Merge pull request #143 from NateTheGreatt/perf/add-entity-pop

🐛 classic: Recycle entities without shift

Author: krispya

packages/classic/src/entity/Entity.ts

@@ -38,8 +38,23 @@ export const getGlobalSize = () => globalSize;
 
 // removed eids should also be global to prevent memory leaks
 const removed: number[] = [];
+const removedOut: number[] = [];
 const recycled: number[] = [];
 
+const dequeuFromRemoved = () => {
+	if (removedOut.length === 0) {
+		while (removed.length > 0) {
+			removedOut.push(removed.pop()!);
+		}
+	}
+	if (removedOut.length === 0) {
+		throw new Error('Queue is empty');
+	}
+	return removedOut.pop()!;
+};
+
+const getRemovedLength = () => removed.length + removedOut.length;
+
 const defaultRemovedReuseThreshold = 0.01;
 let removedReuseThreshold = defaultRemovedReuseThreshold;
 
@@ -48,6 +63,7 @@ export const resetGlobals = () => {
 	globalEntityCursor = 0;
 	removedReuseThreshold = defaultRemovedReuseThreshold;
 	removed.length = 0;
+	removedOut.length = 0;
 	recycled.length = 0;
 	queries.length = 0;
 	worlds.length = 0;
@@ -104,13 +120,17 @@ export const Prefab = defineComponent();
  * @returns {number} eid
  */
 export const addEntity = (world: World): number => {
-	const eid: number = world[$manualEntityRecycling]
-		? removed.length
-			? removed.shift()!
-			: globalEntityCursor++
-		: removed.length > Math.round(globalSize * removedReuseThreshold)
-		? removed.shift()!
-		: globalEntityCursor++;
+	let eid: number;
+
+	if (
+		(world[$manualEntityRecycling] && getRemovedLength() > 0) ||
+		(!world[$manualEntityRecycling] &&
+			getRemovedLength() > Math.round(globalSize * removedReuseThreshold))
+	) {
+		eid = dequeuFromRemoved();
+	} else {
+		eid = globalEntityCursor++;
+	}
 
 	if (world[$entitySparseSet].dense.length >= world[$size]) {
 		throw new Error('bitECS - max entities reached');
@@ -177,9 +197,9 @@ export const removeEntity = (world: World, eid: number) => {
 
 	// Remove entity from all queries
 	// TODO: archetype graph
-	world[$queries].forEach((q) => {
-		queryRemoveEntity(world, q, eid);
-	});
+	for (const query of world[$queries]) {
+		queryRemoveEntity(world, query, eid);
+	}
 
 	// Free the entity
 	if (world[$manualEntityRecycling]) recycled.push(eid);

packages/classic/test/integration/Entity.test.ts

@@ -41,6 +41,7 @@ describe('Entity Integration Tests', () => {
 		strictEqual(removed[1], 1);
 		strictEqual(removed[2], 2);
 	});
+
 	it('should recycle entity IDs after 1% have been removed by default', () => {
 		const world = createWorld();
 		const ents: number[] = [];
@@ -76,6 +77,7 @@ describe('Entity Integration Tests', () => {
 		eid = addEntity(world);
 		strictEqual(eid, 0);
 	});
+
 	it('should flush entity IDs', () => {
 		const world = createWorld();
 		enableManualEntityRecycling(world);
@@ -121,6 +123,7 @@ describe('Entity Integration Tests', () => {
 		eid = addEntity(world);
 		strictEqual(eid, 5);
 	});
+
 	it('should be able to configure % of removed entity IDs before recycle', () => {
 		const world = createWorld();