WIP

engine/lib/RingBuffer.ts

@@ -0,0 +1,25 @@
+export default class RingBuffer<T> {
+	size: number;
+	mask: number;
+	cursor: number;
+	buffer: Array<T>;
+
+	constructor(size: number, blueprint: T) {
+		if ((size & (size - 1)) !== 0) {
+			throw new Error("size must be a power of two");
+		}
+
+		this.size = size;
+		this.mask = size - 1;
+		this.cursor = 0;
+		this.buffer = [];
+
+		for (let i = 0; i < size; i++) {
+			this.buffer.push(structuredClone(blueprint));
+		}
+	}
+
+	next(): T {
+		return this.buffer[this.cursor++ & this.mask];
+	}
+}

engine/system/processPhysics.ts

@@ -1,9 +1,10 @@
 import type { Circle } from "#/engine/Circle.ts";
 import type MapProxy from "#/engine/lib/MapProxy.ts";
+import RingBuffer from "#/engine/lib/RingBuffer.ts";
 import type { Polygon } from "#/engine/Polygon.ts";
 import type { Rect } from "#/engine/Rect.ts";
 import $ from "#/engine/Scene.ts";
-import type { Vector } from "#/engine/Vector.ts";
+import { createVector, type Vector } from "#/engine/Vector.ts";
 
 const CIRCLE = 0;
 const RECT = 1;
@@ -13,49 +14,38 @@ type Shape = 0 | 1 | 2;
 
 export type Collider = {
 	shape: Shape;
+	collision: Collision;
 };
 
 export type Collision = {
 	id: string;
 };
 
-const collisions = new Map<string, Collision>();
-
-function check(
-	id: string,
-	collider: Collider,
-	position: Vector,
-	colliders: MapProxy<string, Collider>,
-): string | undefined {
-	for (const [oid, other] of colliders.entries()) {
-		if (oid !== id && other) {
-			return oid;
-		}
-	}
+export function createCollider(shape: Shape): Collider {
+	return {
+		shape,
+		collision: { id: "" },
+	};
 }
 
+const collisions = new RingBuffer(128, {
+	id: "",
+	normal: createVector(),
+});
+
 export function moveAndCollide(
 	id: string,
 	velocity: Vector,
 	delta: number,
-): Collision | undefined {
-	return collisions.get(id);
-}
-
-export function processPhysics(
-	ctx: CanvasRenderingContext2D,
-	delta: number,
 ): void {
 	const colliders = $<Collider>("collider")!;
-	const positions = $<Vector>("position")!;
 
-	for (const [id, collider] of colliders.entries()) {
-		const position = positions.get(id)!;
-		const target = check(id, collider.value, position.value, colliders);
-		if (target !== undefined) {
-			collisions.set(id, { id: target });
-		} else {
-			collisions.delete(id);
+	for (const [oid, _] of colliders.entries()) {
+		if (oid === id) {
+			continue;
 		}
+
+		const self = colliders.get(id)!.value;
+		self.collision.id = oid;
 	}
 }