Collision

Efficient collision detection with multiple shape types and event callbacks.

Imports

import { ElementObject } from "@snap-engine/core";
import {
  CollisionEngine,
  RectCollider,
  CircleCollider,
  PointCollider,
} from "@snap-engine/core/collision";

Setup

const engine = new Engine();
engine.setCollisionEngine(new CollisionEngine());

Basic Usage

const player = new ElementObject(engine);
player.element = document.getElementById("player");

const obstacle = new ElementObject(engine);
obstacle.element = document.getElementById("obstacle");

const playerCollider = new CircleCollider(engine, player, 0, 0, 25);
player.addCollider(playerCollider);

const obstacleCollider = new RectCollider(engine, obstacle, 0, 0, 100, 50);
obstacle.addCollider(obstacleCollider);

playerCollider.event.collider.onBeginContact = (self, other) => {
  console.log("Collision started", self, other);
};

playerCollider.event.collider.onEndContact = (self, other) => {
  console.log("Collision ended", self, other);
};

Collider Constructors

const rect = new RectCollider(engine, object, -50, -25, 100, 50);
object.addCollider(rect);

const circle = new CircleCollider(engine, object, 0, 0, 30);
object.addCollider(circle);

const point = new PointCollider(engine, object, 0, 0);
object.addCollider(point);

Collision Events

collider.event.collider.onBeginContact = (self, other) => {
  console.log("started", other.parent);
};

collider.event.collider.onCollide = (self, other) => {
  console.log("still colliding");
};

collider.event.collider.onEndContact = (self, other) => {
  console.log("ended");
};

Event	Description
`onBeginContact`	Called once when two colliders first touch.
`onCollide`	Called every frame while two colliders overlap.
`onEndContact`	Called once when two colliders stop touching.

Public API

API	Description
`new CollisionEngine()`	Creates a collision manager.
`collisionEngine.addObject(collider)`	Registers a collider. Usually called through `object.addCollider()`.
`collisionEngine.removeObject(id)`	Removes a collider by symbol id.
`collisionEngine.detectCollisions()`	Runs collision detection.
`collisionEngine.isIntersecting(a, b)`	Checks two colliders directly.
`new RectCollider(engine, parent, localX, localY, width, height)`	Creates a rectangular collider.
`new CircleCollider(engine, parent, localX, localY, radius)`	Creates a circular collider.
`new PointCollider(engine, parent, localX, localY)`	Creates a point collider.
`collider.getWorldBoundsSnapshot()`	Returns current world bounds.
`collider.isCollidingWith(other)`	Checks whether two colliders are currently touching.
`collider.currentCollisions`	Current collision set.
`collider.destroy()`	Removes the collider from its parent and collision engine.