/**
 * Per-triangle BVH for closest-point queries (BIM ↔ scan deviation).
 *
 * Distinct from `bvh.ts` which is a per-mesh BVH used for raycasting:
 * for closest-point we want fine-grained pruning, so each leaf holds
 * a contiguous range of triangles. The build also flattens the tree
 * to a `Float32Array` ready for direct GPU upload — no second pass.
 *
 * Node layout (32 bytes = 8 floats per node, packed Float32 + bitcast u32):
 *   [0..2] aabbMin       (vec3<f32>)
 *   [3]    childA / triStart      (u32 bitcast: leaf flag = high bit)
 *   [4..6] aabbMax       (vec3<f32>)
 *   [7]    childB / triCount      (u32 bitcast)
 *
 * Triangle layout (48 bytes = 12 floats per triangle):
 *   [0..2]   v0 (vec3)
 *   [3..5]   v1 (vec3)
 *   [6..8]   v2 (vec3)
 *   [9..11]  normalised face normal (vec3) — sign convention: outward
 *            from mesh interior assuming CCW winding (right-hand rule)
 *
 * Maximum supported triangles: ~2³¹ (one bit reserved for the leaf
 * flag). Real BIMs top out around 10⁷ triangles before other bottle-
 * necks kick in.
 */
import type { MeshData } from '@ifc-lite/geometry';
export interface TriangleBVHResult {
    /** Flat node buffer (Float32Array). Each node is 8 floats. */
    nodes: Float32Array;
    /** Flat triangle buffer (Float32Array). Each triangle is 12 floats. */
    triangles: Float32Array;
    /** Total number of triangles. */
    triangleCount: number;
    /** Total number of nodes (root at index 0). */
    nodeCount: number;
    /** Number of source meshes folded into this BVH. */
    meshCount: number;
    /** Aggregate bounds of all triangles. */
    bounds: {
        min: [number, number, number];
        max: [number, number, number];
    };
}
/**
 * Build the per-triangle BVH.
 *
 * Splits leaves until each holds at most `maxTrisPerLeaf` triangles
 * (default 16, balancing tree depth vs. per-leaf work). Median split
 * along the longest AABB axis — fast O(n log n) build, no SAH for v1.
 *
 * For typical BIMs (1M triangles) the build runs in ~1–3 seconds on
 * the main thread. Acceptable since it only re-runs when the mesh
 * set changes (load / federation update).
 */
export declare function buildTriangleBVH(meshes: ReadonlyArray<MeshData>, options?: {
    maxTrisPerLeaf?: number;
}): TriangleBVHResult;
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