update BVH

Author: ChrisShank

packages/geometry/__tests__/BoundingVolumeHierarchy.test.ts

@@ -36,8 +36,6 @@ describe('BoundingVolumeHierarchy', () => {
       width: 25,
       height: 25,
     });
-
-    expect(BVH.intersections(bvh, shapes[0], S.boundingBox(shapes[0])).length).toBe(0);
   });
 
   const shapes = [S.fromValues(0, 0, 10, 10), S.fromValues(15, 15, 10, 10), S.fromValues(5, 5, 10, 10)];
@@ -56,14 +54,16 @@ describe('BoundingVolumeHierarchy', () => {
   test('intersection', () => {
     const bvh = BVH.fromShapes([...shapes]);
 
-    const c1 = BVH.intersections(bvh, shapes[0], S.boundingBox(shapes[0]));
-    expect(c1.length).toBe(1);
+    const c1 = BVH.intersections(bvh, S.boundingBox(shapes[0]));
+    expect(c1.length).toBe(2);
+    expect(c1).toContain(shapes[0]);
     expect(c1).toContain(shapes[2]);
 
-    const c2 = BVH.intersections(bvh, shapes[2], S.boundingBox(shapes[2]));
-    expect(c2.length).toBe(2);
+    const c2 = BVH.intersections(bvh, S.boundingBox(shapes[2]));
+    expect(c2.length).toBe(3);
     expect(c2).toContain(shapes[0]);
     expect(c2).toContain(shapes[1]);
+    expect(c2).toContain(shapes[2]);
   });
 
   describe('nearest neighbor', () => {

packages/geometry/src/BoundingVolumeHierarchy.ts

@@ -76,13 +76,44 @@ export function fromShapes(shapes: Array<S.Shape2D>): BVHNode<S.Shape2D> {
   return constructBVHTree(leafNodes, 0, leafNodes.length - 1);
 }
 
-export function intersections<T>(root: BVHNode<T>, value: T, rect: R.Rect2D): T[] {
+export function fromElements(elements: Element[]): BVHNode<Element> {
+  if (elements.length === 0) {
+    return {
+      value: new Element(),
+      aabb: R.fromValues(),
+      mortonCode: -1,
+      isLeaf: true,
+      left: null,
+      right: null,
+    };
+  }
+
+  const leafNodes: BVHLeafNode<Element>[] = elements.map((el) => {
+    const aabb = el.getBoundingClientRect();
+
+    return {
+      value: el,
+      aabb,
+      mortonCode: V.mortonCode(R.center(aabb)),
+      isLeaf: true,
+      left: null,
+      right: null,
+    };
+  });
+
+  // Rectangles sorted in order of their morton codes.
+  leafNodes.sort((a, b) => a.mortonCode - b.mortonCode);
+
+  return constructBVHTree(leafNodes, 0, leafNodes.length - 1);
+}
+
+export function intersections<T>(root: BVHNode<T>, rect: R.Rect2D): T[] {
   const stack = [root];
   let node: BVHNode<T> | undefined;
   const collisions: T[] = [];
 
   while ((node = stack.pop())) {
-    if (value === node.value || !R.intersects(rect, node.aabb)) continue;
+    if (!R.intersects(rect, node.aabb)) continue;
 
     if (node.isLeaf) {
       collisions.push(node.value);
@@ -114,6 +145,10 @@ export function depthFirstTraverse<T>(root: BVHNode<T>, cb: (node: BVHNode<T>) =
   }
 }
 
+export function proximal<T>(root: BVHNode<T>, rect: R.Rect2D, proximity: number): T[] {
+  return intersections(root, R.expand(rect, proximity));
+}
+
 export function nearestShape(root: BVHNode<S.Shape2D>, shape: S.Shape2D, direction?: V.Vector2): S.Shape2D | undefined {
   const stack = [root];
   let node: BVHNode<S.Shape2D> | undefined;