Stratum - Point Cloud Engine

Stratum is a C++ rendering engine designed to visualize massive point cloud datasets in real-time. I built this over the winter'26 break to dive deeper into low-level graphics programming, memory management, and the OpenGL pipeline.

The goal was simple: take raw coordinate data (x, y, z) and render it at 60 FPS without crashing the system, even with millions of points.

demo.mp4

Key Features

• Real-time Rendering: Handles 10,000,000+ points smoothly using Modern OpenGL (Core Profile).
• Level of Detail (LOD): Implemented a custom grid-based spatial partitioning system. It culls chunks that are too far away and reduces point density for distant objects to save performance.
• Async Asset Loading: Uses std::future and worker threads to load data in the background, so the window opens instantly and doesn't freeze while parsing files.
• Interactive UI: Integrated Dear ImGui to control shader parameters like height map colors and point size on the fly.
• Custom Shaders: Wrote GLSL vertex and fragment shaders to create a dynamic height-based heatmap (Blue -> Green -> White).

Technical Implementation

1. Multithreading

One of the big issues I ran into early on was that parsing a large text file blocks the main thread. I refactored the DataLoader to use smart pointers (std::unique_ptr) and std::async. The data is loaded in a seperate thread, and ownership is transferred to the main renderer only when its ready. This keeps the application responsive during the heavy I/O operations.

2. Optimization (LOD)

To handle the scale, I split the terrain into a 4x4 grid of "Chunks". Instead of swapping meshes, I used a statistical trick: I shuffle the points inside the buffers. This allows me to simply draw less points (e.g. the first 10% of the buffer) when the camera is far away, and it looks like a uniform reduction in density rather than just cutting off the geometry.

Controls

• Left Click + Drag: Rotate Camera (Orbit)
• Scroll: Zoom In/Out
• ImGui Panel:
  • Adjust Sea Level (Min Height) and Snow Level (Max Height) to change the gradient.
  • Change background color and point size.

Build Instructions

This project uses CMake. You need a C++17 compliant compiler.

mkdir build
cd build
cmake ..
cmake --build .