Premium Velocity Experience

if (!window.MotionPreference) {
  const __mql = window.matchMedia("(prefers-reduced-motion: reduce)");
  const __listeners = new Set();

  const MotionPreference = {
    prefersReducedMotion() {
      return __mql.matches;
    },
    setOverride(value) {
      const reduced = Boolean(value);
      document.documentElement.classList.toggle("reduced-motion", reduced);
      window.dispatchEvent(new CustomEvent("motion-preference", { detail: { reduced } }));
      for (const listener of __listeners) {
        try {
          listener({ reduced, override: reduced, systemReduced: __mql.matches });
        } catch {}
      }
    },
    onChange(listener) {
      __listeners.add(listener);
      try {
        listener({
          reduced: __mql.matches,
          override: null,
          systemReduced: __mql.matches,
        });
      } catch {}
      return () => __listeners.delete(listener);
    },
    getState() {
      return { reduced: __mql.matches, override: null, systemReduced: __mql.matches };
    },
  };

  window.MotionPreference = MotionPreference;
}

function prefersReducedMotion() {
  return window.MotionPreference.prefersReducedMotion();
}

function initDemoShell() {
  // No-op shim in imported standalone snippets.
}

import gsap from 'gsap';
import { ScrollTrigger } from 'gsap/ScrollTrigger';
import Lenis from 'lenis';

import * as THREE from 'three';

gsap.registerPlugin(ScrollTrigger);

initDemoShell({ title: 'Premium Velocity Experience', category: 'pages', tech: ['three.js', 'lenis', 'gsap', 'canvas-2d', 'velocity'] });

const reduced = prefersReducedMotion();
if (reduced) document.documentElement.classList.add('reduced-motion');

// ─── Lenis Setup ──────────────────────────────────────────────────────────────
const lenis = new Lenis({ lerp: 0.08, smoothWheel: true });
lenis.on('scroll', ScrollTrigger.update);
gsap.ticker.lagSmoothing(0);

// ─── Three.js Hero ───────────────────────────────────────────────────────────
const heroCanvas = document.getElementById('hero-canvas');
const renderer = new THREE.WebGLRenderer({ canvas: heroCanvas, alpha: true, antialias: true });
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
renderer.setSize(window.innerWidth, window.innerHeight);

const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 0.1, 100);
camera.position.z = 5;

// Icosahedron wireframe
const geo = new THREE.IcosahedronGeometry(1.8, 2);
const mat = new THREE.MeshBasicMaterial({
  color: 0x86e8ff,
  wireframe: true,
  transparent: true,
  opacity: 0.18,
});
const mesh = new THREE.Mesh(geo, mat);
scene.add(mesh);

// Inner sphere
const innerGeo = new THREE.SphereGeometry(0.9, 16, 16);
const innerMat = new THREE.MeshBasicMaterial({
  color: 0xae52ff,
  wireframe: true,
  transparent: true,
  opacity: 0.1,
});
const innerMesh = new THREE.Mesh(innerGeo, innerMat);
scene.add(innerMesh);

// Ambient particles
const particleCount = 600;
const positions = new Float32Array(particleCount * 3);
for (let i = 0; i < particleCount; i++) {
  positions[i * 3] = (Math.random() - 0.5) * 20;
  positions[i * 3 + 1] = (Math.random() - 0.5) * 20;
  positions[i * 3 + 2] = (Math.random() - 0.5) * 10;
}
const partGeo = new THREE.BufferGeometry();
partGeo.setAttribute('position', new THREE.BufferAttribute(positions, 3));
const partMat = new THREE.PointsMaterial({ color: 0x86e8ff, size: 0.03, transparent: true, opacity: 0.4 });
const particles = new THREE.Points(partGeo, partMat);
scene.add(particles);

// Scroll-driven rotation
let scrollProgress = 0;
ScrollTrigger.create({
  trigger: document.body,
  start: 'top top',
  end: 'bottom bottom',
  onUpdate: (self) => { scrollProgress = self.progress; },
});

window.addEventListener('resize', () => {
  camera.aspect = window.innerWidth / window.innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(window.innerWidth, window.innerHeight);
});

// ─── Velocity Canvas (Demo 39 technique) ─────────────────────────────────────
const velCanvas = document.getElementById('velocity-canvas');
const ctx = velCanvas.getContext('2d');
let velocity = 0;
let smoothVelocity = 0;

function resizeVelCanvas() {
  velCanvas.width = window.innerWidth;
  velCanvas.height = window.innerHeight;
}
resizeVelCanvas();
window.addEventListener('resize', resizeVelCanvas);

function drawSpeedLines(vel) {
  const cx = velCanvas.width / 2;
  const cy = velCanvas.height / 2;
  const absVel = Math.abs(vel);
  const count = Math.floor(Math.min(80, absVel * 5));
  const opacity = Math.min(0.65, absVel * 0.045);
  const maxLen = Math.min(velCanvas.width, velCanvas.height) * 0.45 * Math.min(1, absVel * 0.025);

  ctx.clearRect(0, 0, velCanvas.width, velCanvas.height);
  if (count < 1 || opacity < 0.02) return;

  for (let i = 0; i < count; i++) {
    const angle = (i / count) * Math.PI * 2;
    const minR = 60;
    const sx = cx + Math.cos(angle) * minR;
    const sy = cy + Math.sin(angle) * minR;
    const ex = cx + Math.cos(angle) * (minR + maxLen);
    const ey = cy + Math.sin(angle) * (minR + maxLen);

    const grad = ctx.createLinearGradient(sx, sy, ex, ey);
    grad.addColorStop(0, `rgba(134, 232, 255, ${opacity})`);
    grad.addColorStop(0.5, `rgba(174, 82, 255, ${opacity * 0.5})`);
    grad.addColorStop(1, 'rgba(134, 232, 255, 0)');

    ctx.beginPath();
    ctx.moveTo(sx, sy);
    ctx.lineTo(ex, ey);
    ctx.strokeStyle = grad;
    ctx.lineWidth = Math.max(0.5, absVel * 0.12);
    ctx.stroke();
  }
}

// Speed indicator UI
const speedFill = document.getElementById('speed-fill');
const speedValue = document.getElementById('speed-value');

// ─── Lenis scroll event ───────────────────────────────────────────────────────
lenis.on('scroll', (e) => {
  velocity = e.velocity;

  // Update speed UI
  const absVel = Math.abs(velocity);
  const pct = Math.min(100, absVel * 6);
  if (speedFill) speedFill.style.width = pct + '%';
  if (speedValue) speedValue.textContent = absVel.toFixed(1);
});

// ─── Main Animation Loop ──────────────────────────────────────────────────────
gsap.ticker.add((time) => {
  lenis.raf(time * 1000);

  // Smooth velocity decay
  smoothVelocity += (velocity - smoothVelocity) * 0.1;
  velocity *= 0.92;

  if (!reduced) {
    // Draw speed lines
    drawSpeedLines(smoothVelocity);

    // Rotate Three.js meshes
    const t = time * 0.3;
    mesh.rotation.x = t * 0.4 + scrollProgress * Math.PI * 2;
    mesh.rotation.y = t * 0.6;
    innerMesh.rotation.x = -t * 0.5;
    innerMesh.rotation.y = t * 0.8 + scrollProgress * Math.PI;
    particles.rotation.y = t * 0.08;

    // Velocity effect on mesh scale
    const absVel = Math.abs(smoothVelocity);
    const scalePulse = 1 + absVel * 0.008;
    mesh.scale.setScalar(scalePulse);
  }

  renderer.render(scene, camera);
});

// ─── Gradient hue shift on scroll ────────────────────────────────────────────
if (!reduced) {
  ScrollTrigger.create({
    trigger: document.body,
    start: 'top top',
    end: 'bottom bottom',
    onUpdate: (self) => {
      document.documentElement.style.setProperty('--hue-shift', `${self.progress * 300}deg`);
    },
  });
}

// ─── Hero entrance ────────────────────────────────────────────────────────────
if (!reduced) {
  gsap.set(['.hero-tag', '.hero h1', '.hero-desc', '.speed-indicator'], { opacity: 0, y: 30 });
  gsap.timeline({ defaults: { ease: 'expo.out' } })
    .to('.hero-tag', { opacity: 1, y: 0, duration: 0.7, delay: 0.5 })
    .to('.hero h1', { opacity: 1, y: 0, duration: 1 }, '-=0.4')
    .to('.hero-desc', { opacity: 1, y: 0, duration: 0.7 }, '-=0.5')
    .to('.speed-indicator', { opacity: 1, y: 0, duration: 0.6 }, '-=0.4');
}

// ─── Depth cards entrance (Demo 38 technique) ─────────────────────────────────
document.querySelectorAll('.depth-card').forEach((card, i) => {
  const depth = parseFloat(card.style.getPropertyValue('--depth')) || 0.5;

  if (!reduced) {
    gsap.set(card, { opacity: 0, y: 60, rotationX: 15, scale: 0.85 });
    gsap.to(card, {
      opacity: 1,
      y: 0,
      rotationX: 0,
      scale: 1,
      duration: 1,
      ease: 'expo.out',
      delay: depth * 0.3,
      scrollTrigger: { trigger: '.depth-section', start: 'top 70%', toggleActions: 'play none none reverse' },
    });

    card.addEventListener('mouseenter', () => gsap.to(card, { y: -12, duration: 0.4, overwrite: 'auto' }));
    card.addEventListener('mouseleave', () => gsap.to(card, { y: 0, duration: 0.4, overwrite: 'auto' }));
  }
});

// ─── Stats counters ───────────────────────────────────────────────────────────
document.querySelectorAll('.stat-card').forEach((card, i) => {
  const valEl = card.querySelector('.stat-value');
  const target = parseFloat(card.dataset.target);
  const suffix = card.dataset.suffix || '';

  if (!reduced) {
    gsap.set(card, { opacity: 0, y: 30 });
    gsap.to(card, {
      opacity: 1,
      y: 0,
      duration: 0.7,
      ease: 'expo.out',
      delay: i * 0.08,
      scrollTrigger: { trigger: '.stats-grid', start: 'top 75%', toggleActions: 'play none none reverse' },
    });

    ScrollTrigger.create({
      trigger: card,
      start: 'top 80%',
      end: 'top 25%',
      onUpdate: (self) => {
        const val = target * self.progress;
        const display = target % 1 !== 0 ? val.toFixed(1) : Math.round(val);
        valEl.textContent = display + suffix;
      },
    });
  } else {
    valEl.textContent = target + suffix;
  }
});

// ─── Features list ────────────────────────────────────────────────────────────
document.querySelectorAll('.feature-item').forEach((item, i) => {
  if (!reduced) {
    gsap.set(item, { opacity: 0, x: -30 });
    gsap.to(item, {
      opacity: 1,
      x: 0,
      duration: 0.8,
      ease: 'expo.out',
      delay: i * 0.1,
      scrollTrigger: { trigger: item, start: 'top 75%', toggleActions: 'play none none reverse' },
    });
  }
});

// Section headers
document.querySelectorAll('.section-header').forEach((h) => {
  if (!reduced) {
    gsap.set(h.children, { opacity: 0, y: 25 });
    gsap.to(h.children, {
      opacity: 1, y: 0, duration: 0.7, stagger: 0.1, ease: 'expo.out',
      scrollTrigger: { trigger: h, start: 'top 75%', toggleActions: 'play none none reverse' },
    });
  }
});

// CTA
if (!reduced) {
  gsap.set('.cta-section h2, .cta-section p, .cta-section a', { opacity: 0, y: 25 });
  gsap.to('.cta-section h2, .cta-section p, .cta-section a', {
    opacity: 1, y: 0, duration: 0.8, stagger: 0.12, ease: 'expo.out',
    scrollTrigger: { trigger: '.cta-section', start: 'top 75%', toggleActions: 'play none none reverse' },
  });
}

// ─── Motion preference ────────────────────────────────────────────────────────
window.addEventListener('motion-preference', (e) => {
  if (e.detail.reduced) {
    gsap.globalTimeline.paused(true);
    ctx.clearRect(0, 0, velCanvas.width, velCanvas.height);
  } else {
    gsap.globalTimeline.paused(false);
  }
});

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Premium Velocity Experience — stealthisdesign</title>
  <link rel="stylesheet" href="style.css">
    <script type="importmap">{"imports":{"gsap":"/vendor/gsap/index.js","gsap/ScrollTrigger":"/vendor/gsap/ScrollTrigger.js","gsap/SplitText":"/vendor/gsap/SplitText.js","gsap/Flip":"/vendor/gsap/Flip.js","gsap/ScrambleTextPlugin":"/vendor/gsap/ScrambleTextPlugin.js","gsap/TextPlugin":"/vendor/gsap/TextPlugin.js","gsap/all":"/vendor/gsap/all.js","gsap/":"/vendor/gsap/","lenis":"/vendor/lenis/dist/lenis.mjs","three":"/vendor/three/build/three.module.js","three/addons/":"/vendor/three/examples/jsm/"}}</script>
  <style>html.lenis,
html.lenis body {
  height: auto;
}

.lenis:not(.lenis-autoToggle).lenis-stopped {
  overflow: clip;
}

.lenis [data-lenis-prevent],
.lenis [data-lenis-prevent-wheel],
.lenis [data-lenis-prevent-touch] {
  overscroll-behavior: contain;
}

.lenis.lenis-smooth iframe {
  pointer-events: none;
}

.lenis.lenis-autoToggle {
  transition-property: overflow;
  transition-duration: 1ms;
  transition-behavior: allow-discrete;
}</style>
</head>
<body>

  <!-- Velocity Canvas (fixed overlay) -->
  <canvas id="velocity-canvas" aria-hidden="true"></canvas>

  <!-- Three.js WebGL hero -->
  <canvas id="hero-canvas" aria-hidden="true"></canvas>

  <!-- Hero -->
  <section class="hero">
    <div class="hero-content">
      <div class="hero-tag">High Performance</div>
      <h1 class="gradient-text">Built for speed.<br>Designed to inspire.</h1>
      <p class="hero-desc">Scroll fast or scroll slow — this experience reacts to your velocity. Built with Three.js, Lenis, GSAP, and Canvas 2D in perfect sync.</p>
      <div class="speed-indicator" aria-live="polite">
        <span class="speed-label">Scroll Velocity</span>
        <div class="speed-bar-track">
          <div class="speed-bar-fill" id="speed-fill"></div>
        </div>
        <span class="speed-value" id="speed-value">0.0</span>
      </div>
    </div>
  </section>

  <!-- Depth Section -->
  <section class="depth-section">
    <div class="depth-cards">
      <div class="depth-card" style="--depth: 0.9; --card-hue: 195">
        <div class="dc-icon">◆</div>
        <h3>Velocity Tracking</h3>
        <p>Lenis exposes scroll velocity on every frame. The faster you scroll, the more dramatic the visual response.</p>
      </div>
      <div class="depth-card" style="--depth: 0.5; --card-hue: 270">
        <div class="dc-icon">▲</div>
        <h3>Canvas Speed Lines</h3>
        <p>Radial speed lines drawn on Canvas 2D scale with velocity magnitude — count, length, and opacity all react.</p>
      </div>
      <div class="depth-card" style="--depth: 0.7; --card-hue: 330">
        <div class="dc-icon">●</div>
        <h3>Three.js Hero</h3>
        <p>A WebGL scene runs in the hero background, rotating and reacting to scroll progress through GSAP.</p>
      </div>
    </div>
  </section>

  <!-- Velocity Stats -->
  <section class="stats-section">
    <div class="section-header">
      <span class="section-tag">Performance</span>
      <h2 class="gradient-text">Numbers in motion</h2>
    </div>
    <div class="stats-grid">
      <div class="stat-card" data-target="60" data-suffix=" fps">
        <div class="stat-value">0 fps</div>
        <div class="stat-label">Target Frame Rate</div>
      </div>
      <div class="stat-card" data-target="16.6" data-suffix=" ms">
        <div class="stat-value">0 ms</div>
        <div class="stat-label">Frame Budget</div>
      </div>
      <div class="stat-card" data-target="3" data-suffix="">
        <div class="stat-value">0</div>
        <div class="stat-label">Rendering Layers</div>
      </div>
      <div class="stat-card" data-target="0" data-suffix=" ms">
        <div class="stat-value">0 ms</div>
        <div class="stat-label">Input Lag</div>
      </div>
    </div>
  </section>

  <!-- Features -->
  <section class="features-section">
    <div class="section-header">
      <span class="section-tag">Techniques</span>
      <h2>What makes it tick</h2>
    </div>
    <div class="features-list">
      <div class="feature-item">
        <div class="feature-num">01</div>
        <div class="feature-text">
          <h3>Lenis Velocity API</h3>
          <p>Access real-time scroll velocity through Lenis's <code>scroll</code> event. Map the absolute value to visual intensity for reactive effects.</p>
        </div>
      </div>
      <div class="feature-item">
        <div class="feature-num">02</div>
        <div class="feature-text">
          <h3>Canvas 2D Compositing</h3>
          <p>A fixed Canvas layer sits above the page with <code>pointer-events: none</code>. Speed lines are cleared and redrawn each rAF tick.</p>
        </div>
      </div>
      <div class="feature-item">
        <div class="feature-num">03</div>
        <div class="feature-text">
          <h3>Three.js + ScrollTrigger</h3>
          <p>The WebGL hero canvas uses GSAP's ticker. Camera and mesh rotation are driven by scroll progress for seamless integration.</p>
        </div>
      </div>
      <div class="feature-item">
        <div class="feature-num">04</div>
        <div class="feature-text">
          <h3>CSS Hue Shift</h3>
          <p>Gradient text hue is updated each frame from a ScrollTrigger <code>onUpdate</code> callback — no repaints, just CSS variable changes.</p>
        </div>
      </div>
    </div>
  </section>

  <!-- CTA -->
  <section class="cta-section">
    <h2 class="gradient-text">Scroll to believe it.</h2>
    <p>Three rendering layers. Zero jank. One experience.</p>
    <a href="/" class="btn-primary">Back to Gallery</a>
  </section>

  <script type="module" src="script.js"></script>
</body>
</html>