Raycast and catch a trigger in 3D

Two ways to ask the physics world a question. app.physics.raycast is a poll: an origin, a direction and a distance in, and the first entity, point, normal and distance out. A trigger volume is a push: a collider with isTrigger: true reports every body that enters or leaves it to the scripts on its own entity, through onTriggerEnter and onTriggerExit.

Both need one completed fixed step first — Havok builds its broadphase there — so a query before app.step throws IGX-0902. Prefer triggers for gameplay: @babylonjs/[email protected] reports collisions with no body identity, so collision.other is null, while a trigger event always carries both entities.

Event objects are pooled and reused for every event of a step, so copy anything you keep.

typescript

import { LayerMask, Script, createApp, u32 } from "@ignifx/core";import { BoxCollider, Rigidbody, SphereCollider, physics } from "@ignifx/physics";import type { ScriptCallbacks } from "@ignifx/core";import type { TriggerEvent } from "@ignifx/physics";/** Counts the bodies that walk into the volume this script shares an entity with. */class Zone extends Script.define({ visitors: u32(0) }) implements ScriptCallbacks {  static typeId = "recipes/Zone";  onTriggerEnter(trigger: TriggerEvent): void {    this.visitors += 1;    this.app.log.info("entered:", trigger.other?.name ?? "something", "visitors:", this.visitors);  }  onTriggerExit(trigger: TriggerEvent): void {    this.app.log.info("left:", trigger.other?.name ?? "something");  }}const app = await createApp({ headless: true, extensions: [physics()] });app.registerComponents([Zone]);await app.start();app.world.createEntity("Floor", { position: { x: 0, y: -0.5, z: 0 } }).addComponent(BoxCollider, {  size: { x: 20, y: 1, z: 20 },});const zone = app.world.createEntity("Zone", { position: { x: 0, y: 1, z: 0 } });zone.addComponent(BoxCollider, { size: { x: 4, y: 2, z: 4 }, isTrigger: true });zone.addComponent(Zone);const ball = app.world.createEntity("Ball", { position: { x: 0, y: 6, z: 0 } });ball.addComponent(SphereCollider, { radius: 0.4 });ball.addComponent(Rigidbody, { mass: 1 });// Bodies are built at the start of the next fixed step, and the broadphase with them.app.step(1 / 60);// The ray falls straight through the trigger volume it passes: `hitTriggers` defaults to false.const hit = app.physics.raycast({ x: 1.5, y: 8, z: 0 }, { x: 0, y: -1, z: 0 }, 20, {  layerMask: LayerMask.everything(),  hitTriggers: false,});if (hit !== null) {  app.log.info("ray hit:", hit.entity.name, "at y:", hit.point.y, "distance:", hit.distance);}// The ball drops into the volume and rests there, so `onTriggerEnter` fires once and no exit does.for (let step = 0; step < 120; step += 1) {  app.step(1 / 60);}app.log.info("visitors:", zone.getComponent(Zone)?.visitors ?? 0);app.dispose();

Source: examples/recipes/raycast-and-trigger-3d/main.ts