Building an Interactive 3D Multiplane Engine

Transform static 2D layers into a dynamic, interactive 3D environment. This project demonstrates how to use Three.js to create a multiplane camera effect, similar to traditional animation techniques used by Disney, but with a modern web twist.

The engine features a custom-built parallax system that reacts to mouse movement, a seamless transition between 3D perspective and 2D "stacked" views using GSAP animations, and a high-contrast "Blue Screen" interface with yellow technical outlines for a distinct "production-suite" aesthetic.

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1. The Core Engine

The core of this application is driven by Three.js, a high-level JavaScript library that acts as a wrapper around WebGL.

• Scene Graph Management: The engine maintains a THREE.Scene where it manages 10 distinct PlaneGeometry objects (layers).
• Animation State Controller: It uses GSAP (GreenSock Animation Platform) for its state transitions. While Three.js handles the rendering, GSAP acts as the "brain" for movement logic, calculating the interpolation between the "Stacked" (2D) and "Exploded" (3D) positions.
• The Render Loop: The animate() function serves as the heartbeat, constantly updating positions and firing the renderer.render() command to refresh the screen.

2. Rendering Technology

The project utilizes Hardware-Accelerated WebGL via a WebGLRenderer. Unlike CSS-based 3D, this taps directly into the user's GPU (Graphics Processing Unit).

• Texture Mapping: Each layer is a MeshBasicMaterial with a TextureLoader mapping a PNG file. It uses alphaTest and transparent: true to handle complex transparency within the image files.
• Alpha Blending and Render Order: A crucial technical detail is the renderOrder and depthTest. When layers are stacked (Z=0), the engine must manually define which layer is on top to avoid "Z-fighting" (where the GPU doesn't know which pixel to draw first).
• Edge Rendering: It uses EdgesGeometry to draw yellow wireframes around each plane, helping the user perceive the spatial boundaries of each art layer.

3. Mathematical Tools

The "Parallax" effect is achieved through Normalized Device Coordinates (NDC) and Linear Interpolation.

• Coordinate Normalization: The mouse position is mapped from pixels to a range of -1 to +1:

• Coefficient-Based Offsets: Each layer is assigned a factor based on its index: (layerCount - index) *0.35. Layers further back in the stack have a higher factor, causing them to move "faster" or "further" relative to the mouse, creating the illusion of depth.
• Smoothing (Easing): The code uses a simple lerp-style smoothing formula:plane.position.x += (targetX - plane.position.x) * 0.05;This ensures the movement isn't robotic; it has a slight "weight" or delay as it follows the mouse.

4. Front-End Environment

The environment is built as a Modern ES Module (ESM) web application.

• Import Maps: It uses a <script type="importmap"> to resolve dependencies. This is a modern browser feature that allows you to use import statements for external CDNs (like Skypack and Unpkg) without a build tool like Webpack or Vite.
• Responsive Viewport: The environment listens for the resize event to update the camera.aspect ratio and renderer.setSize, ensuring the 3D scene doesn't stretch on mobile or ultra-wide monitors.
• UI/UX Layer: A standard HTML/CSS overlay is used for the control panel. It uses backdrop-filter: blur(5px) for a modern "glassmorphism" look, while pointer-events: auto ensures the buttons remain clickable over the 3D canvas.