试图弄清楚我如何创建一个以多边形为primitiveType的SCNGeometry,我的目标是添加多边形节点作为球体节点的子节点,并使其看起来像地图套件的MKPolygon,就像在这个例子中一样。
我目前的代码是:
//Take an arbitrary array of vectors
let vertices: [SCNVector3] = [
SCNVector3Make(-0.1304485, 0.551937, 0.8236193),
SCNVector3Make(0.01393811, 0.601815, 0.7985139),
SCNVector3Make(0.2971005, 0.5591929, 0.7739732),
SCNVector3Make(0.4516893, 0.5150381, 0.7285002),
SCNVector3Make(0.4629132, 0.4383712, 0.7704169),
SCNVector3Make(0.1333823, 0.5224985, 0.8421428),
SCNVector3Make(-0.1684743, 0.4694716, 0.8667254)]
//Does polygon shape require indices?
let indices: [Int] = [0,1,2,3,4,5,6]
let vertexSource = SCNGeometrySource(vertices: vertices)
let indexData = Data(bytes: indices, count: indices.count * MemoryLayout<Int>.size)
//Note!!! I get compiler error if primitiveCount is greater than 0
let element = SCNGeometryElement(data: indexData, primitiveType: .polygon, primitiveCount: 0, bytesPerIndex: MemoryLayout<Int>.size)
let geometry = SCNGeometry(sources: [vertexSource], elements: [element])
let material = SCNMaterial()
material.diffuse.contents = UIColor.purple.withAlphaComponent(0.75)
material.isDoubleSided = true
geometry.firstMaterial = material
let node = SCNNode(geometry: geometry)
当像这样使用SCNGeometryElement时,我得到一个空节点。