Show HN: TTF-DOOM – A raycaster running inside TrueType font hinting(github.com)
38 pointsby 4RH1T3CT0R10 hours ago4 comments
  • tadfisher7 hours ago
    You are (or I suspect your LLM is) not correct about Doom using a raycasting engine. Wolfenstein fits that description, yes. Doom rather famously introduced BSP for level data and it draws sorted polygons front-to-back without ray-marching.
    • 4RH1T3CT0Ran hour ago
      technically yes, most constrained-platform ports (as I remember) do the same though (DOOMQL, the TI-84 version, the Excel one) since BSP is hard to fit into a limited VM. "DOOM-style" here is more about the genre than the rendering technique
      • bananaboyan hour ago
        It's not really a "DOOM-style raycaster" then, it's a Wolfenstein 3D-style raycaster.

        Pretty cool though!

  • kevin_thibedeau2 hours ago
    > TrueType MUL does (ab)/64, not ab

    This is how fixed-point arithmetic works. For multiplication of Q26.6 numbers you clear the squared scaling factors (2^6) by dividing/shifting one of them away.

  • emanuele-em9 hours ago
    Ok the MUL workaround got me. MUL does (ab)/64 so you have to DIV first to get a64, then MUL finally gives you a*b. And recursive FDEFs because there's no WHILE? All in 6.5KB? What kind of frame rate do you actually get out of this?
    • 4RH1T3CT0R8 hours ago
      Frame rate depends on the browser - Chrome gives around 30-60fps on my machine, but the bottleneck is actually Chrome deciding whether to re-run hinting at all (had to add axis jitter to force it). The TT bytecode itself executes fast, it's maybe a few thousand instructions per frame

        The recursive FDEF thing is the worst part honestly. Every while loop is a function that calls itself, and FreeType kills you at ~64 deep. So you're constantly juggling how many columns vs how many ray steps you can afford
  • tombert7 hours ago
    I tried playing the demo, and it was just green bars for me. The walls didn't scale up or shrink, it was just a bunch of solid static green bars.

    The enemies did scale up and shrink as I got closer, and the minimap worked.

    Tried with Brave on Linux, and Google Chrome on macOS.

    • 4RH1T3CT0R2 hours ago
      This is a FreeType issue - it uses auto-hinter by default on Linux and doesn't run the TT bytecode. No fix from CSS side unfortunately. Works on Windows/macOS where DirectWrite/CoreText run the bytecode
      • tombert2 hours ago
        It didn't work on macOS either.