import type { GLTF } from 'three/examples/jsm/loaders/GLTFLoader' ; import type { GLTFPrimitive , GLTFSchema } from '../types' ; function extractPrimitivesInternal ( gltf , nodeIndex , node ) { /**
     * Let's list up every possible patterns that parsed gltf nodes with a mesh can have,,,
     *
     * "*" indicates that those meshes should be listed up using this function
     *
     * ### A node with a (mesh, a signle primitive)
     *
     * - `THREE.Mesh`: The only primitive of the mesh *
     *
     * ### A node with a (mesh, multiple primitives)
     *
     * - `THREE.Group`: The root of the mesh
     *   - `THREE.Mesh`: A primitive of the mesh *
     *   - `THREE.Mesh`: A primitive of the mesh (2) *
     *
     * ### A node with a (mesh, multiple primitives) AND (a child with a mesh, a single primitive)
     *
     * - `THREE.Group`: The root of the mesh
     *   - `THREE.Mesh`: A primitive of the mesh *
     *   - `THREE.Mesh`: A primitive of the mesh (2) *
     *   - `THREE.Mesh`: A primitive of a MESH OF THE CHILD
     *
     * ### A node with a (mesh, multiple primitives) AND (a child with a mesh, multiple primitives)
     *
     * - `THREE.Group`: The root of the mesh
     *   - `THREE.Mesh`: A primitive of the mesh *
     *   - `THREE.Mesh`: A primitive of the mesh (2) *
     *   - `THREE.Group`: The root of a MESH OF THE CHILD
     *     - `THREE.Mesh`: A primitive of the mesh of the child
     *     - `THREE.Mesh`: A primitive of the mesh of the child (2)
     *
     * ### A node with a (mesh, multiple primitives) BUT the node is a bone
     *
     * - `THREE.Bone`: The root of the node, as a bone
     *   - `THREE.Group`: The root of the mesh
     *     - `THREE.Mesh`: A primitive of the mesh *
     *     - `THREE.Mesh`: A primitive of the mesh (2) *
     *
     * ### A node with a (mesh, multiple primitives) AND (a child with a mesh, multiple primitives) BUT the node is a bone
     *
     * - `THREE.Bone`: The root of the node, as a bone
     *   - `THREE.Group`: The root of the mesh
     *     - `THREE.Mesh`: A primitive of the mesh *
     *     - `THREE.Mesh`: A primitive of the mesh (2) *
     *   - `THREE.Group`: The root of a MESH OF THE CHILD
     *     - `THREE.Mesh`: A primitive of the mesh of the child
     *     - `THREE.Mesh`: A primitive of the mesh of the child (2)
     *
     * ...I will take a strategy that traverses the root of the node and take first (primitiveCount) meshes.
     */ const schemaNode = gltf . parser . json . nodes [ nodeIndex ] ; const meshIndex = schemaNode . mesh ; if ( meshIndex == null ) { return null ; } const schemaMesh = gltf . parser . json . meshes [ meshIndex ] ; const primitiveCount = schemaMesh . primitives . length ; const primitives = [ ] ; node . traverse ( ( object ) => { if ( primitives . length < primitiveCount ) { if ( ( object as any ) . isMesh ) { primitives . push ( object as GLTFPrimitive ) ; } } } ) ; return primitives ; } param gltf param nodeIndex export async function gltfExtractPrimitivesFromNode ( gltf , nodeIndex ) { const node = await gltf . parser . getDependency ( 'node' , nodeIndex ) ; return extractPrimitivesInternal ( gltf , nodeIndex , node ) ; } /**
 * Extract primitives ( `THREE.Mesh[]` ) of nodes from a loaded GLTF.
 * See  gltfExtractPrimitivesFromNode for more details.
 *
 * It returns a map from node index to extraction result.
 * If a node does not have a mesh, the entry for the node will not be put in the returning map.
 *
 *  param gltf export async function gltfExtractPrimitivesFromNodes ( gltf ) { const nodes = await gltf . parser . getDependencies ( 'node' ) ; const map = new Map < number , GLTFPrimitive [ ] > ( ) ; nodes . forEach ( ( node , index ) => { const result = extractPrimitivesInternal ( gltf , index , node ) ; if ( result != null ) { map . set ( index , result ) ; } } ) ; return map ; }