How This Works: A Guide for Students

This webpage uses Three.js and WebXR to display a 3D model (A.glb) in a browser, with support for virtual reality (VR). Below is a simple explanation of how the code works and what each part does, so you can learn how to build your own 3D and VR projects!

• Three.js Library: Three.js is a JavaScript library that makes it easier to create and display 3D graphics in a web browser. It handles things like drawing objects, adding lights, and managing a virtual camera.
• Scene, Camera, Renderer: The scene is like a 3D world where objects live. The camera decides what you see, and the renderer draws the scene onto the screen. In this code, we set up a scene, a perspective camera (like a human eye), and a WebGL renderer to draw everything.
• Loading the 3D Model: We use the GLTFLoader to load a file called A.glb, which is a 3D model in the GLTF format. This file must be in the same folder as this webpage. Once loaded, the model is added to the scene so you can see it.
• Lighting: Without lights, the 3D model would be dark and invisible! We add an ambient light (soft, even lighting) and a directional light (like a spotlight) to make the model visible.
• Orbit Controls: On non-VR devices (like a laptop), you can click and drag the mouse to rotate around the model. This is done using OrbitControls, which lets you "orbit" the scene.
• WebXR for VR: WebXR is a web technology that lets browsers work with VR headsets. The XRButton adds an "Enter VR" button if your device supports VR. When clicked, it switches the view to your VR headset.
• Animation Loop: The animation loop runs continuously to update the scene and redraw it. This keeps the view interactive, letting you move the camera or enter VR mode smoothly.
• Why HTTPS or Localhost?: WebXR only works in secure environments (HTTPS websites or localhost on your computer). This is a browser security rule to protect users.

Try It Out! To experiment, replace A.glb with your own 3D model (in GLTF format). You can create models in tools like Blender and export them as .glb files. Check the browser console (F12 > Console) if the model doesn't load—it will show errors like a missing file. To learn more, visit the Three.js documentation or try tutorials on building 3D web apps!