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-rw-r--r--src/Geometry/Geometry.js35
-rw-r--r--src/Geometry/Geometry.test.js48
2 files changed, 82 insertions, 1 deletions
diff --git a/src/Geometry/Geometry.js b/src/Geometry/Geometry.js
index 43f277f..6c296ad 100644
--- a/src/Geometry/Geometry.js
+++ b/src/Geometry/Geometry.js
@@ -122,6 +122,41 @@ class QTNode {
return false;
}
+ /* remove a node from the tree */
+ remove(point) {
+ if (this.aabb.contains(point)) {
+ switch(this.type) {
+ case QTNode.Empty:
+ break;
+
+ case QTNode.Leaf:
+ if (this.point.x === point.x && this.point.y === point.y) {
+ this.point = undefined;
+ this.type = QTNode.Empty;
+ }
+ break;
+
+ case QTNode.Branch:
+ for (let subnode of this.subnode) subnode.remove(point);
+ let numBranches = 0;
+ let numLeaves = 0;
+ for (let subnode of this.subnode) {
+ if (subnode.type === QTNode.Leaf) numLeaves += 1;
+ if (subnode.type === QTNode.Branch) numBranches += 1;
+ }
+ if (numBranches == 0 && numLeaves == 1) {
+ /* contract to leaf node */
+ this.type = QTNode.Empty; // start as Empty so insertion works correctly
+ for (let subnode of this.subnode) {
+ if (subnode.type == QTNode.Leaf) this.insert(subnode.point);
+ }
+ this.subnode = undefined;
+ }
+ break;
+ }
+ }
+ }
+
/* subdivide the node into four child nodes
*
* under normal circumstances, the user should not call this function --
diff --git a/src/Geometry/Geometry.test.js b/src/Geometry/Geometry.test.js
index 0b81438..1ec50f7 100644
--- a/src/Geometry/Geometry.test.js
+++ b/src/Geometry/Geometry.test.js
@@ -176,7 +176,53 @@ test('QTNode correctly returns points in region', () => {
};
bf_points.sort(compare);
qt_points.sort(compare);
- assert.deepEqual(bf_points, qt_points);});
+ assert.deepEqual(bf_points, qt_points);
+});
+
+
+test('QTNode correctly removes immediate child point', () => {
+ const node = new QTNode(0, 0, 1, 1);
+
+ const pt = randomPoint();
+ node.insert(pt);
+ assert.deepEqual(node.type, QTNode.Leaf);
+
+ const pt2 = randomPoint();
+ node.remove(pt2);
+ assert.deepEqual(node.type, QTNode.Leaf);
+ assert.deepEqual(node.point, pt);
+
+ node.remove(pt);
+ assert.deepEqual(node.type, QTNode.Empty);
+ assert.equal(node.point, undefined);
+});
+
+
+test('QTNode correctly removes point from branch', () => {
+ for (let i=0; i<100; i++) {
+ const node = new QTNode(0, 0, 1, 1);
+
+ const pt1 = randomPoint();
+ const pt2 = randomPoint();
+ const pt3 = randomPoint();
+
+ node.insert(pt1); node.insert(pt2); node.insert(pt3);
+
+ assert.deepEqual(node.type, QTNode.Branch);
+
+ node.remove(pt1);
+ // should still be a branch because there are two child points yet
+ assert.deepEqual(node.type, QTNode.Branch);
+
+ node.remove(pt2);
+ // just one now, should be a leaf
+ assert.deepEqual(node.type, QTNode.Leaf);
+
+ node.remove(pt3);
+ // empty
+ assert.deepEqual(node.type, QTNode.Empty);
+ }
+});
test('QuadTree correctly finds closest point for 10,000 random points', () => {