denchhq App Game Builder
This skill covers building 2D and 3D games as DenchClaw apps. For core app structure, manifest reference, and bridge API basics, see the parent app-builder skill (app-builder/SKILL.md).
2D Games with p5.js
Always use p5.js for 2D games, simulations, generative art, and interactive 2D experiences. p5.js is the default choice for anything 2D unless the user specifically requests something else.
When to Use p5.js
- 2D games (platformer, puzzle, arcade, card games, board games)
- Generative art and creative coding
- Physics simulations and particle systems
- Interactive data visualizations with animation
- Educational simulations and demonstrations
- Drawing and painting tools
- Any 2D canvas-based interactive experience
p5.js App Template
apps/my-game.dench.app/
.dench.yaml
index.html
sketch.js
assets/ # sprites, sounds, fonts
.dench.yaml:
name: "My Game"
description: "A fun 2D game built with p5.js"
icon: "gamepad-2"
version: "1.0.0"
entry: "index.html"
runtime: "static"
No permissions needed unless the game reads/writes workspace data.
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>My Game</title>
<script src="https://unpkg.com/p5@1/lib/p5.min.js"></script>
<style>
* {
margin: 0;
padding: 0;
}
html,
body {
width: 100%;
height: 100%;
overflow: hidden;
}
body {
display: flex;
align-items: center;
justify-content: center;
background: #0f0f1a;
}
canvas {
display: block;
}
</style>
</head>
<body>
<script src="sketch.js"></script>
</body>
</html>
sketch.js (game loop skeleton):
let isDark = true;
function setup() {
createCanvas(windowWidth, windowHeight);
// Detect theme from DenchClaw
if (window.dench) {
window.dench.app
.getTheme()
.then((theme) => {
isDark = theme === "dark";
})
.catch(() => {});
}
}
function draw() {
background(isDark ? 15 : 245);
// Game rendering goes here
}
function windowResized() {
resizeCanvas(windowWidth, windowHeight);
}
p5.js Instance Mode (Recommended for Complex Apps)
Use instance mode to avoid global namespace pollution. This is especially important for multi-file apps:
const sketch = (p) => {
let isDark = true;
let player;
p.setup = () => {
p.createCanvas(p.windowWidth, p.windowHeight);
player = { x: p.width / 2, y: p.height / 2, size: 30, speed: 4 };
if (window.dench) {
window.dench.app
.getTheme()
.then((theme) => {
isDark = theme === "dark";
})
.catch(() => {});
}
};
p.draw = () => {
p.background(isDark ? 15 : 245);
// Input handling
if (p.keyIsDown(p.LEFT_ARROW) || p.keyIsDown(65)) player.x -= player.speed;
if (p.keyIsDown(p.RIGHT_ARROW) || p.keyIsDown(68)) player.x += player.speed;
if (p.keyIsDown(p.UP_ARROW) || p.keyIsDown(87)) player.y -= player.speed;
if (p.keyIsDown(p.DOWN_ARROW) || p.keyIsDown(83)) player.y += player.speed;
// Keep in bounds
player.x = p.constrain(player.x, 0, p.width);
player.y = p.constrain(player.y, 0, p.height);
// Draw player
p.fill(isDark ? "#6366f1" : "#4f46e5");
p.noStroke();
p.ellipse(player.x, player.y, player.size);
};
p.windowResized = () => {
p.resizeCanvas(p.windowWidth, p.windowHeight);
};
};
new p5(sketch);
p5.js Game Architecture Patterns
Game State Machine
const GameState = { MENU: "menu", PLAYING: "playing", PAUSED: "paused", GAME_OVER: "gameover" };
let state = GameState.MENU;
let score = 0;
let highScore = 0;
function draw() {
switch (state) {
case GameState.MENU:
drawMenu();
break;
case GameState.PLAYING:
drawGame();
break;
case GameState.PAUSED:
drawPause();
break;
case GameState.GAME_OVER:
drawGameOver();
break;
}
}
function keyPressed() {
if (state === GameState.MENU && (key === " " || key === "Enter")) {
state = GameState.PLAYING;
resetGame();
} else if (state === GameState.PLAYING && key === "Escape") {
state = GameState.PAUSED;
} else if (state === GameState.PAUSED && key === "Escape") {
state = GameState.PLAYING;
} else if (state === GameState.GAME_OVER && (key === " " || key === "Enter")) {
state = GameState.PLAYING;
resetGame();
}
}
function drawMenu() {
background(15);
fill(255);
textAlign(CENTER, CENTER);
textSize(48);
text("MY GAME", width / 2, height / 2 - 60);
textSize(18);
fill(150);
text("Press SPACE or ENTER to start", width / 2, height / 2 + 20);
if (highScore > 0) {
textSize(14);
text("High Score: " + highScore, width / 2, height / 2 + 60);
}
}
function drawGameOver() {
background(15);
fill("#ef4444");
textAlign(CENTER, CENTER);
textSize(48);
text("GAME OVER", width / 2, height / 2 - 60);
fill(255);
textSize(24);
text("Score: " + score, width / 2, height / 2);
textSize(16);
fill(150);
text("Press SPACE to play again", width / 2, height / 2 + 50);
}
Sprite Management
class Sprite {
constructor(x, y, w, h) {
this.pos = createVector(x, y);
this.vel = createVector(0, 0);
this.w = w;
this.h = h;
this.alive = true;
}
update() {
this.pos.add(this.vel);
}
draw() {
rectMode(CENTER);
rect(this.pos.x, this.pos.y, this.w, this.h);
}
collidesWith(other) {
return (
this.pos.x - this.w / 2 < other.pos.x + other.w / 2 &&
this.pos.x + this.w / 2 > other.pos.x - other.w / 2 &&
this.pos.y - this.h / 2 < other.pos.y + other.h / 2 &&
this.pos.y + this.h / 2 > other.pos.y - other.h / 2
);
}
isOffscreen() {
return (
this.pos.x < -this.w ||
this.pos.x > width + this.w ||
this.pos.y < -this.h ||
this.pos.y > height + this.h
);
}
}
Particle System
class Particle {
constructor(x, y, color) {
this.pos = createVector(x, y);
this.vel = p5.Vector.random2D().mult(random(1, 5));
this.acc = createVector(0, 0.1);
this.color = color;
this.alpha = 255;
this.size = random(3, 8);
this.life = 1.0;
this.decay = random(0.01, 0.04);
}
update() {
this.vel.add(this.acc);
this.pos.add(this.vel);
this.life -= this.decay;
this.alpha = this.life * 255;
}
draw() {
noStroke();
fill(red(this.color), green(this.color), blue(this.color), this.alpha);
ellipse(this.pos.x, this.pos.y, this.size);
}
isDead() {
return this.life <= 0;
}
}
let particles = [];
function spawnExplosion(x, y, col, count = 30) {
for (let i = 0; i < count; i++) {
particles.push(new Particle(x, y, col));
}
}
function updateParticles() {
for (let i = particles.length - 1; i >= 0; i--) {
particles[i].update();
particles[i].draw();
if (particles[i].isDead()) particles.splice(i, 1);
}
}
Camera / Scrolling
let camera = { x: 0, y: 0 };
function draw() {
background(15);
// Follow player
camera.x = lerp(camera.x, player.x - width / 2, 0.1);
camera.y = lerp(camera.y, player.y - height / 2, 0.1);
push();
translate(-camera.x, -camera.y);
// Draw world (in world coordinates)
drawWorld();
drawPlayer();
drawEnemies();
pop();
// Draw HUD (in screen coordinates)
drawHUD();
}
Tilemap Rendering
const TILE_SIZE = 32;
const tilemap = [
[1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 2, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 3, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1],
];
const TILE_COLORS = {
0: null, // empty
1: "#4a4a6a", // wall
2: "#22c55e", // item
3: "#ef4444", // enemy
};
function drawTilemap() {
for (let row = 0; row < tilemap.length; row++) {
for (let col = 0; col < tilemap[row].length; col++) {
const tile = tilemap[row][col];
if (TILE_COLORS[tile]) {
fill(TILE_COLORS[tile]);
noStroke();
rect(col * TILE_SIZE, row * TILE_SIZE, TILE_SIZE, TILE_SIZE);
}
}
}
}
Sound Effects (using p5.sound or Howler.js)
For sound, prefer Howler.js since p5.sound adds significant bundle size:
<script src="https://unpkg.com/howler@2/dist/howler.min.js"></script>
const sounds = {
jump: new Howl({ src: ["assets/jump.wav"], volume: 0.5 }),
hit: new Howl({ src: ["assets/hit.wav"], volume: 0.7 }),
coin: new Howl({ src: ["assets/coin.wav"], volume: 0.4 }),
music: new Howl({ src: ["assets/music.mp3"], loop: true, volume: 0.3 }),
};
If no sound assets are available, generate simple audio with Tone.js or the Web Audio API:
function playBeep(freq = 440, duration = 0.1) {
const ctx = new (window.AudioContext || window.webkitAudioContext)();
const osc = ctx.createOscillator();
const gain = ctx.createGain();
osc.connect(gain);
gain.connect(ctx.destination);
osc.frequency.value = freq;
gain.gain.setValueAtTime(0.3, ctx.currentTime);
gain.gain.exponentialRampToValueAtTime(0.001, ctx.currentTime + duration);
osc.start();
osc.stop(ctx.currentTime + duration);
}
p5.js with Physics (Matter.js)
For games needing realistic 2D physics (platformers, ragdoll, pinball):
<script src="https://unpkg.com/p5@1/lib/p5.min.js"></script>
<script src="https://unpkg.com/matter-js@0.20/build/matter.min.js"></script>
const { Engine, World, Bodies, Body, Events } = Matter;
let engine, world;
let ground, player;
function setup() {
createCanvas(windowWidth, windowHeight);
engine = Engine.create();
world = engine.world;
ground = Bodies.rectangle(width / 2, height - 20, width, 40, { isStatic: true });
player = Bodies.circle(width / 2, height / 2, 20, { restitution: 0.5 });
World.add(world, [ground, player]);
}
function draw() {
Engine.update(engine);
background(15);
// Draw ground
fill("#4a4a6a");
rectMode(CENTER);
rect(ground.position.x, ground.position.y, width, 40);
// Draw player
fill("#6366f1");
ellipse(player.position.x, player.position.y, 40);
}
function keyPressed() {
if (key === " ") {
Body.applyForce(player, player.position, { x: 0, y: -0.05 });
}
}
p5.js Responsive Canvas
Always handle window resizing and use the full viewport:
function setup() {
createCanvas(windowWidth, windowHeight);
}
function windowResized() {
resizeCanvas(windowWidth, windowHeight);
}
For fixed-aspect-ratio games (e.g., retro pixel games), scale the canvas:
const GAME_W = 320;
const GAME_H = 240;
let scaleFactor;
function setup() {
createCanvas(windowWidth, windowHeight);
pixelDensity(1);
noSmooth();
calcScale();
}
function calcScale() {
scaleFactor = min(windowWidth / GAME_W, windowHeight / GAME_H);
}
function draw() {
background(0);
push();
translate((width - GAME_W * scaleFactor) / 2, (height - GAME_H * scaleFactor) / 2);
scale(scaleFactor);
// All game drawing at GAME_W x GAME_H logical resolution
drawGameWorld();
pop();
}
function windowResized() {
resizeCanvas(windowWidth, windowHeight);
calcScale();
}
Touch / Mobile Input for p5.js Games
let touchActive = false;
let touchX = 0,
touchY = 0;
function touchStarted() {
touchActive = true;
touchX = mouseX;
touchY = mouseY;
return false; // prevent default
}
function touchMoved() {
touchX = mouseX;
touchY = mouseY;
return false;
}
function touchEnded() {
touchActive = false;
return false;
}
// Unified input: works for both mouse and touch
function getInputX() {
return mouseX;
}
function getInputY() {
return mouseY;
}
function isInputActive() {
return mouseIsPressed || touchActive;
}
p5.js High Score Persistence with DuckDB
If the game has a database permission, persist high scores:
async function loadHighScore() {
try {
await window.dench.db.execute(`
CREATE TABLE IF NOT EXISTS game_scores (
game TEXT, score INTEGER, played_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
)
`);
const result = await window.dench.db.query(
`SELECT MAX(score) as high_score FROM game_scores WHERE game = 'my-game'`,
);
return result.rows?.[0]?.high_score || 0;
} catch {
return 0;
}
}
async function saveScore(score) {
try {
await window.dench.db.execute(
`INSERT INTO game_scores (game, score) VALUES ('my-game', ${score})`,
);
} catch {}
}
3D Games & Experiences with Three.js
Always use Three.js for 3D games, visualizations, and interactive 3D experiences. Three.js is the default choice for anything 3D.
When to Use Three.js
- 3D games (first-person, third-person, flying, racing)
- 3D product viewers and configurators
- Terrain and world visualization
- 3D data visualization (3D scatter plots, network graphs)
- Architectural walkthroughs
- Generative 3D art
- Physics-based 3D simulations
Three.js App Template
apps/my-3d-app.dench.app/
.dench.yaml
index.html
app.js # Main Three.js module
assets/
model.glb # 3D models (optional)
texture.jpg # Textures (optional)
.dench.yaml:
name: "3D World"
description: "An interactive 3D experience"
icon: "box"
version: "1.0.0"
entry: "index.html"
runtime: "static"
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>3D World</title>
<script type="importmap">
{
"imports": {
"three": "https://unpkg.com/three@0.170/build/three.module.js",
"three/addons/": "https://unpkg.com/three@0.170/examples/jsm/"
}
}
</script>
<style>
* {
margin: 0;
padding: 0;
}
html,
body {
width: 100%;
height: 100%;
overflow: hidden;
}
canvas {
display: block;
}
#loading {
position: fixed;
inset: 0;
display: flex;
align-items: center;
justify-content: center;
background: #0f0f1a;
color: #e8e8f0;
font-family: -apple-system, BlinkMacSystemFont, sans-serif;
font-size: 18px;
z-index: 10;
transition: opacity 0.5s;
}
#loading.hidden {
opacity: 0;
pointer-events: none;
}
</style>
</head>
<body>
<div id="loading">Loading...</div>
<script type="module" src="app.js"></script>
</body>
</html>
app.js (Three.js module skeleton):
import * as THREE from "three";
import { OrbitControls } from "three/addons/controls/OrbitControls.js";
// --- Scene setup ---
const scene = new THREE.Scene();
scene.background = new THREE.Color(0x0f0f1a);
scene.fog = new THREE.Fog(0x0f0f1a, 50, 200);
const camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 0.1, 1000);
camera.position.set(0, 5, 10);
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;
renderer.toneMapping = THREE.ACESFilmicToneMapping;
renderer.toneMappingExposure = 1.0;
document.body.appendChild(renderer.domElement);
// --- Controls ---
const controls = new OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
controls.dampingFactor = 0.05;
controls.maxPolarAngle = Math.PI / 2;
// --- Lighting ---
const ambientLight = new THREE.AmbientLight(0x404060, 0.5);
scene.add(ambientLight);
const directionalLight = new THREE.DirectionalLight(0xffffff, 1.5);
directionalLight.position.set(10, 20, 10);
directionalLight.castShadow = true;
directionalLight.shadow.mapSize.set(2048, 2048);
directionalLight.shadow.camera.near = 0.5;
directionalLight.shadow.camera.far = 100;
directionalLight.shadow.camera.left = -30;
directionalLight.shadow.camera.right = 30;
directionalLight.shadow.camera.top = 30;
directionalLight.shadow.camera.bottom = -30;
scene.add(directionalLight);
// --- Ground ---
const groundGeo = new THREE.PlaneGeometry(200, 200);
const groundMat = new THREE.MeshStandardMaterial({ color: 0x1a1a2e, roughness: 0.8 });
const ground = new THREE.Mesh(groundGeo, groundMat);
ground.rotation.x = -Math.PI / 2;
ground.receiveShadow = true;
scene.add(ground);
// --- Objects ---
const geometry = new THREE.BoxGeometry(2, 2, 2);
const material = new THREE.MeshStandardMaterial({
color: 0x6366f1,
roughness: 0.3,
metalness: 0.5,
});
const cube = new THREE.Mesh(geometry, material);
cube.position.y = 1;
cube.castShadow = true;
scene.add(cube);
// --- Theme ---
if (window.dench) {
window.dench.app
.getTheme()
.then((theme) => {
if (theme === "light") {
scene.background = new THREE.Color(0xf0f0f5);
scene.fog = new THREE.Fog(0xf0f0f5, 50, 200);
groundMat.color.set(0xe8e8f0);
}
})
.catch(() => {});
}
// --- Hide loading screen ---
document.getElementById("loading")?.classList.add("hidden");
// --- Animation loop ---
const clock = new THREE.Clock();
function animate() {
requestAnimationFrame(animate);
const dt = clock.getDelta();
const elapsed = clock.getElapsedTime();
cube.rotation.y = elapsed * 0.5;
cube.position.y = 1 + Math.sin(elapsed) * 0.5;
controls.update();
renderer.render(scene, camera);
}
animate();
// --- Resize ---
window.addEventListener("resize", () => {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(window.innerWidth, window.innerHeight);
});
Three.js Common Addons
Load additional Three.js modules as needed via the import map:
// First-person controls
import { PointerLockControls } from "three/addons/controls/PointerLockControls.js";
// GLTF model loading
import { GLTFLoader } from "three/addons/loaders/GLTFLoader.js";
// Post-processing
import { EffectComposer } from "three/addons/postprocessing/EffectComposer.js";
import { RenderPass } from "three/addons/postprocessing/RenderPass.js";
import { UnrealBloomPass } from "three/addons/postprocessing/UnrealBloomPass.js";
// Environment maps
import { RGBELoader } from "three/addons/loaders/RGBELoader.js";
// Text
import { FontLoader } from "three/addons/loaders/FontLoader.js";
import { TextGeometry } from "three/addons/geometries/TextGeometry.js";
// Sky
import { Sky } from "three/addons/objects/Sky.js";
// Water
import { Water } from "three/addons/objects/Water.js";
// Physics integration (use cannon-es via CDN)
// Add to importmap: "cannon-es": "https://unpkg.com/cannon-es@0.20/dist/cannon-es.js"
import * as CANNON from "cannon-es";
Three.js First-Person Game Pattern
import * as THREE from "three";
import { PointerLockControls } from "three/addons/controls/PointerLockControls.js";
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
document.body.appendChild(renderer.domElement);
const controls = new PointerLockControls(camera, document.body);
// Click to enter pointer lock
document.addEventListener("click", () => {
if (!controls.isLocked) controls.lock();
});
// Movement state
const velocity = new THREE.Vector3();
const direction = new THREE.Vector3();
const keys = { forward: false, backward: false, left: false, right: false, jump: false };
document.addEventListener("keydown", (e) => {
switch (e.code) {
case "KeyW":
case "ArrowUp":
keys.forward = true;
break;
case "KeyS":
case "ArrowDown":
keys.backward = true;
break;
case "KeyA":
case "ArrowLeft":
keys.left = true;
break;
case "KeyD":
case "ArrowRight":
keys.right = true;
break;
case "Space":
keys.jump = true;
break;
}
});
document.addEventListener("keyup", (e) => {
switch (e.code) {
case "KeyW":
case "ArrowUp":
keys.forward = false;
break;
case "KeyS":
case "ArrowDown":
keys.backward = false;
break;
case "KeyA":
case "ArrowLeft":
keys.left = false;
break;
case "KeyD":
case "ArrowRight":
keys.right = false;
break;
case "Space":
keys.jump = false;
break;
}
});
let
const MOVE_SPEED = 50;
const JUMP_FORCE = 12;
const GRAVITY = 30;
const clock = new THREE.Clock();
function animate() {
requestAnimationFrame(animate);
const dt = Math.min(clock.getDelta(), 0.1);
if (controls.isLocked) {
// Apply friction
velocity.x -= velocity.x * 10.0 * dt;
velocity.z -= velocity.z * 10.0 * dt;
velocity.y -= GRAVITY * dt;
direction.z = Number(keys.forward) - Number(keys.backward);
direction.x = Number(keys.right) - Number(keys.left);
direction.normalize();
if (keys.forward || keys.backward) velocity.z -= direction.z * MOVE_SPEED * dt;
if (keys.left || keys.right) velocity.x -= direction.x * MOVE_SPEED * dt;
if (keys.jump && onGround) {
velocity.y = JUMP_FORCE;
}
controls.moveRight(-velocity.x * dt);
controls.moveForward(-velocity.z * dt);
camera.position.y += velocity.y * dt;
if (camera.position.y < 1.7) {
velocity.y = 0;
camera.position.y = 1.7;
}
}
renderer.render(scene, camera);
}
animate();
Three.js GLTF Model Loading
import { GLTFLoader } from "three/addons/loaders/GLTFLoader.js";
import { DRACOLoader } from "three/addons/loaders/DRACOLoader.js";
const loader = new GLTFLoader();
const dracoLoader = new DRACOLoader();
dracoLoader.setDecoderPath("https://unpkg.com/three@0.170/examples/jsm/libs/draco/");
loader.setDRACOLoader(dracoLoader);
// Load a model from the app's assets folder
loader.load(
"assets/model.glb",
(gltf) => {
const model = gltf.scene;
model.traverse((child) => {
if (child.isMesh) {
child.castShadow = true;
child.receiveShadow = true;
}
});
model.scale.setScalar(1);
scene.add(model);
// If the model has animations
if (gltf.animations.length > 0) {
const mixer = new THREE.AnimationMixer(model);
const action = mixer.clipAction(gltf.animations[0]);
action.play();
// In animate loop: mixer.update(dt);
}
},
undefined,
(error) => {
console.error("Model load error:", error);
},
);
Three.js Post-Processing (Bloom, etc.)
import { EffectComposer } from "three/addons/postprocessing/EffectComposer.js";
import { RenderPass } from "three/addons/postprocessing/RenderPass.js";
import { UnrealBloomPass } from "three/addons/postprocessing/UnrealBloomPass.js";
const composer = new EffectComposer(renderer);
composer.addPass(new RenderPass(scene, camera));
const bloomPass = new UnrealBloomPass(
new THREE.Vector2(window.innerWidth, window.innerHeight),
0.5, // strength
0.4, // radius
0.85, // threshold
);
composer.addPass(bloomPass);
// In animate loop, replace renderer.render(scene, camera) with:
// composer.render();
// On resize, also update:
// composer.setSize(window.innerWidth, window.innerHeight);
Three.js Procedural Terrain
function createTerrain(width, depth, resolution) {
const geometry = new THREE.PlaneGeometry(width, depth, resolution, resolution);
const vertices = geometry.attributes.position.array;
for (let i = 0; i < vertices.length; i += 3) {
const x = vertices[i];
const z = vertices[i + 1];
vertices[i + 2] = noise(x * 0.02, z * 0.02) * 15;
}
geometry.computeVertexNormals();
const material = new THREE.MeshStandardMaterial({
color: 0x3a7d44,
roughness: 0.9,
flatShading: true,
});
const mesh = new THREE.Mesh(geometry, material);
mesh.rotation.x = -Math.PI / 2;
mesh.receiveShadow = true;
return mesh;
}
// Simple noise function (for procedural generation without dependencies)
function noise(x, y) {
const n = Math.sin(x * 12.9898 + y * 78.233) * 43758.5453;
return n - Math.floor(n);
}
Three.js HUD / UI Overlay
Since Three.js renders to a canvas, use HTML overlays for UI:
<div
id="hud"
style="
position: fixed; top: 0; left: 0; right: 0;
padding: 16px; pointer-events: none;
font-family: -apple-system, BlinkMacSystemFont, sans-serif;
color: white; z-index: 5;
"
>
<div id="score" style="font-size: 24px; font-weight: 700;"></div>
<div
id="health-bar"
style="
width: 200px; height: 8px; border-radius: 4px;
background: rgba(255,255,255,0.2); margin-top: 8px;
"
>
<div
id="health-fill"
style="
width: 100%; height: 100%; border-radius: 4px;
background: #22c55e; transition: width 0.3s;
"
></div>
</div>
</div>
function updateHUD(score, health) {
document.getElementById("score").textContent = `Score: ${score}`;
document.getElementById("health-fill").style.width = `${health}%`;
document.getElementById("health-fill").style.background =
health > 50 ? "#22c55e" : health > 25 ? "#f59e0b" : "#ef4444";
}
Full Game Examples
Example 1: Arcade Game (p5.js)
A complete asteroid-dodge game with scoring, particles, and game states.
.dench.yaml:
name: "Asteroid Dodge"
description: "Dodge the falling asteroids! Arrow keys or WASD to move."
icon: "rocket"
version: "1.0.0"
entry: "index.html"
runtime: "static"
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Asteroid Dodge</title>
<script src="https://unpkg.com/p5@1/lib/p5.min.js"></script>
<style>
* {
margin: 0;
padding: 0;
}
html,
body {
width: 100%;
height: 100%;
overflow: hidden;
background: #0a0a1a;
}
canvas {
display: block;
}
</style>
</head>
<body>
<script src="game.js"></script>
</body>
</html>
game.js:
const State = { MENU: 0, PLAY: 1, OVER: 2 };
let state = State.MENU;
let player, asteroids, particles, stars;
let score,
highScore = 0,
spawnTimer,
difficulty;
function setup() {
createCanvas(windowWidth, windowHeight);
textFont("system-ui");
stars = Array.from({ length: 100 }, () => ({
x: random(width),
y: random(height),
s: random(1, 3),
b: random(100, 255),
}));
if (window.dench) {
window.dench.app.getTheme().catch(() => {});
}
}
function resetGame() {
player = { x: width / 2, y: height - 80, size: 24, speed: 5, lives: 3, invincible: 0 };
asteroids = [];
particles = [];
score = 0;
spawnTimer = 0;
difficulty = 1;
}
function draw() {
background(10, 10, 26);
drawStars();
switch (state) {
case State.MENU:
drawMenu();
break;
case State.PLAY:
updateGame();
drawGame();
drawHUD();
break;
case State.OVER:
drawGame();
drawHUD();
drawGameOver();
break;
}
}
function drawStars() {
noStroke();
for (const s of stars) {
fill(255, s.b);
ellipse(s.x, s.y, s.s);
s.y += s.s * 0.3;
if (s.y > height) {
s.y = 0;
s.x = random(width);
}
}
}
function drawMenu() {
fill(255);
textAlign(CENTER, CENTER);
textSize(min(width * 0.08, 56));
textStyle(BOLD);
text("ASTEROID DODGE", width / 2, height / 2 - 60);
textSize(min(width * 0.03, 18));
textStyle(NORMAL);
fill(180);
text("Arrow keys or WASD to move", width / 2, height / 2 + 10);
fill(99, 102, 241);
text("Press SPACE or ENTER to start", width / 2, height / 2 + 50);
if (highScore > 0) {
fill(120);
textSize(14);
text("High Score: " + highScore, width / 2, height / 2 + 90);
}
}
function updateGame() {
// Player movement
if (keyIsDown(LEFT_ARROW) || keyIsDown(65)) player.x -= player.speed;
if (keyIsDown(RIGHT_ARROW) || keyIsDown(68)) player.x += player.speed;
if (keyIsDown(UP_ARROW) || keyIsDown(87)) player.y -= player.speed;
if (keyIsDown(DOWN_ARROW) || keyIsDown(83)) player.y += player.speed;
player.x = constrain(player.x, player.size, width - player.size);
player.y = constrain(player.y, player.size, height - player.size);
if (player.invincible > 0) player.invincible--;
// Spawn asteroids
difficulty = 1 + score / 500;
spawnTimer++;
if (spawnTimer > max(15, 45 - difficulty * 3)) {
asteroids.push({
x: random(width),
y: -30,
size: random(15, 35),
vy: random(2, 4) * difficulty,
vx: random(-1, 1),
rot: random(TWO_PI),
rotSpeed: random(-0.05, 0.05),
});
spawnTimer = 0;
}
// Update asteroids
for (let i = asteroids.length - 1; i >= 0; i--) {
const a = asteroids[i];
a.y += a.vy;
a.x += a.vx;
a.rot += a.rotSpeed;
if (a.y > height + 50) {
asteroids.splice(i, 1);
score += 10;
continue;
}
// Collision
if (player.invincible <= 0 && dist(player.x, player.y, a.x, a.y) < player.size + a.size / 2) {
spawnParticles(a.x, a.y, color(239, 68, 68), 20);
asteroids.splice(i, 1);
player.lives--;
player.invincible = 90;
if (player.lives <= 0) {
highScore = max(highScore, score);
state = State.OVER;
}
}
}
// Update particles
for (let i = particles.length - 1; i >= 0; i--) {
const p = particles[i];
p.x += p.vx;
p.y += p.vy;
p.vy += 0.05;
p.life -= 0.02;
if (p.life <= 0) particles.splice(i, 1);
}
score++;
}
function drawGame() {
// Draw asteroids
for (const a of asteroids) {
push();
translate(a.x, a.y);
rotate(a.rot);
fill(120, 120, 140);
stroke(80, 80, 100);
strokeWeight(1);
beginShape();
for (let i = 0; i < 7; i++) {
const angle = map(i, 0, 7, 0, TWO_PI);
const r = (a.size / 2) * (0.7 + 0.3 * sin(i * 2.5));
vertex(cos(angle) * r, sin(angle) * r);
}
endShape(CLOSE);
pop();
}
// Draw particles
noStroke();
for (const p of particles) {
fill(red(p.col), green(p.col), blue(p.col), p.life * 255);
ellipse(p.x, p.y, p.size * p.life);
}
// Draw player
if (state === State.PLAY) {
if (player.invincible <= 0 || frameCount % 6 < 3) {
push();
translate(player.x, player.y);
fill(99, 102, 241);
noStroke();
triangle(
0,
-player.size,
-player.size * 0.6,
player.size * 0.6,
player.size * 0.6,
player.size * 0.6,
);
fill(129, 140, 248);
triangle(
0,
-player.size * 0.5,
-player.size * 0.3,
player.size * 0.3,
player.size * 0.3,
player.size * 0.3,
);
pop();
}
}
}
function drawHUD() {
fill(255);
noStroke();
textAlign(LEFT, TOP);
textSize(20);
textStyle(BOLD);
text("Score: " + score, 20, 20);
textStyle(NORMAL);
textSize(14);
fill(200);
for (let i = 0; i < player.lives; i++) {
fill(239, 68, 68);
ellipse(20 + i * 22, 55, 14);
}
}
function drawGameOver() {
fill(0, 0, 0, 150);
rect(0, 0, width, height);
fill(239, 68, 68);
textAlign(CENTER, CENTER);
textSize(min(width * 0.07, 48));
textStyle(BOLD);
text("GAME OVER", width / 2, height / 2 - 40);
fill(255);
textSize(22);
textStyle(NORMAL);
text("Score: " + score, width / 2, height / 2 + 10);
fill(180);
textSize(16);
text("Press SPACE to play again", width / 2, height / 2 + 50);
}
function spawnParticles(x, y, col, count) {
for (let i = 0; i < count; i++) {
const angle = random(TWO_PI);
const speed = random(1, 5);
particles.push({
x,
y,
vx: cos(angle) * speed,
vy: sin(angle) * speed,
size: random(4, 10),
col,
life: 1.0,
});
}
}
function keyPressed() {
if (state === State.MENU && (key === " " || key === "Enter")) {
state = State.PLAY;
resetGame();
} else if (state === State.OVER && (key === " " || key === "Enter")) {
state = State.PLAY;
resetGame();
}
}
function windowResized() {
resizeCanvas(windowWidth, windowHeight);
}
Example 2: 3D Scene Viewer (Three.js)
.dench.yaml:
name: "3D Playground"
description: "Interactive 3D scene with orbit controls"
icon: "box"
version: "1.0.0"
entry: "index.html"
runtime: "static"
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>3D Playground</title>
<script type="importmap">
{
"imports": {
"three": "https://unpkg.com/three@0.170/build/three.module.js",
"three/addons/": "https://unpkg.com/three@0.170/examples/jsm/"
}
}
</script>
<style>
* {
margin: 0;
padding: 0;
}
html,
body {
width: 100%;
height: 100%;
overflow: hidden;
}
canvas {
display: block;
}
</style>
</head>
<body>
<script type="module" src="scene.js"></script>
</body>
</html>
scene.js:
import * as THREE from "three";
import { OrbitControls } from "three/addons/controls/OrbitControls.js";
const scene = new THREE.Scene();
let bgColor = 0x0f0f1a;
if (window.dench) {
window.dench.app
.getTheme()
.then((t) => {
bgColor = t === "light" ? 0xf0f0f5 : 0x0f0f1a;
scene.background = new THREE.Color(bgColor);
scene.fog = new THREE.Fog(bgColor, 30, 100);
})
.catch(() => {});
}
scene.background = new THREE.Color(bgColor);
scene.fog = new THREE.Fog(bgColor, 30, 100);
const camera = new THREE.PerspectiveCamera(60, innerWidth / innerHeight, 0.1, 500);
camera.position.set(8, 6, 12);
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(innerWidth, innerHeight);
renderer.setPixelRatio(Math.min(devicePixelRatio, 2));
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;
document.body.appendChild(renderer.domElement);
const controls = new OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
scene.add(new THREE.AmbientLight(0x404060, 0.6));
const sun = new THREE.DirectionalLight(0xffffff, 1.5);
sun.position.set(10, 20, 10);
sun.castShadow = true;
sun.shadow.mapSize.set(1024, 1024);
scene.add(sun);
const ground = new THREE.Mesh(
new THREE.PlaneGeometry(60, 60),
new THREE.MeshStandardMaterial({ color: 0x1a1a2e, roughness: 0.8 }),
);
ground.rotation.x = -Math.PI / 2;
ground.receiveShadow = true;
scene.add(ground);
const shapes = [];
const colors = [0x6366f1, 0x22c55e, 0xf59e0b, 0xef4444, 0x06b6d4];
for (let i = 0; i < 12; i++) {
const geos = [
new THREE.BoxGeometry(1, 1, 1),
new THREE.SphereGeometry(0.6, 32, 32),
new THREE.ConeGeometry(0.5, 1.2, 6),
new THREE.TorusGeometry(0.5, 0.2, 16, 32),
new THREE.OctahedronGeometry(0.6),
];
const geo = geos[Math.floor(Math.random() * geos.length)];
const mat = new THREE.MeshStandardMaterial({
color: colors[Math.floor(Math.random() * colors.length)],
roughness: 0.3,
metalness: 0.5,
});
const mesh = new THREE.Mesh(geo, mat);
mesh.position.set(
(Math.random() - 0.5) * 16,
0.5 + Math.random() * 3,
(Math.random() - 0.5) * 16,
);
mesh.castShadow = true;
mesh.userData = {
baseY: mesh.position.y,
phase: Math.random() * Math.PI * 2,
rotSpeed: (Math.random() - 0.5) * 0.02,
};
scene.add(mesh);
shapes.push(mesh);
}
const clock = new THREE.Clock();
function animate() {
requestAnimationFrame(animate);
const t = clock.getElapsedTime();
for (const s of shapes) {
s.position.y = s.userData.baseY + Math.sin(t + s.userData.phase) * 0.4;
s.rotation.y += s.userData.rotSpeed;
}
controls.update();
renderer.render(scene, camera);
}
animate();
addEventListener("resize", () => {
camera.aspect = innerWidth / innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(innerWidth, innerHeight);
});