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 Version

The Objective-C version and this are essentially identical.

let planeSources = _planeNode?.geometry?.geometrySourcesForSemantic(SCNGeometrySourceSemanticVertex)
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](count: planeSource.vectorCount, repeatedValue: SCNVector3Zero)
    let vertices = vectors.enumerate().map({
        (index: Int, element: SCNVector3) -> SCNVector3 in
        var vectorData = [Float](count: componentsPerVector, repeatedValue: 0)
        let byteRange = NSMakeRange(index * stride + offset, bytesPerVector)
        planeSource.data.getBytes(&vectorData, range: byteRange)
        return SCNVector3Make(vectorData[0], vectorData[1], vectorData[2])
    })

    // You have your vertices, now what?
}