create octree algorithm

Author: JaapWijnen

Diff for: Octree/Octree.playground/Contents.swift

@@ -0,0 +1,33 @@
+//: Playground - noun: a place where people can play
+
+import UIKit
+import simd
+
+let boxMin = vector_double3(0, 2, 6)
+let boxMax = vector_double3(5, 10, 9)
+let box = Box(boxMin: boxMin, boxMax: boxMax)
+var octree = Octree<Int>(boundingBox: box, minimumCellSize: 5.0)
+var five = octree.add(5, at: vector_double3(3,4,8))
+octree.add(8, at: vector_double3(3,4,8.2))
+octree.add(10, at: vector_double3(3,4,8.2))
+octree.add(7, at: vector_double3(2,5,8))
+octree.add(2, at: vector_double3(1,6,7))
+
+var cont = octree.elements(at: vector_double3(3,4,8.2))
+octree.remove(8)
+octree.elements(at: vector_double3(3,4,8))
+
+let boxMin2 = vector_double3(1,3,7)
+let boxMax2 = vector_double3(4,9,8)
+let box2 = Box(boxMin: boxMin2, boxMax: boxMax2)
+box.isContained(in: box2)
+box.intersects(box2)
+
+let boxMin3 = vector_double3(3,8,8)
+let boxMax3 = vector_double3(10,12,20)
+let box3 = Box(boxMin: boxMin3, boxMax: boxMax3)
+box3.intersects(box3)
+
+octree.elements(in: box)
+octree.elements(in: box2)
+print(octree)