rootandClaude Fable 5.1
0a59513b74
- Asset type 'collider' (box/circle) placed as child of a body object - 'Add collider' shortcut (hierarchy context menu + inspector) - CollisionSystem with enter/stay/exit pairs, sibling colliders excluded - Nodes: On collision enter/stay/exit, Is touching - Green outline in edit mode, hidden in play Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
76 lines
2.8 KiB
TypeScript
76 lines
2.8 KiB
TypeScript
import { colliderShape, shapesOverlap } from '../../core/properties/collider';
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import type { Entity } from '../Entity';
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import type { World } from '../World';
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import type { System } from './System';
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/** Two collider entities that overlap (or overlapped) – always the same pair order per key. */
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export interface CollisionPair {
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a: Entity;
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b: Entity;
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}
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/**
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* Detects overlaps between collider entities once per tick and sorts them into enter /
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* stay / exit lists for the frame. Detection only – nothing is pushed apart. Colliders
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* of the same body (same parent) never collide with each other. Runs before the
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* BehaviorSystem so graphs see this frame's events.
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*/
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export class CollisionSystem implements System {
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enters: CollisionPair[] = [];
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stays: CollisionPair[] = [];
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exits: CollisionPair[] = [];
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private previous = new Map<string, CollisionPair>();
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update(world: World): void {
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const colliders = world.entities.filter((e) => e.type === 'collider');
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const current = new Map<string, CollisionPair>();
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for (let i = 0; i < colliders.length; i++) {
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for (let j = i + 1; j < colliders.length; j++) {
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const a = colliders[i]!;
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const b = colliders[j]!;
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if (bodyOf(a) === bodyOf(b)) continue;
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if (this.overlapping(world, a, b)) current.set(`${a.id}|${b.id}`, { a, b });
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}
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}
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this.enters = [];
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this.stays = [];
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this.exits = [];
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for (const [key, pair] of current) (this.previous.has(key) ? this.stays : this.enters).push(pair);
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for (const [key, pair] of this.previous) if (!current.has(key)) this.exits.push(pair);
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this.previous = current;
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}
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stop(): void {
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this.previous = new Map();
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this.enters = [];
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this.stays = [];
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this.exits = [];
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}
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/** Live test of two collider entities (world positions applied). */
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overlapping(world: World, a: Entity, b: Entity): boolean {
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return shapesOverlap(colliderShape(a.props, world.worldPosition(a)), colliderShape(b.props, world.worldPosition(b)));
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}
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/** Whether any collider of `a` overlaps any collider of `b` (see `collidersOf`). */
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touching(world: World, a: Entity, b: Entity): boolean {
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for (const ca of collidersOf(world, a)) {
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for (const cb of collidersOf(world, b)) {
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if (ca !== cb && this.overlapping(world, ca, cb)) return true;
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}
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}
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return false;
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}
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}
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/** The object a collider belongs to: its parent, or the collider itself when top-level. */
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export function bodyOf(collider: Entity): Entity {
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return collider.parent ?? collider;
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}
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/** A collider stands for itself; any other entity stands for its direct collider children. */
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export function collidersOf(world: World, entity: Entity): Entity[] {
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if (entity.type === 'collider') return [entity];
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return world.childrenOf(entity).filter((e) => e.type === 'collider');
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}
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