如何在Swift中为SCNGeometrySource构建数据

struct Vertex {
    var position: vector_float3
    var texCoord: vector_float2
}

let vertices: [Vertex] = [
    Vertex(position: vector_float3(-0.5, -0.5, 0), texCoord: vector_float2(0, 0)),
    Vertex(position: vector_float3(0.5, -0.5, 0), texCoord: vector_float2(1, 0)),
    Vertex(position: vector_float3(-0.5, 0.5, 0), texCoord: vector_float2(0, 1)),
    Vertex(position: vector_float3(0.5, 0.5, 0), texCoord: vector_float2(1, 1))
]

let vertexData = NSData(bytes: vertices, length: MemoryLayout<Vertex>.stride * vertices.count)
let vertexSource = SCNGeometrySource(data: vertexData as Data, semantic: .vertex, vectorCount: vertices.count, usesFloatComponents: true, componentsPerVector: 3, bytesPerComponent: MemoryLayout<Float>.stride, dataOffset: 0, dataStride: MemoryLayout<Vertex>.stride)
let texCoordData = NSData(bytes: vertices, length: MemoryLayout<Vertex>.stride * vertices.count)
let texCoordSource = SCNGeometrySource(data: texCoordData as Data, semantic: .texcoord, vectorCount: vertices.count, usesFloatComponents: true, componentsPerVector: 2, bytesPerComponent: MemoryLayout<Float>.stride, dataOffset: MemoryLayout<vector_float3>.stride, dataStride: MemoryLayout<Vertex>.stride)

let geometry = SCNGeometry(sources: [vertexSource, texCoordSource], elements: [])