This repository contains the source code for our papers about real-time software rasterization of point clouds, which can be 10 to 100 times faster than GL_POINTS. This is possible because GL_POINTS is built upon the triangle-oriented rendering pipeline that is not optimal for pixel-sized points.
The basic idea is to spawn a compute shader that transforms points to screen space, encodes depth and color into a single 64 bit integer, and uses atomicMin to compute the closest point for each pixel. The color value is then extracted from the interleaved depth+color buffer and converted into a regular OpenGL texture for display.
The latest improvement also groups about 10k points into batches, and each compute workgroup(128 threads) renders a batch(10k points), i.e., each thread renders about 80 points. This allows several batch-level optimizations such as frustum culling, LOD rendering, and adaptive precision. Adaptive precision picks a sufficient coordinate precision (typically just 10 bit per axis) depending on the projected batch size, which boosts brute-force performance due to lower memory bandwidth requirements.
The main branch is a slightly more user friendly version that allows loading LAS files via drag&drop. Other branches contain snapshots of the code made after evaluations for specific paper submissions:
-
"Software Rasterization of 2 Billion Points in Real-Time"
In branch compute_rasterizer_2022
paper - video -
"Rendering Point Clouds with Compute Shaders and Vertex Order Optimization"
In branch compute_rasterizer_2021
- Renders up to one billion points in about 8 milliseconds (hence 2 billion points in real-time, 60fps) on an RTX 3090.
- You need to make sure not to load more than your GPU memory can handle. You'll need about 1.6GB for every 100 million points, plus 1GB or 2GB overhead.
- Drag & Drop a LAS or LAZ files into the window to load it. Only RGB attributes are displayed.
- Requires Windows and NVIDIA GPUs. Pull requests for AMD support are welcome.
- Clone the repository
- Compile build/ComputeRasterizer.sln with Visual Studio 2022.
- Run (ctrl + f5)
| Method | Location | |
|---|---|---|
| basic | ./modules/compute_loop_las | |
| prefetch | ./modules/compute_loop_las2 | fastest, each thread fetches 4 points at a time |
| hqs | ./modules/compute_loop_las_hqs | High-Quality Shading |
| LOD | ./modules/compute_loop_nodes | Support for the Potree LOD format |
| LOD hqs | ./modules/compute_loop_nodes_hqs |
@article{SCHUETZ-2022-PCC,
title = "Software Rasterization of 2 Billion Points in Real Time",
author = "Markus Sch\"{u}tz and Bernhard Kerbl and Michael Wimmer",
year = "2022",
month = jul,
journal = "Proc. ACM Comput. Graph. Interact. Tech.",
volume = "5",
pages = "1--16",
URL = "https://www.cg.tuwien.ac.at/research/publications/2022/SCHUETZ-2022-PCC/",
}
@article{SCHUETZ-2021-PCC,
title = "Rendering Point Clouds with Compute Shaders and Vertex Order Optimization",
author = "Markus Sch\"{u}tz and Bernhard Kerbl and Michael Wimmer",
year = "2021",
month = jul,
doi = "10.1111/cgf.14345",
journal = "Computer Graphics Forum",
number = "4",
volume = "40",
pages = "115--126",
keywords = "point-based rendering, compute shader, real-time rendering",
URL = "https://www.cg.tuwien.ac.at/research/publications/2021/SCHUETZ-2021-PCC/",
}
