bubbles / files / src / physics / RigidBody.ts

RigidBody.ts

1	import { Vector2 } from './Vector2.js';
2
3	export interface RigidBodyOptions {
4	position: Vector2;
5	radius: number;
6	/** g/cm³ equivalent — water = 1.0; < 1 floats, > 1 sinks */
7	density: number;
8	/** Display label — emoji or short string */
9	label: string;
10	/** Optional pre-rendered texture drawn instead of label */
11	texture?: HTMLCanvasElement;
12	/** Permanent bodies are never evicted by the 12-body cap */
13	permanent?: boolean;
14	}
15
16	export class RigidBody {
17	position: Vector2;
18	velocity: Vector2;
19	readonly radius: number;
20	readonly density: number;
21	readonly label: string;
22	readonly texture: HTMLCanvasElement \| undefined;
23	readonly permanent: boolean;
24	/** Rotation angle in radians, for visual wobble */
25	angle: number = 0;
26	angularVelocity: number = 0;
27	/** Unique id for removal tracking */
28	readonly id: number;
29
30	private static _nextId = 0;
31
32	constructor(opts: RigidBodyOptions) {
33	this.position = opts.position.clone();
34	this.velocity = Vector2.zero();
35	this.radius = opts.radius;
36	this.density = opts.density;
37	this.label = opts.label;
38	this.texture = opts.texture;
39	this.permanent = opts.permanent ?? false;
40	this.id = RigidBody._nextId++;
41	}
42
43	get mass(): number {
44	return this.density * Math.PI * this.radius * this.radius;
45	}
46	}