1 files changed, 259 insertions, 0 deletions
diff --git a/src/modules/Geometry.test.js b/src/modules/Geometry.test.js
new file mode 100644
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--- /dev/null
+++ b/src/modules/Geometry.test.js
@@ -0,0 +1,259 @@
+import { test, assert } from './test-assert.js';
+import { AABB, QTNode, QuadTree } from './Geometry.js';
+
+const RUN_BENCHMARKS = false;
+
+
+test('AABB correctly contains/excludes points', () => {
+	const box = new AABB(0, 0, 1, 1);
+
+	// interior
+	assert.ok(box.contains({ x: 0.5, y: 0.5 }));
+
+	// upper left
+	assert.ok(!box.contains({ x: -1, y: -1 }));
+
+	// above
+	assert.ok(!box.contains({ x: 0.5, y: -1}));
+
+	// upper right
+	assert.ok(!box.contains({ x: 2, y: -1 }));
+
+	// left
+	assert.ok(!box.contains({ x: -1, y: 0.5 }));
+
+	// right
+	assert.ok(!box.contains({ x: 2, y: 0.5}));
+
+	// lower left
+	assert.ok(!box.contains({ x: -1, y: 2 }));
+
+	// below 
+	assert.ok(!box.contains({ x: 0.5, y: 2}));
+
+	// lower right
+	assert.ok(!box.contains({ x: 2, y: 2 }));
+});
+
+
+test('AABB correctly intersects other AABBs', () => {
+	const box = new AABB(1, 1, 4, 4);
+
+	// interior
+	assert.ok(box.intersects(new AABB(2, 2, 2, 2,)));
+
+	// upper left
+	assert.ok(box.intersects(new AABB(0, 0, 4, 4)));
+	assert.ok(!box.intersects(new AABB(0, 0, 0.5, 0.5)));
+
+	// above
+	assert.ok(box.intersects(new AABB(2, 0, 2, 2)));
+	assert.ok(!box.intersects(new AABB(2, 0, 2, 0.5)));
+
+	// upper right
+	assert.ok(box.intersects(new AABB(2, 0, 4, 2)));
+	assert.ok(!box.intersects(new AABB(6, 0, 4, 2)));
+
+	// left
+	assert.ok(box.intersects(new AABB(0, 2, 2, 2)));
+	assert.ok(!box.intersects(new AABB(0, 2, 0.5, 2)));
+
+	// right
+	assert.ok(box.intersects(new AABB(4, 2, 2, 2)));
+	assert.ok(!box.intersects(new AABB(6, 2, 2, 2)));
+
+	// lower left
+	assert.ok(box.intersects(new AABB(0, 4, 4, 4)));
+	assert.ok(!box.intersects(new AABB(0, 6, 0.5, 0.5)));
+
+	// below
+	assert.ok(box.intersects(new AABB(2, 4, 2, 2)));
+	assert.ok(!box.intersects(new AABB(2, 6, 2, 0.5)));
+
+	// lower right
+	assert.ok(box.intersects(new AABB(2, 4, 4, 2)));
+	assert.ok(!box.intersects(new AABB(6, 6, 4, 2)));
+});
+
+
+test('AABB correctly handles points at the edges', () => {
+	const box = new AABB(0, 0, 1, 1);
+
+	assert.ok(box.contains({ x: 0, y: 0 }));
+	assert.ok(box.contains({ x: 0.5, y: 0 }));
+	assert.ok(box.contains({ x: 0, y: 0.5 }));
+
+	// bad corners
+	assert.ok(!box.contains({ x: 1, y: 0 }));
+	assert.ok(!box.contains({ x: 0, y: 1 }));
+	assert.ok(!box.contains({ x: 1, y: 1 }));
+
+	// bad edges
+	assert.ok(!box.contains({ x: 1, y: 0.5 }));
+	assert.ok(!box.contains({ x: 0.5, y: 1 }));
+});
+
+
+test('QTNode correctly inserts points', () => {
+	const node = new QTNode(0, 0, 1, 1);
+	assert.equal(node.type.toString(), 'QTNode.Empty');
+
+	let result = node.insert({ x: -1, y: -1 }); // out of range, should not insert
+	assert.ok(!result);
+	assert.equal(node.type.toString(), 'QTNode.Empty');
+
+	result = node.insert({ x: 0.5, y: 0.5 }); // in range
+	assert.ok(result);
+	assert.equal(node.type.toString(), 'QTNode.Leaf');
+	assert.deepEqual(node.point, { x: 0.5, y: 0.5 });
+});
+
+
+test('QTNode correctly subdivides', () => {
+	const node = new QTNode(0, 0, 2, 2);
+	assert.ok(!node.subnode);
+	node.subdivide();
+	assert.equal(node.subnode.length, 4);
+
+	assert.deepEqual(node.subnode[0], new QTNode(0, 0, 1, 1));
+	assert.deepEqual(node.subnode[1], new QTNode(1, 0, 1, 1));
+	assert.deepEqual(node.subnode[2], new QTNode(0, 1, 1, 1));
+	assert.deepEqual(node.subnode[3], new QTNode(1, 1, 1, 1));
+});
+
+
+test('QTNode correctly inserts multiple points', () => {
+	const node = new QTNode(0, 0, 2, 2);
+	
+	const p0 = { x: 1, y: 1 };
+	const p1 = { x: 0.5, y: 0.5 };
+	const oob = { x: 10, y: 15 };
+
+	assert.ok(node.insert(p0));
+	assert.ok(node.insert(p1));
+	assert.ok(!node.insert(oob));
+
+	assert.equal(node.type.toString(), 'QTNode.Branch');
+	
+	assert.equal(node.subnode[0].type.toString(), 'QTNode.Leaf');
+	assert.deepEqual(node.subnode[0].point, p1);
+
+	assert.equal(node.subnode[1].type.toString(), 'QTNode.Empty');
+	assert.equal(node.subnode[2].type.toString(), 'QTNode.Empty');
+
+	assert.equal(node.subnode[3].type.toString(), 'QTNode.Leaf');
+assert.deepEqual(node.subnode[3].point, p0);
+});
+
+
+const randomPoint = () => ({ x: Math.random(), y: Math.random() });
+
+
+test('QTNode correctly returns points in region', () => {
+	const node = new QTNode(0, 0, 1, 1);
+	let points = [];
+	for (let i=0; i<100; i++) {
+		const pt = randomPoint();
+		node.insert(pt);
+		points.push(pt);
+	}
+
+	const pointsInRegion = aabb => {
+		let pts = [];
+		for (let pt of points) {
+			if (aabb.contains(pt)) pts.push(pt);
+		}
+		return pts;
+	};
+
+	const region = new AABB(0.25, 0.25, 0.5, 0.5);
+	let bf_points = pointsInRegion(region);
+	let qt_points = node.getPointsInRegion(region);
+	const compare = (a, b) => {
+		if (a.x == b.x)
+			return b.y - a.y;
+		return b.x - a.x;
+	};
+	bf_points.sort(compare);
+	qt_points.sort(compare);
+	assert.deepEqual(bf_points, qt_points);});
+
+
+test('QuadTree correctly finds closest point for 10,000 random points', () => {
+	const tree = new QuadTree(1, 1);
+
+	let points = [];
+	for (let i=0; i<10000; i++) {
+		const pt = randomPoint();
+		tree.insert(pt);
+		points.push(pt);
+	}
+	
+	const distance = (a, b) => Math.sqrt((a.x - b.x)**2 + (a.y - b.y)**2);
+	const bf_closest = a => {
+		let closest = null;
+		let min_dist = 1000;
+		for (let b of points) {
+			let d = distance(a, b);
+			if (d < min_dist) {
+				min_dist = d;
+				closest = b;
+			}
+		}
+		return closest;
+	}
+
+	for (let i=0; i<10000; i++) {
+		const pt = randomPoint();
+		assert.deepEqual(bf_closest(pt), tree.closest(pt));
+	}
+});
+
+
+function benchmark(desc, f, iterations) {
+	process.stdout.write(`${desc}: `);
+	const start = process.uptime();
+	for (let i=0; i<iterations; i++) f();
+	const elapsed = process.uptime() - start;
+	console.log(`${elapsed} seconds`);
+}
+
+const closest_benchmark = () => {
+	const n_points = 1e5;
+	const iterations = 1e4;
+	console.log(`> benchmark get closest of ${n_points} random points ${iterations} times`);
+
+	const tree = new QuadTree(1, 1);
+	let points = [];
+	for (let i=0; i<n_points; i++) {
+		const pt = randomPoint();
+		tree.insert(pt);
+		points.push(pt);
+	}
+
+	const distance = (a, b) => Math.sqrt((a.x - b.x)**2 + (a.y - b.y)**2);
+	const bf_closest = a => {
+		let closest = null;
+		let min_dist = 1000;
+		for (let b of points) {
+			let d = distance(a, b);
+			if (d < min_dist) {
+				min_dist = d;
+				closest = b;
+			}
+		}
+		return closest;
+	}
+
+	benchmark('\tbrute force', () => {
+		const pt = randomPoint();
+		bf_closest(pt);
+	}, iterations);
+
+	benchmark('\tquadtree', () => {
+		const pt = randomPoint();
+		tree.closest(pt);
+	}, iterations);
+}
+if (RUN_BENCHMARKS)
+	closest_benchmark();