Drawing a line between two points using SceneKit

Question

I have two points (let\'s call them pointA and pointB) of type SCNVector3. I want to draw a line between them. Seems like it should be easy, but can\'t find a way to do it.<

Answer 1

Here's one solution

class func lineBetweenNodeA(nodeA: SCNNode, nodeB: SCNNode) -> SCNNode {
    let positions: [Float32] = [nodeA.position.x, nodeA.position.y, nodeA.position.z, nodeB.position.x, nodeB.position.y, nodeB.position.z]
    let positionData = NSData(bytes: positions, length: MemoryLayout.size*positions.count)
    let indices: [Int32] = [0, 1]
    let indexData = NSData(bytes: indices, length: MemoryLayout.size * indices.count)

    let source = SCNGeometrySource(data: positionData as Data, semantic: SCNGeometrySource.Semantic.vertex, vectorCount: indices.count, usesFloatComponents: true, componentsPerVector: 3, bytesPerComponent: MemoryLayout.size, dataOffset: 0, dataStride: MemoryLayout.size * 3)
    let element = SCNGeometryElement(data: indexData as Data, primitiveType: SCNGeometryPrimitiveType.line, primitiveCount: indices.count, bytesPerIndex: MemoryLayout.size)

    let line = SCNGeometry(sources: [source], elements: [element])
    return SCNNode(geometry: line)
}

if you would like to update the line width or anything related to modifying properties of the drawn line, you'll want to use one of the openGL calls in SceneKit's rendering callback:

func renderer(aRenderer: SCNSceneRenderer, willRenderScene scene: SCNScene, atTime time: NSTimeInterval) {
    //Makes the lines thicker
    glLineWidth(20)
}