Extracting vertices from scenekit

Question

I\'m having a problem with understanding scenekit geometery.

I have the default cube from Blender, and I export as collada (DAE), and can bring it into scenekit....

Answer 1

The Swift 3 version:

    // `plane` is some kind of `SCNGeometry`

    let planeSources = plane.geometry.sources(for: SCNGeometrySource.Semantic.vertex)
    if let planeSource = planeSources.first {
        let stride = planeSource.dataStride
        let offset = planeSource.dataOffset
        let componentsPerVector = planeSource.componentsPerVector
        let bytesPerVector = componentsPerVector * planeSource.bytesPerComponent

        let vectors = [SCNVector3](repeating: SCNVector3Zero, count: planeSource.vectorCount)
        let vertices = vectors.enumerated().map({
            (index: Int, element: SCNVector3) -> SCNVector3 in

            let vectorData = UnsafeMutablePointer.allocate(capacity: componentsPerVector)
            let nsByteRange = NSMakeRange(index * stride + offset, bytesPerVector)
            let byteRange = Range(nsByteRange)

            let buffer = UnsafeMutableBufferPointer(start: vectorData, count: componentsPerVector)
                planeSource.data.copyBytes(to: buffer, from: byteRange)
            let vector = SCNVector3Make(buffer[0], buffer[1], buffer[2])
        })

        // Use `vertices` here: vertices[0].x, vertices[0].y, vertices[0].z
    }