perf: parallel-producer spike + bank the serial collision win

mise.toml

@@ -1,3 +1,3 @@
 [tools]
-pnpm = "11.15.1"
-node = "26.5.0"
+pnpm = "12.12.1"
+node = "26.11.1"

packages/examples/src/demos/shmup/systems/collision-system.ts

@@ -1,4 +1,3 @@
-import { intersects } from "#/lib/collision/aabb.ts";
 import { World } from "objecs";
 import { Config } from "../config.ts";
 import { EnemyType } from "../constants.ts";
@@ -31,6 +30,16 @@ export function collisionSystemFactory({
 				continue;
 			}
 
+			const { boxCollider, transform } = entity;
+			const collisionLayer = entity.collisionLayer;
+
+			// Hoist the outer entity's bounds out of the inner loop. The previous
+			// version recomputed these for every otherEntity.
+			const left = transform.position.x + boxCollider.offsetX;
+			const top = transform.position.y + boxCollider.offsetY;
+			const right = left + boxCollider.width;
+			const bottom = top + boxCollider.height;
+
 			for (const otherEntity of collidables.entities) {
 				if (entity === otherEntity) {
 					continue;
@@ -42,42 +51,28 @@ export function collisionSystemFactory({
 
 				// Make sure entityA's collision layer is a subset of entityB's
 				// collision mask
-				if (
-					(entity.collisionLayer & otherEntity.collisionMask) !==
-					entity.collisionLayer
-				) {
+				if ((collisionLayer & otherEntity.collisionMask) !== collisionLayer) {
 					continue;
 				}
 
-				const { boxCollider, transform } = entity;
-
-				const { boxCollider: otherBoxCollider, transform: otherTransform } =
-					otherEntity;
-
-				const x = transform.position.x + boxCollider.offsetX;
-				const y = transform.position.y + boxCollider.offsetY;
-				const otherX = otherTransform.position.x + otherBoxCollider.offsetX;
-				const otherY = otherTransform.position.y + otherBoxCollider.offsetY;
-
-				const aabb = {
-					position: {
-						x,
-						y,
-					},
-					width: boxCollider.width,
-					height: boxCollider.height,
-				};
-
-				const otherAabb = {
-					position: {
-						x: otherX,
-						y: otherY,
-					},
-					width: otherBoxCollider.width,
-					height: otherBoxCollider.height,
-				};
-
-				if (!intersects(aabb, otherAabb)) {
+				const otherBoxCollider = otherEntity.boxCollider;
+				const otherTransform = otherEntity.transform;
+
+				const otherLeft = otherTransform.position.x + otherBoxCollider.offsetX;
+				const otherTop = otherTransform.position.y + otherBoxCollider.offsetY;
+
+				// Inlined AABB intersection test. The previous version allocated
+				// two temp AABB literals (four objects) on every pair check; this
+				// reads the hoisted bounds directly. Same comparison as
+				// `intersects()` in lib/collision/aabb.ts.
+				if (
+					!(
+						left < otherLeft + otherBoxCollider.width &&
+						right > otherLeft &&
+						top < otherTop + otherBoxCollider.height &&
+						bottom > otherTop
+					)
+				) {
 					continue;
 				}
 

packages/examples/vite.config.ts

@@ -15,7 +15,7 @@ const demoInputs = await fs
 
 export default defineConfig({
 	build: {
-		rollupOptions: {
+		rolldownOptions: {
 			input: {
 				main: resolve(__dirname, "index.html"),
 				...demoInputs,

packages/perf-proofs/README.md

@@ -54,3 +54,20 @@ node --expose-gc src/object/hasown-vs-undefined-check.ts
 ### function/
 
 - **call-vs-direct-invocation** — `Function.prototype.call()` vs direct invocation in tight loops. Maps to `EntityCollection.forEach()`.
+
+### worker/
+
+Spike category — evaluating parallel producer systems (Worker threads +
+shared read-only snapshots). Unlike the other categories, these benchmarks
+depend on the built `objecs` package and gate on correctness assertions
+before reporting timings.
+
+- **collision-serial** — three serial collision kernels (faithful shmup replica,
+  precomputed, packed SoA) establishing the baseline any Worker variant must
+  beat. Maps to `packages/examples/src/demos/shmup/systems/collision-system.ts`.
+
+See [`src/worker/README.md`](src/worker/README.md) for results and status.
+
+```bash
+pnpm --filter perf-proofs start:worker
+```

packages/perf-proofs/package.json

@@ -4,17 +4,19 @@
 	"version": "0.0.0",
 	"type": "module",
 	"scripts": {
-		"start": "for f in $(find src -name '*.ts' | sort); do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
+		"start": "for f in $(find src -name '*.ts' -not -path '*/lib/*' | sort); do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
 		"start:object": "for f in src/object/*.ts; do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
 		"start:array": "for f in src/array/*.ts; do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
 		"start:map-set": "for f in src/map-set/*.ts; do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
 		"start:set": "for f in src/set/*.ts; do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
 		"start:iteration": "for f in src/iteration/*.ts; do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
 		"start:function": "for f in src/function/*.ts; do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
+		"start:worker": "pnpm --filter objecs build && for f in src/worker/*.ts; do echo \"\\n--- $f ---\"; node --expose-gc \"$f\"; done",
 		"typecheck": "tsc --noEmit"
 	},
 	"dependencies": {
-		"mitata": "^1.0.34"
+		"mitata": "^1.0.34",
+		"objecs": "workspace:*"
 	},
 	"devDependencies": {
 		"@types/node": "^26.1.1",