feuerwerk/tests/core/raycast.test.ts

import { beforeAll, describe, expect, it } from 'vitest';
import { CreateAssetCommand, SetAssetPropertyCommand } from '../../src/core/commands/assetCommands';
import { AddColliderCommand } from '../../src/core/commands/colliderCommands';
import { SetOverrideCommand } from '../../src/core/commands/sceneObjectCommands';
import { PaintTilesCommand } from '../../src/core/commands/tilemapCommands';
import type { TilemapAsset } from '../../src/core/model/Asset';
import {
  ALL_LAYERS,
  COLLIDES_WITH_KEY,
  COLLISION_LAYER_KEY,
  maskWith,
} from '../../src/core/model/collisionLayers';
import { IDENTITY, type Mat } from '../../src/core/model/matrix';
import type { PropertyValue, Vec2 } from '../../src/core/model/Properties';
import { findAsset } from '../../src/core/model/Project';
import { TILE_SOLID_KEY } from '../../src/core/model/tile';
import { TILEMAP_COLUMNS_KEY, TILEMAP_ROWS_KEY } from '../../src/core/model/tilemap';
import { colliderShape, type ColliderShape } from '../../src/core/properties/collider';
import { RAY_LAYERS_PARAM } from '../../src/core/graph/nodes/action/Raycast';
import { rayCast } from '../../src/core/properties/ray';
import { loadPhysics } from '../../src/runtime/physics/engine';
import { RAY_SHOWN } from '../../src/runtime/World';
import {
  COLLISION_SYSTEMS,
  graphEditor,
  makeBehavior,
  makeSpriteScene,
  place,
  type SceneFixture,
  startWorld,
} from '../helpers';

beforeAll(async () => {
  await loadPhysics();
});

const P = (...xy: number[]) =>
  Array.from({ length: xy.length / 2 }, (_, i) => ({ x: xy[2 * i]!, y: xy[2 * i + 1]! }));

const turned = (degrees: number, x = 0, y = 0): Mat => {
  const a = (degrees * Math.PI) / 180;
  return { a: Math.cos(a), b: Math.sin(a), c: -Math.sin(a), d: Math.cos(a), tx: x, ty: y };
};

const shape = (props: Record<string, PropertyValue>, m: Mat = IDENTITY): ColliderShape =>
  colliderShape(props, m);
const RIGHT = { x: 1, y: 0 };
const DOWN = { x: 0, y: 1 };

describe('where a ray meets a shape (#153)', () => {
  it('meets a box on the face it comes in through, from every side', () => {
    const box = shape({ width: 40, height: 20 });
    expect(rayCast(box, { x: -100, y: 5 }, RIGHT, 1000)).toEqual({ distance: 80, normal: { x: -1, y: 0 } });
    expect(rayCast(box, { x: 3, y: -50 }, DOWN, 1000)).toEqual({ distance: 40, normal: { x: 0, y: -1 } });
    expect(rayCast(box, { x: 100, y: 0 }, { x: -1, y: 0 }, 1000)).toEqual({
      distance: 80,
      normal: { x: 1, y: 0 },
    });
    expect(rayCast(box, { x: 0, y: 60 }, { x: 0, y: -1 }, 1000)).toEqual({
      distance: 50,
      normal: { x: 0, y: 1 },
    });
  });

  it('meets a turned box on its slanted face', () => {
    const box = shape({ width: 40, height: 40 }, turned(45));
    const hit = rayCast(box, { x: -100, y: 0 }, RIGHT, 1000)!;
    // The corner of the diamond points left, at x = −20·√2.
    expect(hit.distance).toBeCloseTo(100 - 20 * Math.SQRT2, 9);
    expect(Math.abs(hit.normal.y)).toBeCloseTo(Math.SQRT1_2, 9);
    expect(hit.normal.x).toBeCloseTo(-Math.SQRT1_2, 9);
  });

  it('meets a circle where it is round, off-centre too', () => {
    const circle = shape({ shape: 'circle', radius: 10 });
    expect(rayCast(circle, { x: -50, y: 0 }, RIGHT, 1000)).toEqual({ distance: 40, normal: { x: -1, y: 0 } });
    const hit = rayCast(circle, { x: -50, y: 6 }, RIGHT, 1000)!;
    expect(hit.distance).toBeCloseTo(50 - 8, 9);
    expect(hit.normal.x).toBeCloseTo(-0.8, 9);
    expect(hit.normal.y).toBeCloseTo(0.6, 9);
  });

  it('meets a capsule on its flat side and on its round end', () => {
    const capsule = shape({ shape: 'capsule', width: 20, height: 60 }); // round ends at y = ±20, radius 10
    expect(rayCast(capsule, { x: -50, y: 0 }, RIGHT, 1000)).toEqual({
      distance: 40,
      normal: { x: -1, y: 0 },
    });
    expect(rayCast(capsule, { x: 0, y: -100 }, DOWN, 1000)).toEqual({
      distance: 70,
      normal: { x: 0, y: -1 },
    });
    const hit = rayCast(capsule, { x: 6, y: -100 }, DOWN, 1000)!;
    expect(hit.distance).toBeCloseTo(100 - 20 - 8, 9);
    expect(hit.normal.x).toBeCloseTo(0.6, 9);
  });

  it('goes down into the notch of a concave polygon and meets its inner floor, not the hull', () => {
    const u = shape({
      shape: 'polygon',
      points: P(-60, -50, -40, -50, -40, 30, 40, 30, 40, -50, 60, -50, 60, 50, -60, 50),
    });
    expect(rayCast(u, { x: 0, y: -100 }, DOWN, 1000)).toEqual({ distance: 130, normal: { x: 0, y: -1 } });
    expect(rayCast(u, { x: -50, y: -100 }, DOWN, 1000)).toEqual({ distance: 50, normal: { x: 0, y: -1 } });
  });

  it('a polygon square answers exactly as the box it stands for, for 900 rays in every direction', () => {
    const box = shape({ width: 40, height: 30 }, turned(20, 5, -3));
    const square = shape(
      { shape: 'polygon', points: P(-20, -15, 20, -15, 20, 15, -20, 15) },
      turned(20, 5, -3),
    );
    let seed = 7;
    const random = () => ((seed = (seed * 16807) % 2147483647) / 2147483647) * 2 - 1;
    let hits = 0;
    for (let i = 0; i < 900; i++) {
      const from = { x: random() * 80, y: random() * 80 };
      const a = random() * Math.PI;
      const dir = { x: Math.cos(a), y: Math.sin(a) };
      const p = rayCast(box, from, dir, 200);
      const q = rayCast(square, from, dir, 200);
      expect(q === null, `ray ${i}`).toBe(p === null);
      if (!p || !q) continue;
      hits++;
      expect(q.distance, `ray ${i}`).toBeCloseTo(p.distance, 9);
      expect(q.normal.x, `ray ${i}`).toBeCloseTo(p.normal.x, 9);
      expect(q.normal.y, `ray ${i}`).toBeCloseTo(p.normal.y, 9);
    }
    expect(hits).toBeGreaterThan(80);
  });

  it('a ray starting inside a shape does not meet it; one on its outline meets it at 0 going in, not going out', () => {
    const box = shape({ width: 40, height: 20 });
    expect(rayCast(box, { x: 0, y: 0 }, RIGHT, 1000)).toBeNull();
    expect(rayCast(shape({ shape: 'circle', radius: 10 }), { x: 2, y: 0 }, RIGHT, 1000)).toBeNull();
    expect(rayCast(box, { x: -20, y: 0 }, RIGHT, 1000)).toEqual({ distance: 0, normal: { x: -1, y: 0 } });
    expect(rayCast(box, { x: -20, y: 0 }, { x: -1, y: 0 }, 1000)).toBeNull();
  });

  it('inside a shape made of parts the ray does not stop at a seam between them', () => {
    // Inside the capsule's straight part but outside its end circle: upwards it would enter the circle.
    const capsule = shape({ shape: 'capsule', width: 20, height: 60 });
    expect(rayCast(capsule, { x: 9, y: -12 }, { x: 0, y: -1 }, 1000)).toBeNull();
    // Along the bottom bar of the U, across the seams of its convex pieces.
    const u = shape({
      shape: 'polygon',
      points: P(-60, -50, -40, -50, -40, 30, 40, 30, 40, -50, 60, -50, 60, 50, -60, 50),
    });
    expect(rayCast(u, { x: -55, y: 40 }, RIGHT, 1000)).toBeNull();
  });

  it('a ray grazing a corner meets it; one passing by or falling short does not', () => {
    const box = shape({ width: 40, height: 20 });
    expect(rayCast(box, { x: -100, y: -10 }, RIGHT, 1000)?.distance).toBeCloseTo(80, 12);
    expect(rayCast(box, { x: -100, y: -10.001 }, RIGHT, 1000)).toBeNull();
    expect(rayCast(box, { x: -100, y: 0 }, RIGHT, 79.9)).toBeNull();
    expect(rayCast(box, { x: -100, y: 0 }, RIGHT, 80)?.distance).toBe(80);
  });
});

/** A scene of objects with one collider each; `add` returns the object and collider ids. */
function scene() {
  const f = makeSpriteScene('Thing');
  const add = (at: Vec2, collider: Record<string, PropertyValue>, parent?: string) => {
    const id = place(f, f.spriteId, at, parent);
    const command = new AddColliderCommand(f.sceneId, id);
    f.stack.execute(command);
    for (const [key, value] of Object.entries(collider))
      f.stack.execute(new SetOverrideCommand(f.sceneId, command.objectId, key, value));
    return { id, collider: command.objectId };
  };
  return { ...f, add };
}

function run(f: SceneFixture, physics: boolean) {
  const started = startWorld(f, { physics, collisions: true, behaviors: true });
  const entity = (id: string) => started.world.findByObjectId(id)!;
  const cast = (
    from: Vec2,
    dir: Vec2,
    length = 1000,
    ignore: string | null = null,
    triggers = false,
    layers = ALL_LAYERS,
  ) =>
    started.collisions.raycast(started.world, from, dir, length, {
      ignore: ignore ? entity(ignore) : null,
      triggers,
      layers,
    });
  const castAll = (
    from: Vec2,
    dir: Vec2,
    length = 1000,
    { ignore = null as string | null, triggers = false, layers = ALL_LAYERS, maxHits = 0 } = {},
  ) =>
    started.collisions.raycastAll(
      started.world,
      from,
      dir,
      length,
      { ignore: ignore ? entity(ignore) : null, triggers, layers },
      maxHits,
    );
  return { ...started, entity, cast, castAll };
}

describe.each(COLLISION_SYSTEMS)('$system: a ray through the world (#153)', ({ physics }) => {
  it('meets the nearest collider, and says which one, where and how far', () => {
    const s = scene();
    const far = s.add({ x: 300, y: 0 }, { width: 20, height: 100 });
    const near = s.add({ x: 100, y: 0 }, { shape: 'circle', radius: 10 });
    const r = run(s, physics);
    expect(r.cast({ x: 0, y: 0 }, RIGHT)).toEqual({
      collider: r.entity(near.collider),
      point: { x: 90, y: 0 },
      normal: { x: -1, y: 0 },
      distance: 90,
    });
    expect(r.cast({ x: 0, y: 30 }, RIGHT)?.collider).toBe(r.entity(far.collider));
    expect(r.cast({ x: 0, y: 30 }, RIGHT, 200)).toBeNull();
  });

  it('passes triggers unless asked, and what it ignores – with everything parented below it', () => {
    const s = scene();
    const trigger = s.add({ x: 50, y: 0 }, { width: 10, height: 100, isTrigger: true });
    const owner = s.add({ x: 100, y: 0 }, { width: 10, height: 100 });
    const child = s.add({ x: 150, y: 0 }, { width: 10, height: 100 }, owner.id);
    const wall = s.add({ x: 300, y: 0 }, { width: 10, height: 100 });
    const r = run(s, physics);
    expect(r.cast({ x: 0, y: 0 }, RIGHT)?.collider).toBe(r.entity(owner.collider));
    expect(r.cast({ x: 0, y: 0 }, RIGHT, 1000, null, true)?.collider).toBe(r.entity(trigger.collider));
    expect(r.cast({ x: 0, y: 0 }, RIGHT, 1000, owner.id)?.collider).toBe(r.entity(wall.collider));
    expect(r.cast({ x: 200, y: 0 }, { x: -1, y: 0 }, 1000, owner.id)).toBeNull();
    expect(r.cast({ x: 120, y: 0 }, RIGHT)?.collider).toBe(r.entity(child.collider));
  });

  it('meets a one-way platform only from the side it blocks from (#155)', () => {
    const s = scene();
    s.add({ x: 0, y: 104 }, { width: 200, height: 8, oneWay: true });
    const r = run(s, physics);
    expect(r.cast({ x: 0, y: 0 }, DOWN)).toMatchObject({ distance: 100, normal: { x: 0, y: -1 } });
    expect(r.cast({ x: 0, y: 200 }, { x: 0, y: -1 })).toBeNull();
    expect(r.cast({ x: -300, y: 104 }, RIGHT)).toBeNull();
  });

  it('meets the cells of a tilemap, the map being the collider', () => {
    const s = scene();
    const wall = new CreateAssetCommand('tile', 'Wall');
    const map = new CreateAssetCommand('tilemap', 'Ground');
    s.stack.execute(wall);
    s.stack.execute(map);
    s.stack.execute(new SetAssetPropertyCommand(wall.asset.id, TILE_SOLID_KEY, true));
    s.stack.execute(new SetAssetPropertyCommand(map.asset.id, TILEMAP_COLUMNS_KEY, 10));
    s.stack.execute(new SetAssetPropertyCommand(map.asset.id, TILEMAP_ROWS_KEY, 10));
    const mapObject = place(s, map.asset.id, { x: 0, y: 0 });
    const layer = (findAsset(s.project, map.asset.id) as TilemapAsset).layers[0]!.id;
    // Cells of 48, centred: the bottom row's top face is at 4·48 = 192, a pillar in column 7 from row 5.
    const cells = [
      ...Array.from({ length: 10 }, (_, x) => ({ x, y: 9, tileId: wall.asset.id })),
      ...[5, 6, 7, 8].map((y) => ({ x: 7, y, tileId: wall.asset.id })),
    ];
    s.stack.execute(new PaintTilesCommand(map.asset.id, layer, cells));
    const r = run(s, physics);
    expect(r.cast({ x: 0, y: 0 }, DOWN)).toEqual({
      collider: r.entity(mapObject),
      point: { x: 0, y: 192 },
      normal: { x: 0, y: -1 },
      distance: 192,
    });
    expect(r.cast({ x: 0, y: 100 }, RIGHT)).toMatchObject({
      point: { x: 96, y: 100 },
      normal: { x: -1, y: 0 },
    });
  });

  it('passes what sits on a layer it does not look at, and meets the next one behind it (#158)', () => {
    const s = scene();
    // Near sits on layer 1, far on layer 0; the near one also collides with nothing at all, which
    // is a collider's own business and must not decide what a ray may see.
    s.add({ x: 100, y: 0 }, { width: 20, height: 100, [COLLISION_LAYER_KEY]: 1, [COLLIDES_WITH_KEY]: 0 });
    const far = s.add({ x: 300, y: 0 }, { width: 20, height: 100 });
    const r = run(s, physics);
    expect(r.cast({ x: 0, y: 0 }, RIGHT)?.distance).toBe(90);
    expect(r.cast({ x: 0, y: 0 }, RIGHT, 1000, null, false, maskWith(ALL_LAYERS, 1, false))).toMatchObject({
      collider: r.entity(far.collider),
      distance: 290,
    });
    expect(r.cast({ x: 0, y: 0 }, RIGHT, 1000, null, false, 0)).toBeNull();
  });

  it('a tilemap is met or passed by its own layer, like any collider (#158)', () => {
    const s = scene();
    const wall = new CreateAssetCommand('tile', 'Wall');
    const map = new CreateAssetCommand('tilemap', 'Ground');
    s.stack.execute(wall);
    s.stack.execute(map);
    s.stack.execute(new SetAssetPropertyCommand(wall.asset.id, TILE_SOLID_KEY, true));
    s.stack.execute(new SetAssetPropertyCommand(map.asset.id, TILEMAP_COLUMNS_KEY, 10));
    s.stack.execute(new SetAssetPropertyCommand(map.asset.id, TILEMAP_ROWS_KEY, 10));
    const mapObject = place(s, map.asset.id, { x: 0, y: 0 });
    s.stack.execute(new SetOverrideCommand(s.sceneId, mapObject, COLLISION_LAYER_KEY, 2));
    const layer = (findAsset(s.project, map.asset.id) as TilemapAsset).layers[0]!.id;
    s.stack.execute(
      new PaintTilesCommand(
        map.asset.id,
        layer,
        Array.from({ length: 10 }, (_, x) => ({ x, y: 9, tileId: wall.asset.id })),
      ),
    );
    const r = run(s, physics);
    const down = (layers: number) => r.cast({ x: 0, y: 0 }, DOWN, 1000, null, false, layers);
    expect(down(ALL_LAYERS)?.distance).toBe(192);
    expect(down(1 << 2)?.collider).toBe(r.entity(mapObject));
    expect(down(maskWith(ALL_LAYERS, 2, false))).toBeNull();
  });

  it('the Raycast node casts from the graph, skips its owner and hands on what it met', () => {
    const s = scene();
    const hero = s.add({ x: 0, y: 0 }, { width: 20, height: 20 });
    s.add({ x: 0, y: 150 }, { width: 200, height: 20 }); // top face at 140
    const behavior = makeBehavior(s, 'Eyes');
    place(s, behavior.id, { x: 0, y: 0 }, hero.id);
    const edit = graphEditor(s, behavior);
    const update = edit.addNode('OnUpdate');
    const ray = edit.addNode('Raycast', { fromX: 0, fromY: 0, dirX: 0, dirY: 1, length: 500 });
    const logHit = edit.addNode('Log');
    const logDistance = edit.addNode('Log');
    edit.wire([
      [update, 'exec', ray, 'exec'],
      [ray, 'exec', logHit, 'exec'],
      [ray, 'hit', logHit, 'message'],
      [logHit, 'exec', logDistance, 'exec'],
      [ray, 'distance', logDistance, 'message'],
    ]);
    const r = run(s, physics);
    r.frame(1 / 60);
    // It starts inside its own hero, which it would not meet anyway; the floor is 140 down.
    expect(r.world.log).toEqual(['true', '140']);
    expect(r.world.rays).toEqual([{ from: { x: 0, y: 0 }, to: { x: 0, y: 140 }, hit: true, time: 1 / 60 }]);
  });

  it('the node looks only at the layers its setting names, and at every one without it (#158)', () => {
    const cast = (layers?: number) => {
      const s = scene();
      const hero = s.add({ x: 0, y: 0 }, { width: 20, height: 20 });
      s.add({ x: 0, y: 150 }, { width: 200, height: 20, [COLLISION_LAYER_KEY]: 1 }); // top face at 140
      s.add({ x: 0, y: 300 }, { width: 200, height: 20 }); // top face at 290, layer 0
      const behavior = makeBehavior(s, 'Eyes');
      place(s, behavior.id, { x: 0, y: 0 }, hero.id);
      const edit = graphEditor(s, behavior);
      const update = edit.addNode('OnUpdate');
      const params: Record<string, PropertyValue> = { fromX: 0, fromY: 0, dirX: 0, dirY: 1, length: 500 };
      if (layers !== undefined) params[RAY_LAYERS_PARAM] = layers;
      const ray = edit.addNode('Raycast', params);
      const log = edit.addNode('Log');
      edit.wire([
        [update, 'exec', ray, 'exec'],
        [ray, 'exec', log, 'exec'],
        [ray, 'distance', log, 'message'],
      ]);
      const r = run(s, physics);
      r.frame(1 / 60);
      return r.world.log;
    };
    // A graph from before the setting existed carries no `layers` at all and must answer as it did.
    expect(cast()).toEqual(['140']);
    expect(cast(ALL_LAYERS)).toEqual(['140']);
    expect(cast(maskWith(ALL_LAYERS, 1, false))).toEqual(['290']);
    expect(cast(0)).toEqual(['0']);
  });
});

describe.each(COLLISION_SYSTEMS)('$system: every hit on the line (#157)', ({ physics }) => {
  it('gives them nearest first, and the nearest of them is what a plain raycast says', () => {
    const s = scene();
    const far = s.add({ x: 300, y: 0 }, { width: 20, height: 100 }); // near face at 290
    const near = s.add({ x: 100, y: 0 }, { shape: 'circle', radius: 10 }); // near face at 90
    const middle = s.add({ x: 200, y: 0 }, { width: 20, height: 100 }); // near face at 190
    const r = run(s, physics);
    const hits = r.castAll({ x: 0, y: 0 }, RIGHT);
    expect(hits.map((hit) => hit.distance)).toEqual([90, 190, 290]);
    expect(hits.map((hit) => hit.collider)).toEqual([
      r.entity(near.collider),
      r.entity(middle.collider),
      r.entity(far.collider),
    ]);
    expect(hits[0]).toEqual(r.cast({ x: 0, y: 0 }, RIGHT));
    // Every hit is where it says it is, with the face's normal pointing back at the ray.
    expect(hits[1]).toMatchObject({ point: { x: 190, y: 0 }, normal: { x: -1, y: 0 } });
    expect(r.castAll({ x: 0, y: 0 }, RIGHT, 200).map((hit) => hit.distance)).toEqual([90, 190]);
    expect(r.castAll({ x: 0, y: -300 }, RIGHT)).toEqual([]);
  });

  it('counts a collider once however many convex pieces it is made of', () => {
    const s = scene();
    // A U on its side: the ray down the middle enters the left arm, the notch and the right arm.
    const u = s.add(
      { x: 0, y: 0 },
      { shape: 'polygon', points: P(-60, -50, -40, -50, -40, 30, 40, 30, 40, -50, 60, -50, 60, 50, -60, 50) },
    );
    const r = run(s, physics);
    const hits = r.castAll({ x: 0, y: -100 }, DOWN);
    expect(hits).toHaveLength(1);
    expect(hits[0]).toMatchObject({ collider: r.entity(u.collider), distance: 130 });
  });

  it('keeps the filters of a plain cast: the owner, triggers and the layers (#158)', () => {
    const s = scene();
    const owner = s.add({ x: 100, y: 0 }, { width: 10, height: 100 });
    const trigger = s.add({ x: 150, y: 0 }, { width: 10, height: 100, isTrigger: true });
    const hidden = s.add({ x: 200, y: 0 }, { width: 10, height: 100, [COLLISION_LAYER_KEY]: 1 });
    const wall = s.add({ x: 300, y: 0 }, { width: 10, height: 100 });
    const r = run(s, physics);
    const ids = (hits: { collider: unknown }[]) => hits.map((hit) => hit.collider);
    expect(ids(r.castAll({ x: 0, y: 0 }, RIGHT))).toEqual([
      r.entity(owner.collider),
      r.entity(hidden.collider),
      r.entity(wall.collider),
    ]);
    expect(ids(r.castAll({ x: 0, y: 0 }, RIGHT, 1000, { triggers: true }))).toContain(
      r.entity(trigger.collider),
    );
    expect(ids(r.castAll({ x: 0, y: 0 }, RIGHT, 1000, { ignore: owner.id }))).toEqual([
      r.entity(hidden.collider),
      r.entity(wall.collider),
    ]);
    expect(ids(r.castAll({ x: 0, y: 0 }, RIGHT, 1000, { layers: maskWith(ALL_LAYERS, 1, false) }))).toEqual([
      r.entity(owner.collider),
      r.entity(wall.collider),
    ]);
  });

  it('meets a tilemap once per cell the ray goes through, the map being the collider each time', () => {
    const s = scene();
    const wall = new CreateAssetCommand('tile', 'Wall');
    const map = new CreateAssetCommand('tilemap', 'Ground');
    s.stack.execute(wall);
    s.stack.execute(map);
    s.stack.execute(new SetAssetPropertyCommand(wall.asset.id, TILE_SOLID_KEY, true));
    s.stack.execute(new SetAssetPropertyCommand(map.asset.id, TILEMAP_COLUMNS_KEY, 10));
    s.stack.execute(new SetAssetPropertyCommand(map.asset.id, TILEMAP_ROWS_KEY, 10));
    const mapObject = place(s, map.asset.id, { x: 0, y: 0 });
    const layer = (findAsset(s.project, map.asset.id) as TilemapAsset).layers[0]!.id;
    // Cells of 48, centred: a lone cell in row 5 (top face at 0) and one in row 9 (top face at 192).
    s.stack.execute(
      new PaintTilesCommand(map.asset.id, layer, [
        { x: 5, y: 5, tileId: wall.asset.id },
        { x: 5, y: 9, tileId: wall.asset.id },
      ]),
    );
    const r = run(s, physics);
    const hits = r.castAll({ x: 0, y: -100 }, DOWN);
    expect(hits.map((hit) => hit.distance)).toEqual([100, 292]);
    expect(hits.map((hit) => hit.collider)).toEqual([r.entity(mapObject), r.entity(mapObject)]);
  });

  it('"max hits" keeps that many of the nearest, and 0 keeps them all', () => {
    const s = scene();
    s.add({ x: 100, y: 0 }, { width: 20, height: 100 });
    s.add({ x: 200, y: 0 }, { width: 20, height: 100 });
    s.add({ x: 300, y: 0 }, { width: 20, height: 100 });
    const r = run(s, physics);
    const far = (maxHits: number) =>
      r.castAll({ x: 0, y: 0 }, RIGHT, 1000, { maxHits }).map((h) => h.distance);
    expect(far(0)).toEqual([90, 190, 290]);
    expect(far(2)).toEqual([90, 190]);
    expect(far(9)).toEqual([90, 190, 290]);
  });

  it('the node hands the hits to the graph as lists, and the objects in them are objects', () => {
    const s = scene();
    const hero = s.add({ x: 0, y: 0 }, { width: 20, height: 20 });
    s.add({ x: 0, y: 150 }, { width: 200, height: 20 }); // top face at 140
    s.add({ x: 0, y: 300 }, { width: 200, height: 20 }); // top face at 290
    const behavior = makeBehavior(s, 'Eyes');
    place(s, behavior.id, { x: 0, y: 0 }, hero.id);
    const edit = graphEditor(s, behavior);
    const update = edit.addNode('OnUpdate');
    const ray = edit.addNode('RaycastAll', { fromX: 0, fromY: 0, dirX: 0, dirY: 1, length: 500 });
    const logCount = edit.addNode('Log');
    const logDistances = edit.addNode('Log');
    const second = edit.addNode('ItemAt', { index: 1 });
    const where = edit.addNode('GetPosition');
    const logSecond = edit.addNode('Log');
    edit.wire([
      [update, 'exec', ray, 'exec'],
      [ray, 'exec', logCount, 'exec'],
      [ray, 'count', logCount, 'message'],
      [logCount, 'exec', logDistances, 'exec'],
      [ray, 'distances', logDistances, 'message'],
      [ray, 'objects', second, 'list'],
      [second, 'item', where, 'object'],
      [logDistances, 'exec', logSecond, 'exec'],
      [where, 'worldY', logSecond, 'message'],
    ]);
    const r = run(s, physics);
    r.frame(1 / 60);
    // It starts inside its own hero, which "Ignore owner" leaves out anyway. The last line is the
    // proof that the list holds live objects and not their names: a name has no position (#157).
    expect(r.world.log).toEqual(['2', '140, 290', '300']);
    // The ray is drawn to the last thing it met, which is how far it looked.
    expect(r.world.rays).toEqual([{ from: { x: 0, y: 0 }, to: { x: 0, y: 290 }, hit: true, time: 1 / 60 }]);
  });
});

describe('the rays a run remembers for drawing (#153)', () => {
  it('keeps those of the last moment only, and a ray that met nothing ends at its length', () => {
    const s = scene();
    const r = run(s, false);
    r.world.noteRay({ x: 0, y: 0 }, { x: 10, y: 0 }, false);
    r.frame(RAY_SHOWN / 2);
    r.world.noteRay({ x: 0, y: 0 }, { x: 20, y: 0 }, true);
    r.frame(RAY_SHOWN);
    r.world.noteRay({ x: 0, y: 0 }, { x: 30, y: 0 }, false);
    expect(r.world.rays.map((ray) => ray.to.x)).toEqual([20, 30]);
  });
});