miaoda-game-contact2d-core

Use this engine-neutral package when fast 2D circles can cross a target between fixed ticks. It returns the earliest time of impact, contact point, and normal without moving either object or applying collision response.

pnpm add miaoda-game-contact2d-core

import { sweepCircleCapsule } from 'miaoda-game-contact2d-core';

const hit = sweepCircleCapsule(
  { from: shuttle.previous, to: shuttle.position, radius: 3 },
  { start: racket.handle, end: racket.head, radius: 6 },
);

if (hit) game.handleRacketContact(hit);

Scope

• sweepCircles handles two linearly moving circles.
• sweepCircleSegment handles thin walls, nets, goals, and beams.
• sweepCircleCapsule handles thick segments such as rackets, bats, swords, rails, and rounded obstacles.
• sortContacts orders multiple results by impact fraction and stable ID.

targeting2d-core answers which targets overlap a range at one instant. kinematic2d-core owns swept-AABB actor movement and collision response. This package only calculates stateless continuous contacts and deliberately does not own a world, broadphase, position integration, bounce, damage, or scoring.

A capsule is static during one query. For a rapidly rotating rigid racket or bat, use the physics engine's CCD, substep the motion, or model its striking head as a moving circle; this package does not approximate angular sweep.

With Box2D, Planck, Matter, or another physics engine, prefer the engine's CCD for physics bodies. Use this package for engine-free simulations, prediction, headless tests, or explicit gameplay contacts, but never let both systems resolve the same body movement.