math bench

.gitignore

@@ -23,3 +23,6 @@ dist-ssr
 *.njsproj
 *.sln
 *.sw?
+
+# Packed devtools
+devtools.zip

deno.json

@@ -3,7 +3,8 @@
     "dev": "deno run -A --node-modules-dir npm:vite",
     "build": "deno run -A --node-modules-dir npm:vite build",
     "preview": "deno run -A --node-modules-dir npm:vite preview",
-    "serve": "deno run --allow-net --allow-read jsr:@std/http@1/file-server dist/"
+    "serve": "deno run --allow-net --allow-read jsr:@std/http@1/file-server dist/",
+    "pack-devtools": "rm -rf devtools.zip && deno run -A npm:web-ext build -o --source-dir devtools --artifacts-dir devtools.zip"
   },
   "compilerOptions": {
     "lib": [
@@ -13,7 +14,7 @@
     ]
   },
   "imports": {
-    "@bearmetal/doodler": "jsr:@bearmetal/doodler@0.0.5-b",
+    "@bearmetal/doodler": "jsr:@bearmetal/doodler@0.0.5-c",
     "@deno/vite-plugin": "npm:@deno/vite-plugin@^1.0.4",
     "vite": "npm:vite@^6.0.1"
   }

devtools/manifest.json

@@ -1,8 +1,9 @@
 {
   "manifest_version": 2,
-  "name": "Context Stack DevTools",
+  "name": "SNR DevTools",
   "version": "1.0",
   "description": "A devtools panel to view and edit context stack values.",
+  "author": "Emmaline Autumn",
   "devtools_page": "devtools.html",
   "background": {
     "scripts": [
@@ -24,5 +25,13 @@
     "devtools",
     "tabs",
     "*://*/*"
-  ]
+  ],
+  "icons": {
+    "48": "train icon.png"
+  },
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "snrdt@cyborggrizzly.com"
+    }
+  }
 }

src/lib/resources.ts

@@ -1,16 +1,54 @@
+// namespace:type/location
+type sprite = "sprite";
+type img = "img";
+type audio = "audio";
+type ResourceType = keyof ResourceMap;
+type SpriteId = `${string}:${sprite}/${string}`;
+
+interface ResourceMap {
+  sprite: HTMLImageElement;
+  img: HTMLImageElement;
+  audio: HTMLAudioElement;
+}
+type NamespacedId<T extends keyof ResourceMap> = `${string}:${T}/${string}`;
+
+/**
+ * Resources are stored in namespaces, and can be accessed by their namespaced id.
+ * Sprites are located in blob storage as a single png file.
+ * Audio is located in blob storage as a single mp3 file.
+ *
+ * Custom resources can be loaded via the public API, however they will not be loaded on other clients.
+ * Ideally, engine and car definitions should be stored in the resource manager so that custom cars can be created.
+ */
 export class ResourceManager {
   private resources: Map<string, unknown> = new Map();
   private statuses: Map<string, Promise<boolean>> = new Map();
 
-  get<T>(name: string): T {
+  get<K extends ResourceType>(name: NamespacedId<K>): ResourceMap[K];
+  get<T>(name: string): T;
+  get<T>(
+    name: string,
+  ): T {
     if (!this.resources.has(name)) {
       throw new Error(`Resource ${name} not found`);
     }
     return this.resources.get(name) as T;
   }
 
-  set(name: string, value: unknown) {
+  set<T extends keyof ResourceMap>(
+    name: NamespacedId<T>,
+    value: unknown,
+  ) {
+    const identifier = parseNamespacedId(name);
     if (typeof (value as EventSource).addEventListener === "function") {
+      if (value instanceof Image) {
+        // During development, we can use the local file system
+        value.src =
+          `/blobs/${identifier.namespace}/${identifier.type}/${identifier.name}${
+            extensionByType(identifier.type)
+          }`;
+        console.log(value.src);
+      }
       this.statuses.set(
         name,
         new Promise((resolve) => {
@@ -36,3 +74,28 @@ export class ResourceManager {
     return Promise.all(Array.from(this.statuses.values()));
   }
 }
+
+function extensionByType(type: ResourceType) {
+  switch (type) {
+    case "img":
+      return ".png";
+    case "audio":
+      return ".mp3";
+    case "sprite":
+      return ".png";
+  }
+}
+
+type NamespaceIdentifier<T extends ResourceType> = {
+  namespace: string;
+  type: T;
+  name: string;
+};
+
+function parseNamespacedId<T extends ResourceType>(
+  id: NamespacedId<T>,
+): NamespaceIdentifier<T> {
+  const [namespace, location] = id.split(":");
+  const [type, ...name] = location.split("/");
+  return { namespace, type: type as T, name: name.join("/") };
+}

src/main.ts

@@ -20,9 +20,12 @@ const resources = new ResourceManager();
 const doodler = new ZoomableDoodler({
   fillScreen: true,
   bg: "#302040",
-});
+  noSmooth: true,
-(doodler as any as { ctx: CanvasRenderingContext2D }).ctx
+}, () => {});
+setTimeout(() => {
+  (doodler as any as { ctx: CanvasRenderingContext2D }).ctx
     .imageSmoothingEnabled = false;
+}, 0);
 // doodler.minScale = 0.1;
 (doodler as any).scale = 3.14;
 
@@ -37,13 +40,18 @@ const colors = [
   "violet",
 ];
 
-const _debug: Debug = JSON.parse(localStorage.getItem("debug") || "0") || {
+const _fullDebug: Debug = {
   track: false,
   train: false,
   path: false,
   car: false,
+  bogies: false,
+  angles: false,
 };
 
+const storedDebug = JSON.parse(localStorage.getItem("debug") || "0");
+const _debug: Debug = Object.assign({}, _fullDebug, storedDebug);
+
 const debug = new Proxy(_debug, {
   get: (_, prop: string) => {
     // if (prop !in _debug) {
@@ -107,3 +115,8 @@ gameLoop.start(state);
 if (import.meta.env.DEV) {
   console.log("Running in development mode");
 }
+
+globalThis.TWO_PI = Math.PI * 2;
+declare global {
+  var TWO_PI: number;
+}

src/math/lerp.ts

@@ -9,3 +9,19 @@ export const map = (
   x2: number,
   y2: number,
 ) => (value - x1) * (y2 - x2) / (y1 - x1) + x2;
+
+export function lerpAngle(a: number, b: number, t: number) {
+  let diff = b - a;
+  // Wrap difference to [-PI, PI]
+  while (diff < -Math.PI) diff += 2 * Math.PI;
+  while (diff > Math.PI) diff -= 2 * Math.PI;
+  return a + diff * t;
+}
+
+export function averageAngles(angle1: number, angle2: number) {
+  // Convert angles to unit vectors
+  const x = Math.cos(angle1) + Math.cos(angle2);
+  const y = Math.sin(angle1) + Math.sin(angle2);
+  // Compute the angle of the resulting vector
+  return Math.atan2(y, x);
+}

src/state/states/LoadState.ts

@@ -34,9 +34,11 @@ export class LoadState extends State<States> {
 
     bootstrapInputs();
 
-    resources.set("engine-sprites", new Image());
+    // This should be driven by a manifest
-    resources.get<HTMLImageElement>("engine-sprites")!.src =
+    resources.set("snr:sprite/engine", new Image());
-      "/sprites/EngineSprites.png";
+    resources.set("snr:sprite/LargeLady", new Image());
+    // resources.get<HTMLImageElement>("snr:sprite/engine")!.src =
+    //   "/sprites/EngineSprites.png";
     resources.ready().then(() => {
       this.stateMachine.transitionTo(States.RUNNING);
     });

src/state/states/RunningState.ts

@@ -8,6 +8,7 @@ import { DotFollower } from "../../train/newTrain.ts";
 import { Train } from "../../train/train.ts";
 import { State } from "../machine.ts";
 import { States } from "./index.ts";
+import { LargeLady, LargeLadyTender } from "../../train/LargeLady.ts";
 
 export class RunningState extends State<States> {
   override name: States = States.RUNNING;
@@ -58,12 +59,17 @@ export class RunningState extends State<States> {
       // const path = track.path;
       // const follower = new DotFollower(path, path.points[0].copy());
       // ctx.trains.push(follower);
-      const train = new Train(track.path, [new RedEngine(), new Tender()]);
+      // const train = new Train(track.path, [new LargeLady(), new Tender()]);
-      ctx.trains.push(train);
+      // ctx.trains.push(train);
     });
+    const train = new Train(track.path, [
+      new LargeLady(),
+      new LargeLadyTender(),
+    ]);
+    ctx.trains.push(train);
     // const trainCount = 1000;
     // for (let i = 0; i < trainCount; i++) {
-    //   const train = new Train(track.path, [new RedEngine(), new Tender()]);
+    //   const train = new Train(track.path, [new LargeLady(), new Tender()]);
     //   ctx.trains.push(train);
     // }
 

src/test/angleMathBench.test.ts

@@ -0,0 +1,32 @@
+/// <reference no-default-lib="true" />
+/// <reference lib="esnext" />
+/// <reference lib="dom" />
+/// <reference lib="dom.iterable" />
+/// <reference lib="dom.asynciterable" />
+/// <reference lib="deno.ns" />
+
+import { averageAngles, lerpAngle } from "../math/lerp.ts";
+import { testPerformance } from "./bench.ts";
+
+Deno.test("angle math", () => {
+  console.log("Average angles");
+  testPerformance(
+    () => {
+      const a = Math.random() * Math.PI * 2;
+      const b = Math.random() * Math.PI * 2;
+      const avg = averageAngles(a, b);
+    },
+    10000,
+    60,
+  );
+  console.log("Lerp angles");
+  testPerformance(
+    () => {
+      const a = Math.random() * Math.PI * 2;
+      const b = Math.random() * Math.PI * 2;
+      const avg = lerpAngle(a, b, .5);
+    },
+    10000,
+    60,
+  );
+});

src/track/shapes.ts

@@ -44,7 +44,7 @@ export class BankLeft extends TrackSegment {
     const p2 = start.copy();
     const p3 = start.copy();
     const p4 = start.copy();
-    const scale = 33;
+    const scale = 66;
 
     p2.add(new Vector(1, 0).mult(scale));
     p3.set(p2);
@@ -70,7 +70,7 @@ export class BankRight extends TrackSegment {
     const p2 = start.copy();
     const p3 = start.copy();
     const p4 = start.copy();
-    const scale = 33;
+    const scale = 66;
 
     p2.add(new Vector(1, 0).mult(scale));
     p3.set(p2);

src/track/system.ts

@@ -499,7 +499,14 @@ export class Spline<T extends PathSegment = PathSegment> {
   ctx?: CanvasRenderingContext2D;
 
   evenPoints: PathPoint[];
-  pointSpacing: number;
+  _pointSpacing: number;
+  get pointSpacing() {
+    return this._pointSpacing;
+  }
+  set pointSpacing(value: number) {
+    this._pointSpacing = value;
+    this.evenPoints = this.calculateEvenlySpacedPoints(value);
+  }
 
   get points() {
     return Array.from(new Set(this.segments.flatMap((s) => s.points)));
@@ -514,8 +521,8 @@ export class Spline<T extends PathSegment = PathSegment> {
     if (this.segments.at(-1)?.next === this.segments[0]) {
       this.looped = true;
     }
-    this.pointSpacing = 1;
+    this._pointSpacing = 1;
-    this.evenPoints = this.calculateEvenlySpacedPoints(1);
+    this.evenPoints = this.calculateEvenlySpacedPoints(this._pointSpacing);
     this.nodes = [];
     // for (let i = 0; i < this.points.length; i += 3) {
     //   const node: IControlNode = {
@@ -549,7 +556,7 @@ export class Spline<T extends PathSegment = PathSegment> {
   }
 
   calculateEvenlySpacedPoints(spacing: number, resolution = 1): PathPoint[] {
-    this.pointSpacing = 1;
+    // this._pointSpacing = 1;
     // return this.segments.flatMap(s => s.calculateEvenlySpacedPoints(spacing, resolution));
     const points: PathPoint[] = [];
 
@@ -589,7 +596,7 @@ export class Spline<T extends PathSegment = PathSegment> {
       }
     }
 
-    this.evenPoints = points;
+    // this.evenPoints = points;
 
     return points;
   }

src/train/LargeLady.ts

@@ -0,0 +1,188 @@
+import { Doodler, Vector } from "@bearmetal/doodler";
+import { Train, TrainCar } from "./train.ts";
+import { getContextItem } from "../lib/context.ts";
+import { ResourceManager } from "../lib/resources.ts";
+import { debug } from "node:console";
+import { averageAngles } from "../math/lerp.ts";
+
+export class LargeLady extends TrainCar {
+  scale = 1;
+  constructor() {
+    const resources = getContextItem<ResourceManager>("resources");
+    const img = resources.get<HTMLImageElement>("snr:sprite/LargeLady")!;
+    super(50, 10, img, 132, 23, {
+      at: new Vector(0, 0),
+      width: 132,
+      height: 23,
+    });
+
+    this.bogies = [
+      {
+        pos: new Vector(0, 0),
+        angle: 0,
+        length: 35 * this.scale,
+        sprite: {
+          at: new Vector(0, 24),
+          width: 35,
+          height: 23,
+          offset: new Vector(-23, -11.5),
+        },
+      },
+      {
+        pos: new Vector(0, 0),
+        angle: 0,
+        length: 64 * this.scale,
+        // sprite: {
+        //   at: new Vector(0, 23),
+        //   width: 33,
+        //   height: 19,
+        //   offset: new Vector(-19, -9.5),
+        // },
+        sprite: {
+          at: new Vector(36, 24),
+          width: 60,
+          height: 23,
+          offset: new Vector(-35, -11.5),
+        },
+      },
+      {
+        pos: new Vector(0, 0),
+        angle: 0,
+        length: 35 * this.scale,
+        sprite: {
+          at: new Vector(36, 24),
+          width: 60,
+          height: 23,
+          offset: new Vector(-35, -11.5),
+        },
+      },
+      {
+        pos: new Vector(0, 0),
+        angle: 0,
+        length: 28,
+        sprite: {
+          at: new Vector(97, 24),
+          width: 22,
+          height: 23,
+          offset: new Vector(-11, -11.5),
+        },
+      },
+    ];
+  }
+
+  override draw(): void {
+    const doodler = getContextItem<Doodler>("doodler");
+    for (const b of this.bogies) {
+      if (!b.sprite) continue;
+      doodler.drawRotated(b.pos, b.angle + (b.rotate ? 0 : Math.PI), () => {
+        doodler.drawSprite(
+          this.img,
+          b.sprite!.at,
+          b.sprite!.width,
+          b.sprite!.height,
+          b.pos.copy().add(b.sprite!.offset ?? new Vector(0, 0)),
+          b.sprite!.width,
+          b.sprite!.height,
+        );
+      });
+    }
+
+    const b = this.bogies[2];
+    const a = this.bogies[1];
+    // const origin = Vector.add(Vector.sub(a.pos, b.pos).div(2), b.pos);
+    // const angle = Vector.sub(b.pos, a.pos).heading();
+    const debug = getContextItem<Debug>("debug");
+    if (debug.bogies) return;
+
+    const difAngle = Vector.sub(a.pos, b.pos).heading();
+    const origin = b.pos.copy().add(new Vector(33, 0).rotate(difAngle));
+    const angle = b.angle;
+    const avgAngle = averageAngles(difAngle, angle) + Math.PI;
+
+    doodler.drawRotated(origin, avgAngle, () => {
+      this.sprite
+        ? doodler.drawSprite(
+          this.img,
+          this.sprite.at,
+          this.sprite.width,
+          this.sprite.height,
+          origin.copy().sub(
+            this.imgWidth * this.scale / 2,
+            this.imgHeight * this.scale / 2,
+          ),
+          this.imgWidth * this.scale,
+          this.imgHeight * this.scale,
+        )
+        : doodler.drawImage(
+          this.img,
+          origin.copy().sub(this.imgWidth / 2, this.imgHeight / 2),
+        );
+    });
+    // doodler.drawCircle(origin, 4, { color: "blue" });
+
+    doodler.deferDrawing(() => {
+      doodler.drawRotated(origin, avgAngle + Math.PI, () => {
+        doodler.drawSprite(
+          this.img,
+          new Vector(133, 0),
+          28,
+          23,
+          origin.copy().sub(93, this.imgHeight / 2),
+          28,
+          23,
+        );
+      });
+    });
+  }
+}
+
+export class LargeLadyTender extends TrainCar {
+  constructor() {
+    const resources = getContextItem<ResourceManager>("resources");
+    const sprite = resources.get("snr:sprite/LargeLady");
+    super(40, 39, sprite, 98, 23, {
+      at: new Vector(0, 48),
+      width: 98,
+      height: 23,
+    });
+
+    this.leading = 10;
+  }
+
+  override draw(): void {
+    const doodler = getContextItem<Doodler>("doodler");
+    const b = this.bogies[0];
+    doodler.drawRotated(b.pos, b.angle, () => {
+      doodler.drawSprite(
+        this.img,
+        new Vector(97, 24),
+        22,
+        23,
+        b.pos.copy().sub(11, 11.5),
+        22,
+        23,
+      );
+    });
+
+    const angle = Vector.sub(this.bogies[1].pos, this.bogies[0].pos).heading();
+    const origin = this.bogies[1].pos.copy().add(
+      new Vector(-11, 0).rotate(angle),
+    );
+    doodler.drawRotated(origin, angle, () => {
+      this.sprite
+        ? doodler.drawSprite(
+          this.img,
+          this.sprite.at,
+          this.sprite.width,
+          this.sprite.height,
+          origin.copy().sub(this.imgWidth / 2, this.imgHeight / 2),
+          this.imgWidth,
+          this.imgHeight,
+        )
+        : doodler.drawImage(
+          this.img,
+          origin.copy().sub(this.imgWidth / 2, this.imgHeight / 2),
+        );
+    });
+  }
+}

src/train/cars.ts

@@ -6,50 +6,85 @@ import { getContextItem } from "../lib/context.ts";
 export class Tender extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(25, resources.get<HTMLImageElement>("engine-sprites")!, 40, 20, {
+    super(
+      25,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      40,
+      20,
+      {
         at: new Vector(80, 0),
         width: 40,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class Tank extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(50, resources.get<HTMLImageElement>("engine-sprites")!, 70, 20, {
+    super(
+      50,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      70,
+      20,
+      {
         at: new Vector(80, 20),
         width: 70,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class YellowDumpCar extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(50, resources.get<HTMLImageElement>("engine-sprites")!, 70, 20, {
+    super(
+      50,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      70,
+      20,
+      {
         at: new Vector(80, 40),
         width: 70,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class GrayDumpCar extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(50, resources.get<HTMLImageElement>("engine-sprites")!, 70, 20, {
+    super(
+      50,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      70,
+      20,
+      {
         at: new Vector(80, 60),
         width: 70,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class NullCar extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(50, resources.get<HTMLImageElement>("engine-sprites")!, 70, 20, {
+    super(
+      50,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      70,
+      20,
+      {
         at: new Vector(80, 80),
         width: 70,
         height: 20,
-    });
+      },
+    );
   }
 }

src/train/engines.ts

@@ -6,50 +6,85 @@ import { ResourceManager } from "../lib/resources.ts";
 export class RedEngine extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(55, resources.get<HTMLImageElement>("engine-sprites")!, 80, 20, {
+    super(
+      55,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      80,
+      20,
+      {
         at: new Vector(0, 60),
         width: 80,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class PurpleEngine extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(55, resources.get<HTMLImageElement>("engine-sprites")!, 80, 20, {
+    super(
+      55,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      80,
+      20,
+      {
         at: new Vector(0, 60),
         width: 80,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class GreenEngine extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(55, resources.get<HTMLImageElement>("engine-sprites")!, 80, 20, {
+    super(
+      55,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      80,
+      20,
+      {
         at: new Vector(0, 40),
         width: 80,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class GrayEngine extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(55, resources.get<HTMLImageElement>("engine-sprites")!, 80, 20, {
+    super(
+      55,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      80,
+      20,
+      {
         at: new Vector(0, 20),
         width: 80,
         height: 20,
-    });
+      },
+    );
   }
 }
 export class BlueEngine extends TrainCar {
   constructor() {
     const resources = getContextItem<ResourceManager>("resources");
-    super(55, resources.get<HTMLImageElement>("engine-sprites")!, 80, 20, {
+    super(
+      55,
+      10,
+      resources.get<HTMLImageElement>("snr:sprite/engine")!,
+      80,
+      20,
+      {
         at: new Vector(0, 0),
         width: 80,
         height: 20,
-    });
+      },
+    );
   }
 }

src/train/train.ts

@@ -2,7 +2,7 @@ import { getContextItem } from "../lib/context.ts";
 import { Doodler, Vector } from "@bearmetal/doodler";
 import { Spline, TrackSegment, TrackSystem } from "../track/system.ts";
 import { Debuggable } from "../lib/debuggable.ts";
-import { map } from "../math/lerp.ts";
+import { lerp, lerpAngle, map } from "../math/lerp.ts";
 
 export class Train extends Debuggable {
   nodes: Vector[] = [];
@@ -12,62 +12,68 @@ export class Train extends Debuggable {
   path: Spline<TrackSegment>;
   t: number;
 
-  spacing = 20;
+  spacing = 5;
 
-  speed = 10;
+  speed = 0;
 
   get segments() {
-    return Array.from(new Set(this.cars.flatMap((c) => c.segments)));
+    return Array.from(
+      new Set(this.cars.flatMap((c) => c.segments.values().toArray())),
+    );
   }
 
-  constructor(track: Spline<TrackSegment>, cars: TrainCar[]) {
+  constructor(track: Spline<TrackSegment>, cars: TrainCar[], t = 0) {
     super("train", "path");
     this.path = track;
-    this.t = 0;
+    this.path.pointSpacing = 5;
     this.cars = cars;
+    this.t = this.cars.reduce((acc, c) => acc + c.length, 0) +
+      (this.cars.length - 1) * this.spacing;
+    this.t = this.t / this.path.pointSpacing;
 
     let currentOffset = 0;
-    try {
+    // try {
     for (const car of this.cars) {
-        currentOffset += this.spacing;
+      car.train = this;
-        const a = this.path.followEvenPoints(this.t - currentOffset);
+      currentOffset += car.moveAlongPath(this.t - currentOffset, true) +
-        currentOffset += car.length;
+        this.spacing / this.path.pointSpacing;
-        const b = this.path.followEvenPoints(this.t - currentOffset);
-        car.points = [a.p, b.p];
-        this.nodes.push(a.p, b.p);
-        car.segments = [a.segmentId, b.segmentId];
-      }
-    } catch {
-      currentOffset = 0;
-      for (const car of this.cars.toReversed()) {
-        currentOffset += this.spacing;
-        const a = this.path.followEvenPoints(this.t - currentOffset);
-        currentOffset += car.length;
-        const b = this.path.followEvenPoints(this.t - currentOffset);
-        car.points = [a.p, b.p];
-        this.nodes.push(a.p, b.p);
-        car.segments = [a.segmentId, b.segmentId];
-      }
     }
+    // } catch {
+    //   currentOffset = 0;
+    //   console.log("Reversed");
+    //   for (const car of this.cars.toReversed()) {
+    //     for (const [i, bogie] of car.bogies.entries().toArray().reverse()) {
+    //       currentOffset += bogie.length;
+    //       const a = this.path.followEvenPoints(this.t - currentOffset);
+    //       car.setBogiePosition(a.p, i);
+    //       this.nodes.push(a.p);
+    //       car.segments.add(a.segmentId);
+    //     }
+    //   }
+    // }
   }
 
   move(dTime: number) {
     if (!this.speed) return;
-    this.t = this.t + this.speed * dTime * 10;
+    this.t = this.t + (this.speed / this.path.pointSpacing) * dTime * 10;
     // % this.path.evenPoints.length; // This should probably be on the track system
     let currentOffset = 0;
     for (const car of this.cars) {
       // This needs to be moved to the car itself
-      if (!car.points) return;
+      // if (!car.points) return;
-      const [a, b] = car.points;
+      // const [a, b] = car.points;
-      const nA = this.path.followEvenPoints(this.t - currentOffset);
+      // const nA = this.path.followEvenPoints(this.t - currentOffset);
-      a.set(nA.p);
+      // a.set(nA.p);
-      currentOffset += car.length;
+      // currentOffset += car.length;
-      const nB = this.path.followEvenPoints(this.t - currentOffset);
+      // const nB = this.path.followEvenPoints(this.t - currentOffset);
-      b.set(nB.p);
+      // b.set(nB.p);
-      currentOffset += this.spacing;
+      // currentOffset += this.spacing;
-      car.segments = [nA.segmentId, nB.segmentId];
+      // car.segments = [nA.segmentId, nB.segmentId];
       // car.draw();
+
+      currentOffset += car.moveAlongPath(this.t - currentOffset) +
+        this.spacing / this.path.pointSpacing +
+        car.leading / this.path.pointSpacing;
     }
     // this.draw();
   }
@@ -118,7 +124,7 @@ export class Train extends Debuggable {
       colors.push(colors.shift()!);
       colors.push(colors.shift()!);
       colors.push(colors.shift()!);
-      for (const [i, segmentId] of this.segments.entries()) {
+      for (const [i, segmentId] of this.segments.entries().toArray()) {
         const segment = track.getSegment(segmentId);
         segment &&
           doodler.drawBezier(...segment.points, {
@@ -134,6 +140,14 @@ export class Train extends Debuggable {
   }
 }
 
+interface Bogie {
+  pos: Vector;
+  angle: number;
+  length: number;
+  sprite?: ISprite & { offset?: Vector };
+  rotate?: boolean;
+}
+
 export class TrainCar extends Debuggable {
   img: HTMLImageElement;
   imgWidth: number;
@@ -141,31 +155,83 @@ export class TrainCar extends Debuggable {
   sprite?: ISprite;
 
   points?: [Vector, Vector, ...Vector[]];
-  length: number;
+  _length: number;
+  leading: number = 0;
 
-  segments: string[] = [];
+  bogies: Bogie[] = [];
+
+  segments: Set<string> = new Set();
+
+  train?: Train;
 
   constructor(
     length: number,
+    trailing: number,
     img: HTMLImageElement,
     w: number,
     h: number,
     sprite?: ISprite,
   ) {
-    super(true, "car");
+    super(true, "car", "bogies", "angles");
     this.img = img;
     this.sprite = sprite;
     this.imgWidth = w;
     this.imgHeight = h;
-    this.length = length;
+    this._length = length;
+
+    this.bogies = [
+      {
+        pos: new Vector(0, 0),
+        angle: 0,
+        length: length,
+      },
+      {
+        pos: new Vector(0, 0),
+        angle: 0,
+        length: trailing,
+      },
+    ];
+  }
+
+  get length() {
+    return this.bogies.reduce((acc, b) => acc + b.length, 0) + this.leading;
+  }
+
+  setBogiePosition(pos: Vector, idx: number) {
+    this.bogies[idx].pos.set(pos);
+  }
+
+  update(dTime: number, t: number) {
+    if (this.train) {
+      for (const [i, bogie] of this.bogies.entries()) {
+        const a = this.train.path.followEvenPoints(t - this._length * i);
+      }
+    }
+  }
+
+  moveAlongPath(t: number, initial = false): number {
+    if (!this.train) return 0;
+    let offset = this.leading / this.train.path.pointSpacing;
+    this.segments.clear();
+    for (const [i, bogie] of this.bogies.entries()) {
+      const a = this.train.path.followEvenPoints(t - offset);
+      a.tangent.rotate(TWO_PI);
+      offset += bogie.length / this.train.path.pointSpacing;
+      this.setBogiePosition(a.p, i);
+      if (initial) bogie.angle = a.tangent.heading();
+      else {
+        bogie.angle = lerpAngle(a.tangent.heading(), bogie.angle, .1);
+      }
+      this.segments.add(a.segmentId);
+    }
+    return offset;
   }
 
   draw() {
-    if (!this.points) return;
     const doodler = getContextItem<Doodler>("doodler");
-    const [a, b] = this.points;
+    const [a, b] = this.bogies;
-    const origin = Vector.add(Vector.sub(a, b).div(2), b);
+    const origin = Vector.add(Vector.sub(a.pos, b.pos).div(2), b.pos);
-    const angle = Vector.sub(b, a).heading();
+    const angle = Vector.sub(b.pos, a.pos).heading();
 
     doodler.drawCircle(origin, 4, { color: "blue" });
 
@@ -187,13 +253,74 @@ export class TrainCar extends Debuggable {
     });
   }
   override debugDraw(...args: unknown[]): void {
-    if (!this.points) return;
     const doodler = getContextItem<Doodler>("doodler");
-    doodler.drawLine(this.points, {
+    const debug = getContextItem<Debug>("debug");
-      color: "blue",
+    if (debug.bogies) {
-      weight: 3,
+      doodler.deferDrawing(() => {
+        for (const [i, b] of this.bogies.entries()) {
+          const next = this.bogies[i + 1];
+          if (!next) continue;
+          const dist = Vector.dist(b.pos, next.pos);
+          doodler.drawCircle(b.pos, 5, { color: "red" });
+          doodler.fillText(
+            dist.toFixed(1).toString(),
+            b.pos.copy().add(10, 10),
+            100,
+            {
+              color: "white",
+            },
+          );
+        }
       });
     }
+    if (debug.car) {
+      doodler.deferDrawing(() => {
+        doodler.drawLine(this.bogies.map((b) => b.pos), {
+          color: "blue",
+          weight: 2,
+        });
+        doodler.deferDrawing(() => {
+          const colors = getContextItem<string[]>("colors");
+          for (const [i, b] of this.bogies.entries()) {
+            doodler.drawCircle(b.pos, 5, { color: colors[i % colors.length] });
+            doodler.fillText(
+              b.length.toString(),
+              b.pos.copy().add(10, 0),
+              100,
+              {
+                color: "white",
+              },
+            );
+          }
+        });
+      });
+    }
+
+    if (debug.angles) {
+      doodler.deferDrawing(() => {
+        const ps: { pos: Vector; angle: number }[] = [];
+        for (const [i, b] of this.bogies.entries()) {
+          ps.push({ pos: b.pos, angle: b.angle });
+          const next = this.bogies[i + 1];
+          if (!next) continue;
+          const heading = Vector.sub(next.pos, b.pos);
+          const p = b.pos.copy().add(heading.mult(.5));
+          ps.push({ pos: p, angle: heading.heading() });
+        }
+        for (const p of ps) {
+          doodler.dot(p.pos, { color: "green" });
+          doodler.fillText(
+            p.angle.toFixed(2).toString(),
+            p.pos.copy().add(0, 20),
+            100,
+            {
+              color: "white",
+            },
+          );
+        }
+      });
+    }
+  }
 }
 
 interface ISprite {

src/types.ts

@@ -21,5 +21,7 @@ declare global {
     train: boolean;
     car: boolean;
     path: boolean;
+    bogies: boolean;
+    angles: boolean;
   };
 }

temp.json

@@ -0,0 +1 @@
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