Skip to content
HomeVideosBooksBlogs
AllTop postsTopics
Podcasts
HistoryListsWatch laterLiked videosFollowing

The videos, books, blogs and podcasts Hacker News keeps recommending, all in one place.

VideosBooksBlogsPodcastsAboutPrivacySettings

Data from Hacker News, HackerTube, HackerBooks, HackerBlogs and Open Library. Credits · Not affiliated with Y Combinator.

HomeVideosBooksBlogsPodcasts
Ctrl K
    E

    Eric Lengyel

    terathon.com · Personal blog · on HN since 2013

    Eric Lengyel, a game engine developer and author of the Slug font renderer, writes on GPU text rendering, geometric algebra, and game development.

    Visit blogRSSHN submissions
    ProgrammingMathGames
    What HN says

    HN links it for the Slug algorithm's move to the public domain, the geometric algebra critique, and his game and engine posts, including Radical Pie.

    Stats for nerds
    38HN people shared it
    23linked in comments
    680story points
    Aug 2026last shared
    2015people per year2026

    Top posts on HN

    1. 1
      Poor Foundations in Geometric Algebra
      2 people · 229 points · first shared 2024 · 116 comments on HN
    2. 2
      Projective Geometric Algebra Done Right
      6 people · 140 points · first shared 2020 · 25 comments on HN
    3. 3
      So you want to write a technical book
      3 people · 136 points · first shared 2021 · 28 comments on HN
    4. 4
      A Mathematical Keyboard Layout (2018)
      1 person · 76 points · first shared 2021 · 50 comments on HN
    5. 5
      C4 game engine drops Linux support citing frustrations with desktop Linux
      1 person · 44 points · first shared 2015 · 84 comments on HN
    6. 6
      GPU-Friendly Font Rendering Directly from Glyph Outlines [pdf]
      2 people · 20 points · first shared 2017 · 1 comments on HN
    7. 7
      The Transwedge Product
      1 person · 11 points · first shared 2025 · 4 comments on HN
    8. 8
      The Return of Forgotten Math in Computer Graphics [pdf] (2012)
      1 person · 5 points · first shared 2025 · 1 comments on HN
    9. 9
      Geometric Algebra Books
      1 person · 3 points · first shared 2025 · Discussion on HN
    10. 10
      The Development of Radical Pie
      2 people · 2 points · first shared 2025 · Discussion on HN

    What HN people wrote when they linked it

    • layoutIfNeededJan 2020

      What you wrote has nothing to do with Eric's geometric antiproduct.

      Eric calls the dual vectors in a geometric algebra (or Grassmann algebra as he calls it) antivectors. See his presentation from GDC2012 around the middle:

      >Instead of saying (n−1)-vector, we call these “antivectors”

      http://www.terathon.com/gdc12_lengyel.pdf (also: https://youtu.be/WZApQkDBr5o?t=1673)

      So e.g. in 3D bivectors would be antivectors, in 4D trivectors would be antivectors, etc. He also calls what's usually referred to as pseudoscalars antiscalars - that is, n-vectors in an n-dimensional geometric algebra.

      The geometric antiproduct introduced in this article has a similar dual relationship with the geometric product: the geometric antiproduct acts on vectors the same way as the geometric product acts on antivectors. Around the end of the article he even writes that the whole algebraic structure is invariant under dualization (or "antization" :D ): you can map scalars to antiscalars, vectors to antivectors, etc. and the geometric product will be mapped to the geometric antiproduct, etc.

    • ivan_ahFeb 2020

      Thanks for sharing this blog post and the cheat sheet http://terathon.com/pga_lengyel.pdf

      I agree the representation chosen in the SIGGRAPH lecture and the associated docs seems somewhat unnatural and counter-intuitive (why are points being represented as trivectors?).

      Have you reached out to C. Gunn or S. De Keninck to ask what they think about the representation you propose in that blog post and the geometric product ⟑ and antiproduct ⟇ ? If the representations are equivalent and one is closer to concepts people already understand (e.g. points being (x,y,z,w), with w=1), then maybe adopting the simpler representation would lead to wider adoption of the ideas.

      Alternatively, maybe they will point out some other reasons why points-as-trivectors representation is preferable.

    • jevgeniJan 2015

      I like how you gloss over the "needed libraries".

      But seriously, let's take a quick look (here)[http://www.terathon.com/architecture.php] and think, what might be a clear pain point in Linux, even if the "needed libraries" worked perfectly with all the hardware and all distros and the blobs were perfect.

      Did I hear someone say "Linux sound support"? Yes, that is a correct answer. Sound in Linux is a know clusterfuck.

      What else might be not as trivial? Did someone say support for multiple graphic cards? Yes, even with OpenGL it might be an issue.

      Not to mention all the GUI tools.

      So yeah, those all things obviously would never have any less than functioning dependencies on Linux...

    • djmipsApr 2022

      Pretty good overview of what you asked about - https://medium.com/@evanwallace/easy-scalable-text-rendering-on-the-gpu-c3f4d782c5ac

      Other links
      https://developer.nvidia.com/gpugems/gpugems3/part-iv-image-effects/chapter-25-rendering-vector-art-gpu
      https://jcgt.org/published/0006/02/02/
      Also (https://terathon.com/i3d2018_lengyel.pdf) Which was developed into a product IIRC.

      Another GPU text renderer
      https://github.com/hypernewbie/VEFontCache

      There's been other development and some posts on Hacker News about rendering fonts on the GPU

    • anuramatJun 2026

      you might want to read this post by a GA researcher: https://terathon.com/blog/poor-foundations-ga.html

      especially the part about duals -- made me feel like I was going crazy when I was trying to figure out degenerate metrics: every source deals with it in a slightly different (often sloppy) way; you're sure it all must be possible to resolve and get something beautiful and consistent, but not while you're trying to apply it to a specific problem you need to solve

    • elengyelMay 2025

      I don't think you're missing anything. One of the goals of this article is to demonstrate how geometric algebra is really just another part of exterior algebra anyway. However, performing transformations in spacetime with the geometric product might make some things easier to understand, but I'm not making any strong claims about that. This article contains a small glimpse of what I'm talking about: https://terathon.com/blog/relativistic-quaternions.html

    Related

    Aras Pranckevičiusaras-p.info79 people

    I accidentally Blender VSE

    Aras Pranckevičius
    Personal · last shared 2026
    Fabien Sanglardfabiensanglard.net525 people

    The Polygons of Another World

    Fabien Sanglard
    Personal · last shared 2026
    Andre Weissflogfloooh.github.io100 people

    Tiny Emus: 8-Bit emulators

    Andre Weissflog
    Personal · last shared 2026
    Evan Wallacemedium.com/@evanwallace17 people

    Easy Scalable Text Rendering on the GPU

    Evan Wallace
    Personal · last shared 2026
    Bitsquid Blogbitsquid.blogspot.com25 people

    Allocation Adventures: The Buddy Allocator

    Bitsquid Blog
    Company · last shared 2025
    Jeremy Ongjeremyong.com22 people

    Basic skeletal animation with geometric algebra

    Jeremy Ong
    Personal · last shared 2025
    Charles Bloomcbloomrants.blogspot.com65 people

    Did I ever mention that I fucking hate the fucking web

    Charles Bloom
    Personal · last shared 2026
    Bertrand Meyerbertrandmeyer.com47 people

    Introduction to the Theory of Programming Languages (1991)

    Bertrand Meyer
    Personal · last shared 2026