Added KD tree

Runtime/KDTree/KDQuery/QueryRadius.cs

@@ -0,0 +1,131 @@
+/*MIT License
+
+Copyright(c) 2018 Vili Volčini / viliwonka
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+using System.Collections.Generic;
+using UnityEngine;
+using System;
+
+namespace DataStructures.ViliWonka.KDTree {
+
+    public partial class KDQuery {
+
+        /// <summary>
+        /// Search by radius method.
+        /// </summary>
+        /// <param name="tree">Tree to do search on</param>
+        /// <param name="queryPosition">Position</param>
+        /// <param name="queryRadius">Radius</param>
+        /// <param name="resultIndices">Initialized list, cleared.</param>
+        public void Radius(KDTree tree, Vector3 queryPosition, float queryRadius, List<int> resultIndices) {
+
+            Reset();
+
+            Vector3[] points = tree.Points;
+            int[] permutation = tree.Permutation;
+
+            float squaredRadius = queryRadius * queryRadius;
+
+            var rootNode = tree.RootNode;
+
+            PushToQueue(rootNode, rootNode.bounds.ClosestPoint(queryPosition));
+
+            KDQueryNode queryNode = null;
+            KDNode node = null;
+
+            // KD search with pruning (don't visit areas which distance is more away than range)
+            // Recursion done on Stack
+            while(LeftToProcess > 0) {
+
+                queryNode = PopFromQueue();
+                node = queryNode.node;
+
+                if(!node.Leaf) {
+
+                    int partitionAxis = node.partitionAxis;
+                    float partitionCoord = node.partitionCoordinate;
+
+                    Vector3 tempClosestPoint = queryNode.tempClosestPoint;
+
+                    if((tempClosestPoint[partitionAxis] - partitionCoord) < 0) {
+
+                        // we already know we are inside negative bound/node,
+                        // so we don't need to test for distance
+                        // push to stack for later querying
+
+                        // tempClosestPoint is inside negative side
+                        // assign it to negativeChild
+                        PushToQueue(node.negativeChild, tempClosestPoint);
+
+                        tempClosestPoint[partitionAxis] = partitionCoord;
+
+                        float sqrDist = Vector3.SqrMagnitude(tempClosestPoint - queryPosition);
+
+                        // testing other side
+                        if(node.positiveChild.Count != 0
+                        && sqrDist <= squaredRadius) {
+
+                            PushToQueue(node.positiveChild, tempClosestPoint);
+                        }
+                    }
+                    else {
+
+                        // we already know we are inside positive bound/node,
+                        // so we don't need to test for distance
+                        // push to stack for later querying
+
+                        // tempClosestPoint is inside positive side
+                        // assign it to positiveChild
+                        PushToQueue(node.positiveChild, tempClosestPoint);
+
+                        // project the tempClosestPoint to other bound
+                        tempClosestPoint[partitionAxis] = partitionCoord;
+
+                        float sqrDist = Vector3.SqrMagnitude(tempClosestPoint - queryPosition);
+
+                        // testing other side
+                        if(node.negativeChild.Count != 0
+                        && sqrDist <= squaredRadius) {
+
+                            PushToQueue(node.negativeChild, tempClosestPoint);
+                        }
+                    }
+                }
+                else {
+
+                    // LEAF
+                    for(int i = node.start; i < node.end; i++) {
+
+                        int index = permutation[i];
+
+                        if(Vector3.SqrMagnitude(points[index] - queryPosition) <= squaredRadius) {
+
+                            resultIndices.Add(index);
+                        }
+                    }
+
+                }
+            }
+        }
+
+    }
+}