Add neat based lunar landing
This commit is contained in:
Peter Stockings
186
src/apps/LunarLander/LanderSimulation.ts
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186
src/apps/LunarLander/LanderSimulation.ts
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import Matter from 'matter-js';
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export const WORLD_WIDTH = 800;
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export const WORLD_HEIGHT = 600;
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const LANDER_WIDTH = 30;
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const LANDER_HEIGHT = 40;
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const PAD_WIDTH = 80;
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export class LanderSimulation {
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public engine: Matter.Engine;
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public lander!: Matter.Body;
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public ground!: Matter.Body;
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public pad!: Matter.Body;
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public isGameOver = false;
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public result: 'FLYING' | 'CRASHED' | 'LANDED' | 'TIMEOUT' = 'FLYING';
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// State
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public fuel = 1000;
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public readonly maxFuel = 1000;
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public timeSteps = 0;
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public readonly maxTimeSteps = 60 * 20; // 20s
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public currentWind = 0;
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public currentMainPower = 0;
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public currentNozzleAngle = 0;
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public lastActions: number[] = [0, 0];
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// Config
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private readonly DRY_MASS = 10;
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private readonly FUEL_MASS_CAPACITY = 10;
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private readonly LAG_FACTOR = 0.05;
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private readonly GIMBAL_SPEED = 0.05;
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private windTime = Math.random() * 100;
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constructor(seed: number = 0) {
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this.engine = Matter.Engine.create({ enableSleeping: false });
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this.engine.gravity.y = 0.5;
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// Custom PRNG
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let s = seed;
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const random = () => {
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s = (s * 9301 + 49297) % 233280;
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return s / 233280;
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};
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this.setupWorld(random);
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Matter.Events.on(this.engine, 'collisionStart', (e) => this.handleCollisions(e));
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}
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private setupWorld(random: () => number) {
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// Bodies
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this.ground = Matter.Bodies.rectangle(WORLD_WIDTH/2, WORLD_HEIGHT, WORLD_WIDTH, 20, {
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isStatic: true, label: 'ground', friction: 1, render: { fillStyle: '#555555' }
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});
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this.pad = Matter.Bodies.rectangle(WORLD_WIDTH/2, WORLD_HEIGHT - 30, PAD_WIDTH, 10, {
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isStatic: true, label: 'pad', render: { fillStyle: '#00ff00' }
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});
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const startX = 100 + random() * (WORLD_WIDTH - 200);
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const startY = 50 + random() * 100;
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this.lander = Matter.Bodies.trapezoid(startX, startY, LANDER_WIDTH, LANDER_HEIGHT, 0.5, {
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friction: 0.1, frictionAir: 0.02, restitution: 0, label: 'lander', angle: 0
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});
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Matter.Body.setMass(this.lander, this.DRY_MASS + this.FUEL_MASS_CAPACITY);
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Matter.Body.setVelocity(this.lander, { x: (random() - 0.5) * 4, y: 0 });
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Matter.World.add(this.engine.world, [this.ground, this.pad, this.lander]);
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}
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private handleCollisions(event: Matter.IEventCollision<Matter.Engine>) {
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if (this.isGameOver) return;
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event.pairs.forEach(pair => {
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const other = pair.bodyA === this.lander ? pair.bodyB : (pair.bodyB === this.lander ? pair.bodyA : null);
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if (!other) return;
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if (other.label === 'pad') this.checkLanding();
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else if (other.label === 'ground') this.crash("Hit ground");
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});
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}
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private checkLanding() {
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const { position, velocity, angle, angularVelocity } = this.lander;
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const speed = Math.hypot(velocity.x, velocity.y);
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// Strict Bounds Check
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const isAbovePad = position.y < (this.pad.position.y - 15);
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const isOnPad = Math.abs(position.x - this.pad.position.x) < 35; // Inside pad width
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if (!isAbovePad) return this.crash("Hit side of pad");
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if (!isOnPad) return this.crash("Missed center");
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// Landing Criteria
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if (speed < 2.5 && Math.abs(angle) < 0.25 && Math.abs(angularVelocity) < 0.15) {
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this.result = 'LANDED';
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this.isGameOver = true;
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} else {
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this.crash(`Too fast/tilted: Spd=${speed.toFixed(1)}`);
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}
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}
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private crash(reason: string) {
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this.result = 'CRASHED';
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this.isGameOver = true;
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}
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public update(actions: number[]): boolean {
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this.lastActions = actions;
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if (this.isGameOver) return false;
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if (++this.timeSteps > this.maxTimeSteps) {
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this.result = 'TIMEOUT';
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this.isGameOver = true;
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return false;
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}
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this.applyWind();
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this.updateMass();
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this.applyControls(actions);
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this.checkBounds();
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Matter.Engine.update(this.engine, 1000 / 60);
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return !this.isGameOver;
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}
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private applyWind() {
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this.windTime += 0.01;
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this.currentWind = Math.sin(this.windTime) + Math.sin(this.windTime * 3.2) * 0.5 + Math.sin(this.windTime * 0.7) * 2.0;
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Matter.Body.applyForce(this.lander, this.lander.position, { x: this.currentWind * 0.002, y: 0 });
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}
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private updateMass() {
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const expectedMass = this.DRY_MASS + (this.fuel / this.maxFuel) * this.FUEL_MASS_CAPACITY;
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if (Math.abs(this.lander.mass - expectedMass) > 0.01) {
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Matter.Body.setMass(this.lander, expectedMass);
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}
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}
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private applyControls(actions: number[]) {
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// [0: Thrust (-1..1), 1: Nozzle (-1..1)]
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let targetMainPower = Math.max(0, Math.min(1, (actions[0] + 1) / 2));
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const targetNozzleAngle = actions[1] * 0.5; // Max 0.5 rad (~28 deg)
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// Lag & Inertia
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this.currentMainPower += Math.sign(targetMainPower - this.currentMainPower) * Math.min(Math.abs(targetMainPower - this.currentMainPower), this.LAG_FACTOR);
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this.currentNozzleAngle += Math.sign(targetNozzleAngle - this.currentNozzleAngle) * Math.min(Math.abs(targetNozzleAngle - this.currentNozzleAngle), this.GIMBAL_SPEED);
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// Fuel
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if (this.fuel <= 0) this.currentMainPower = 0;
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else this.fuel -= this.currentMainPower * 0.5;
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// Apply Force
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if (this.currentMainPower > 0.01) {
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const force = 0.0005 * 20 * 2.5 * this.currentMainPower; // 2.5TWR approx
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const totalAngle = this.lander.angle + this.currentNozzleAngle;
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const forceVector = { x: Math.sin(totalAngle) * force, y: -Math.cos(totalAngle) * force };
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// Offset point (bottom of lander)
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const appPos = Matter.Vector.add(this.lander.position, Matter.Vector.rotate({ x: 0, y: 20 }, this.lander.angle));
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Matter.Body.applyForce(this.lander, appPos, forceVector);
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}
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}
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private checkBounds() {
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if (this.lander.position.x < -100 || this.lander.position.x > WORLD_WIDTH + 100 ||
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this.lander.position.y < -500 || this.lander.position.y > WORLD_HEIGHT + 100) {
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this.crash("Out of bounds");
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}
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}
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public getObservation(): number[] {
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const { velocity, angularVelocity, position, angle } = this.lander;
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return [
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velocity.x / 10.0,
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velocity.y / 10.0,
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angle / 3.14,
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angularVelocity / 0.5,
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(position.x - this.pad.position.x) / WORLD_WIDTH,
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(position.y - this.pad.position.y) / WORLD_HEIGHT,
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this.currentWind / 5.0,
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this.currentNozzleAngle / 0.5,
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];
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}
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}
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