From 31ae9d94d528d05cbb52794082918ef12c733e09 Mon Sep 17 00:00:00 2001
From: Schluffe <schluffe@cachyos>
Date: Tue, 17 Mar 2026 23:26:16 +0100
Subject: [PATCH] WIP

---
 engine/lib/RingBuffer.ts        | 25 +++++++++++++++++
 engine/system/processPhysics.ts | 48 +++++++++++++--------------------
 game/entities/hero/entity.ts    |  8 +++---
 game/entities/portal/entity.ts  |  3 ++-
 main.ts                         |  3 ---
 5 files changed, 51 insertions(+), 36 deletions(-)
 create mode 100644 engine/lib/RingBuffer.ts

diff --git a/engine/lib/RingBuffer.ts b/engine/lib/RingBuffer.ts
new file mode 100644
index 0000000..9d5c95b
--- /dev/null
+++ b/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];
+	}
+}
diff --git a/engine/system/processPhysics.ts b/engine/system/processPhysics.ts
index 5a1b749..f77ea1e 100644
--- a/engine/system/processPhysics.ts
+++ b/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;
 	}
 }
diff --git a/game/entities/hero/entity.ts b/game/entities/hero/entity.ts
index 64e8379..03aa6f0 100644
--- a/game/entities/hero/entity.ts
+++ b/game/entities/hero/entity.ts
@@ -10,6 +10,7 @@ import {
 } from "#/engine/Sprite.ts";
 import {
 	type Collider,
+	createCollider,
 	moveAndCollide,
 } from "#/engine/system/processPhysics.ts";
 import { createVector, type Vector } from "#/engine/Vector.ts";
@@ -23,12 +24,13 @@ const process = defineEntity("hero", {
 	sprite: createSprite(idleSrc),
 	animation: createSpriteAnimation(500, 2),
 	velocity: createVector(),
-	collider: createCircle(createVector(), 8),
+	collider: createCollider(0),
 });
 
 process((id, delta) => {
 	const position = $<Vector>("position").get(id)!.value;
 	const velocity = $<Vector>("velocity").get(id)!.value;
+	const collider = $<Collider>("collider").get(id)!.value;
 
 	if (pointer.isDown) {
 		position.x = pointer.position.x;
@@ -46,6 +48,6 @@ process((id, delta) => {
 	velocity.x = 0;
 	velocity.y = 0;
 
-	const collision = moveAndCollide(id, velocity, delta);
-	// console.log(collision);
+	moveAndCollide(id, velocity, delta);
+	console.log(collider.collision.id);
 });
diff --git a/game/entities/portal/entity.ts b/game/entities/portal/entity.ts
index 83f6feb..2524113 100644
--- a/game/entities/portal/entity.ts
+++ b/game/entities/portal/entity.ts
@@ -5,6 +5,7 @@ import {
 	createSpriteAnimation,
 	defineSpriteSheet,
 } from "#/engine/Sprite.ts";
+import { createCollider } from "#/engine/system/processPhysics.ts";
 import { createVector } from "#/engine/Vector.ts";
 import portal from "#/game/assets/portal.png";
 
@@ -14,5 +15,5 @@ defineEntity("portal", {
 	position: createVector(),
 	sprite: createSprite(portalSrc),
 	animation: createSpriteAnimation(400, 0),
-	collider: createCircle(createVector(), 8),
+	collider: createCollider(0),
 });
diff --git a/main.ts b/main.ts
index a072b7c..964e0b9 100644
--- a/main.ts
+++ b/main.ts
@@ -3,7 +3,6 @@ import { listenPointer } from "#/engine/Pointer.ts";
 import { currentScene, setScene } from "#/engine/Scene.ts";
 import { animateSprites } from "#/engine/system/animateSprites.ts";
 import { drawSprites } from "#/engine/system/drawSprites.ts";
-import { processPhysics } from "#/engine/system/processPhysics.ts";
 import {
 	initViewport,
 	resetCtx,
@@ -20,8 +19,6 @@ function animate(timestamp: number): void {
 	resetCtx();
 	currentScene.process(viewport.ctx, delta);
 
-	processPhysics(viewport.ctx, delta);
-
 	animateSprites(delta);
 	drawSprites(viewport.ctx);