Spark - Matrix Effect with 3D Gaussian Splatting

This project demonstrates how to use the Spark library to create a "Matrix" style visual effect on a 3D Gaussian Splatting scene.

The demo loads a scene (greyscale-bedroom.spz) and dynamically applies a fractal shader using Spark's dyno system, modifying the color and position of the splats in real-time.

How the Effect Works

The core of the effect lies in a custom shader injected into the Spark rendering pipeline:

1. Generative Fractal: A GLSL fractal function creates geometric patterns based on coordinates and time.
2. Color Manipulation: The shader darkens the original scene and highlights specific areas with a characteristic neon green hue, modulated by the fractal value.
3. Geometric Deformation: Splats are displaced along the Y-axis following a sinusoidal and noise pattern, simulating digital "rain" or distortion.
4. Dyno System: Spark allows writing these shaders in JavaScript/TypeScript via its dyno API, which compiles to optimized GLSL.

About the Spark Library

@sparkjsdev/spark (v0.1.10) is an advanced 3D Gaussian Splatting renderer designed to integrate seamlessly with Three.js.

Key Features:

• High Performance: Uses WebAssembly (Rust) for intensive splat sorting and processing operations.
• Optimized Format: Native support for .spz files, an efficient compressed format for Gaussian Splats.
• Dyno System: A powerful programmable shader system that allows dynamic modification of splats (position, scale, color, rotation) without re-uploading geometry to the GPU.
• Three.js Integration: Works as just another object within the Three.js scene, allowing mixing of splats with traditional meshes, lights, and cameras.

Installation and Usage

To run this project locally:

1. Install dependencies:

   npm install

2. Start the development server:

   npm run dev

3. Open your browser at http://localhost:8080.

Project Structure

• /splat-matrix/main.js: Main scene logic and dyno shader definition.
• /assets/: Contains locally downloaded model and splat files (.spz).
• /src/: Source code of the Spark library.