelByDistance(distance: number, levels: LODLevel[], hysteresis?: number, currentLevel?: number): number;
/**
 * Calculate LOD level from screen coverage
 */
export declare function selectLODLevelByScreenCoverage(screenCoverage: number, levels: LODLevel[]): number;
/**
 * Calculate screen coverage from distance and object size
 */
export declare function calculateScreenCoverage(distance: number, objectRadius: number, fov?: number, _screenHeight?: number): number;
/**
 * Get triangle count saved by current LOD level
 */
export declare function getTrianglesSaved(levels: LODLevel[], currentLevel: number, originalTriangles: number): number;
/**
 * Validate LOD configuration
 */
export declare function validateLODConfig(config: LODConfig): {
    valid: boolean;
    errors: string[];
};
/**
 * Merge two LOD configurations
 */
export declare function mergeLODConfigs(base: LODConfig, override: Partial<LODConfig>): LODConfig;
/**
 * Get recommended LOD count based on object size and complexity
 */
export declare function getRecommendedLODCount(triangleCount: number, _boundingRadius: number): number;
/**
 * Calculate optimal distance thresholds for LOD levels
 */
export declare function calculateOptimalDistances(boundingRadius: number, levelCount: number, maxViewDistance?: number): number[];
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