9th.js/examples/tutorials/01-hello-world.html at master · syedrazaalino/9th.js · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>01 - Hello World: Basic Setup</title>
    <style>
        body {
            margin: 0;
            overflow: hidden;
            font-family: 'Courier New', monospace;
            background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
        }

        #canvas-container {
            width: 100vw;
            height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        #info {
            position: absolute;
            top: 20px;
            left: 20px;
            color: white;
            background: rgba(0, 0, 0, 0.7);
            padding: 20px;
            border-radius: 10px;
            max-width: 400px;
            line-height: 1.6;
        }

        h1 {
            margin: 0 0 15px 0;
            font-size: 24px;
            color: #4fc3f7;
        }

        .step {
            margin: 10px 0;
            padding: 10px;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 5px;
            border-left: 3px solid #4fc3f7;
        }

        code {
            background: rgba(0, 0, 0, 0.5);
            padding: 2px 6px;
            border-radius: 3px;
            color: #4fc3f7;
        }

        .highlight {
            color: #ffeb3b;
            font-weight: bold;
        }
    </style>
</head>
<body>
    <div id="info">
        <h1>🎯 Tutorial 01: Hello World</h1>
        <div class="step">
            <strong>Goal:</strong> Learn basic 3D scene setup
        </div>
        <div class="step">
            <strong>What you'll learn:</strong>
            <ul>
                <li>Creating a 3D scene</li>
                <li>Setting up a camera</li>
                <li>Initializing the renderer</li>
                <li>Adding objects to the scene</li>
                <li>The render loop</li>
            </ul>
        </div>
        <div class="step">
            <strong>Key Concepts:</strong>
            <ul>
                <li><code>Scene</code> - Container for all 3D objects</li>
                <li><code>Camera</code> - Defines what we see</li>
                <li><code>Renderer</code> - Draws the scene</li>
                <li><code>Mesh</code> - Basic 3D object</li>
            </ul>
        </div>
        <div class="step">
            <span class="highlight">✨ Watch the rotating cube!</span>
        </div>
    </div>

    <div id="canvas-container"></div>

    <!-- Three.js library -->
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/r128/three.min.js"></script>

    <script>
        /**
         * ==========================================
         * TUTORIAL 01: HELLO WORLD - BASIC SETUP
         * ==========================================
         *
         * This is your first 3D scene! Let's break down what we're doing:
         *
         * 1. SCENE: Think of this as a 3D world or container
         *    - Everything 3D goes inside the scene
         *    - Like a stage where objects perform
         *
         * 2. CAMERA: This is your "eye" in the 3D world
         *    - Defines the viewpoint and what you see
         *    - Like a camera or your eyes looking at objects
         *
         * 3. RENDERER: This draws everything to the screen
         *    - Converts 3D data to 2D pixels
         *    - Like a painter bringing the scene to life
         *
         * 4. MESH: A basic 3D object
         *    - Made of geometry (shape) + material (appearance)
         *    - Like a statue: shape + paint/color
         */

        // ==========================================
        // STEP 1: CREATE THE SCENE
        // ==========================================
        // The scene is your 3D world container. Everything you want to display
        // goes inside this scene.
        const scene = new THREE.Scene();

        // Optional: Set a background color for the scene
        // This creates a nice gradient effect when combined with CSS
        scene.background = new THREE.Color(0x1a1a2e);

        console.log('✅ Scene created successfully!');

        // ==========================================
        // STEP 2: CREATE THE CAMERA
        // ==========================================
        // The camera defines your perspective. There are different types,
        // but PerspectiveCamera is most common for 3D applications.
        //
        // Parameters:
        // - Field of View (FOV): How wide the camera sees (in degrees)
        // - Aspect Ratio: Width / Height of your screen
        // - Near Clipping Plane: Closest distance to render
        // - Far Clipping Plane: Farthest distance to render
        const camera = new THREE.PerspectiveCamera(
            75,                                    // FOV: 75 degrees (pretty wide)
            window.innerWidth / window.innerHeight, // Aspect ratio
            0.1,                                   // Near: 0.1 units
            1000                                   // Far: 1000 units
        );

        // Position the camera back a bit so we can see the cube
        camera.position.z = 5;

        console.log('✅ Camera positioned successfully!');

        // ==========================================
        // STEP 3: CREATE THE RENDERER
        // ==========================================
        // The renderer is what draws everything to your screen.
        // It takes the scene and camera and creates the final image.
        const renderer = new THREE.WebGLRenderer({ antialias: true });

        // Set the size of the rendering area
        renderer.setSize(window.innerWidth, window.innerHeight);

        // Add some pixel density handling for high-DPI displays
        renderer.setPixelRatio(window.devicePixelRatio);

        // Add the canvas to our container
        document.getElementById('canvas-container').appendChild(renderer.domElement);

        console.log('✅ Renderer initialized successfully!');

        // ==========================================
        // STEP 4: CREATE A MESH (3D OBJECT)
        // ==========================================
        // A mesh is made of two parts:
        // 1. GEOMETRY: The shape/structure (vertices, faces)
        // 2. MATERIAL: The appearance (color, texture, shine)

        // Create a box geometry (1x1x1 cube)
        const geometry = new THREE.BoxGeometry(1, 1, 1);

        // Create a material (how the object looks)
        const material = new THREE.MeshBasicMaterial({
            color: 0x00ff88,
            wireframe: false  // Set to true to see just the wireframe
        });

        // Create the mesh by combining geometry and material
        const cube = new THREE.Mesh(geometry, material);

        // Add the cube to our scene
        scene.add(cube);

        console.log('✅ Cube added to scene!');

        // ==========================================
        // STEP 5: CREATE THE RENDER LOOP
        // ==========================================
        // This is the animation loop that runs every frame.
        // Think of it as a movie projector that updates 60 times per second.

        function animate() {
            // Request the next animation frame
            // This creates a smooth 60fps animation loop
            requestAnimationFrame(animate);

            // ==========================================
            // STEP 6: ANIMATE THE CUBE
            // ==========================================
            // Rotate the cube a little bit on each frame
            cube.rotation.x += 0.01;  // Rotate around X-axis
            cube.rotation.y += 0.01;  // Rotate around Y-axis

            // Optional: You can also animate the scale
            // cube.scale.x = Math.sin(Date.now() * 0.001) * 0.5 + 1;
            // cube.scale.y = Math.sin(Date.now() * 0.001) * 0.5 + 1;
            // cube.scale.z = Math.sin(Date.now() * 0.001) * 0.5 + 1;

            // ==========================================
            // STEP 7: RENDER THE SCENE
            // ==========================================
            // Finally, render the scene from the camera's perspective
            renderer.render(scene, camera);
        }

        // ==========================================
        // STEP 8: HANDLE WINDOW RESIZE
        // ==========================================
        // Make sure the scene looks good when you resize the window
        window.addEventListener('resize', function() {
            // Update camera aspect ratio
            camera.aspect = window.innerWidth / window.innerHeight;
            camera.updateProjectionMatrix();

            // Update renderer size
            renderer.setSize(window.innerWidth, window.innerHeight);
        });

        // ==========================================
        // START THE ANIMATION!
        // ==========================================
        // Everything is set up, now start the animation loop!
        animate();

        // ==========================================
        // EXPERIMENT IDEAS:
        // ==========================================
        // 1. Try changing the cube color:
        //    material.color.setHex(0xff0000); // Red cube

        // 2. Try different shapes:
        //    const geometry = new THREE.SphereGeometry(1, 32, 32);
        //    const geometry = new THREE.ConeGeometry(1, 2, 32);

        // 3. Try wireframe mode:
        //    material.wireframe = true;

        // 4. Try different rotations:
        //    cube.rotation.z += 0.02;

        // 5. Try adding more cubes:
        //    const cube2 = new THREE.Mesh(geometry, new THREE.MeshBasicMaterial({color: 0xff0000}));
        //    cube2.position.x = 2;
        //    scene.add(cube2);

        console.log('🎉 Hello World setup complete! Check out Tutorial 02 for basic shapes!');
    </script>
</body>
</html>