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jcl

5,205 karma · joined February 8, 2008

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jcl··on The making of Dark Castle
An easter egg that I fondly recall finding: If you ran the game on December 25th, the suit of armor in the entryway is replaced with a Christmas tree.
jcl··on Pixar's senior scientist explains how math makes the movies and games we love
From 2013, which might be why the most recent movie referenced is Brave.

If you're interested in a slightly more concrete example of the math going into Pixar movies, here's a Numberphile interview with Tony DeRose from around the same time:

https://news.ycombinator.com/item?id=8610626

jcl··on What Works and Why: Opus Magnum
Fun fact revealed in a GDC talk: Even Zach Barth himself did not feel motivated to complete the final SpaceChem level. He just designed it to the point where it "looked solvable" and then turned his playtesters loose on it.

( https://archive.org/details/GDC2013Barth at 19:20)

jcl··on An iOS App in Assembly (2014)
True, if you're writing a typical app, it will probably be easiest for you if you write it in the same manner as most other people.

But if you are doing something very new or unusual, a sample project like this can be invaluable, since it shows the exact set of system calls needed for an app and roughly the minimal code. This is useful if, for example, you're trying to make a new language framework run on iOS (like Swift, Kotlin, or Rust), or if you're trying to answer questions like, "How much of an app's size is unavoidable?"

jcl··on Patent trolls are shaking us down for selling “rubies” in our game
FWIW, This w3.org web standard for per-fee-links (dated Aug 1999) describes a micropayment system that can be denominated in arbitrary currencies, giving "airline miles" as one possible example:

https://www.w3.org/TR/WD-Micropayment-Markup/#Appendix%207

jcl··on Wolfenstein's original rendering engine as 450 line shader with no external data
It's actually closer to the Wolfenstein rendering engine than one might expect... Like the original, it does a ray-march in the ground plane to find map objects:

https://github.com/id-Software/wolf3d/blob/0516778/WOLFSRC/W...

And, like the original, it separates the cases of wall blocks, door blocks, and sprites. It also expedites ceiling/floor drawing by just picking a flat color for the top and bottom halves of the screen:

https://github.com/id-Software/wolf3d/blob/0516778/WOLFSRC/W...

But it naturally differs from the original in that it is rendering per-pixel rather than per-column, so it does not need to accumulate a list of sprite intersections to draw in reverse order over the walls -- it can just stop raymarching when it encounters an opaque pixel:

https://github.com/id-Software/wolf3d/blob/0516778/WOLFSRC/W...

In a sense, the shader works like rewriting and optimizing the original renderer so that it renders to a screen of a single pixel, then running 147,456 instances of the renderer to fill the 512x288 pixel screen.

jcl··on Wolfenstein's original rendering engine as 450 line shader with no external data
If you like this one, you'll probably also enjoy the "DOOM E1M1" shader, which not only reproduces the DOOM graphics, but also the level audio in a separate shader (note: sound autoplays):

https://www.shadertoy.com/view/lsSXzD

jcl··on Why can’t women get pregnant without the menstrual cycle? (2016)
Perhaps it was this article -- where analysis of age-50+ members of a particular Amish community showed that lifespan of mothers increases linearly up to 14 children, and increases with later age at last birth:

https://www.ncbi.nlm.nih.gov/pubmed/16510865

(Interesting... it also shows a positive -- but lower/noisier -- effect for fathers as well, so there may be more at work than just stem cells.)

jcl··on MPEG-2 Patents Have Expired
On reading the title, I was kind of hoping that it meant that all DVD player creators would be free to stop imposing the artificial restrictions present on many DVDs, like region locks, "unskippable" tracks, etc. But it looks like the primary driver of those restrictions is actually the DVD Copy Control Association, which I'm guessing holds a different set of IP and legal agreements than MPEGLA does.
jcl··on Cancer ‘vaccine’ eliminates tumors in mice
If I'm understanding the article correctly, it actually can't be used as a strictly preventative measure. It relies on the fact that the subject already has a tumor and that the subject's immune system has made progress in targetting the tumor.
jcl··on Ask HN: Is big-endian dead?
Now that I think about it, most manual arithmetic would also be easier if we described numbers with the least-significant digits first. If you're doing sums in your head, you could just list out the answer's digits as you calculate them, rather than needing to remember the list of digits and reverse them at the end.
jcl··on Rents dropping significantly across the Seattle area after new construction
I think it's more than just wear-and-tear... There are a lot of legal protections that make it hard to displace existing renters. Presumably most of these unoccupied homes are owned as rainy day assets, to either be sold or occupied in an emergency, and renters would limit this ability.

(It's hard to find data on how prevalent this is... From one article, it looks like a Palo Alto realtor estimated in 2015 that about 20% of home sales were to Chinese investors, with about half of these leaving the house unoccupied: http://sanfrancisco.cbslocal.com/2015/04/28/realtors-printin... )

jcl··on Quantum Game with Photons
I also found the interference in the beam splitters surprising, although experimenting in the game let me work out enough of the logic to finish the levels.

I found an article on Wikipedia that, from the pictures, seems to be describe the process... I assume this is the simulated effect?

https://en.wikipedia.org/wiki/Hong%E2%80%93Ou%E2%80%93Mandel...

jcl··on Why Is Anime Obsessed With Power Lines?
I think anime's predilection for establishing shots may be due in part to its manga roots...

In "Understanding Comics", Scott McCloud analyzed the transitions made between panels in various works, and he found that sequences of transitions between different views of an environment (what he called "aspect-to-aspect") were common in manga but were nearly absent in American or European comics. I believe he attributed this to the fact that manga typically has higher page counts than other comics, allowing the authors to invest more in setting up scenes.

jcl··on I gave Amazon a key to my house and regretted it
As far as security goes, a problem with "airlocks" is similar to a problem with attached garages: It's easier to get into them than directly into the house, and once you are in them, they can provide cover for a more concerted effort to get into the house. An Amazon-Key-like system may mitigate the risk, of course, assuming that the users of the app are properly vetted and that attackers are deterred by cameras.
jcl··on Fast desktop-scale extrusion 3D printing
FWIW, some UPS store locations offer 3D printing (although it seemed pretty expensive):

https://www.theupsstore.com/print/3d-printing

jcl··on Dither stabilisation
From the first post of the forum thread:

"My first computer was a Mac Plus. I've always had a nostalgia-softened spot in my heart for 1-bit graphics. I'd like to capture the detailed black & white look of old Mac games in a realtime 1st person game."

jcl··on Chuck Moore, Extreme Programmer
Per another comment, he's scheduled to be at an upcoming Forth meeting: https://www.meetup.com/SV-FIG/events/243613446/
jcl··on TerrariaClone – An incomprehensible hellscape of spaghetti code
Given the relative size of the function and typical memory, I suspect that the issue the author ran into was actually the JVM's 64KB limit on the bytecode size of a compiled function.

https://stackoverflow.com/questions/17422480/maximum-size-of...

jcl··on TerrariaClone – An incomprehensible hellscape of spaghetti code
Per the description on https://github.com/csnxs/Terraria/ , this isn't the Terraria source code -- it's a decompilation of the binary.
jcl··on Japanese Vending Machines at Night Juxtaposed with a Wintry Hokkaido Landscape
Could be Mount Yōtei, a Hokkaido mountain known for its resemblance to Mount Fuji:

https://en.wikipedia.org/wiki/Mount_Y%C5%8Dtei

jcl··on GNU Taler
"Add" itself is acceptable: "the desired currency must be added to the wallet's balance"
jcl··on A better way to make holograms
Reminds me a bit of the "caustic design" papers in recent SIGGRAPHs in that they're both optimizing a lens's shape so that it produces a particular output lightfield -- although the hologram needs to incorporate diffraction and produce a much more constrained lightfield.

(Caustic video: https://www.youtube.com/watch?v=R00IvqcI9jU&feature=youtu.be... )

jcl··on Here be dragons: the same 3D scene implemented with 10 different 3D APIs
The OpenGL version is using parallax mapping, where the pixels of the flat plane are rendered by ray-marching into a depth map:

https://github.com/kosua20/GL_Template/blob/3de4e116cdd24df3...

The cycles version, on the other hand, is actually using the depth map to displace a high-res mesh -- a more general technique that should yield results as good or better than parallax mapping. I'd chalk up any perceived differences to lighting and material parameters.

jcl··on MS Paint is here to stay
It's a conflation of two meanings of "clip": "to cut" or "to hold together". I'd always assumed that the software "clipboard" derived not from the common "board with a clip" but from a "board for clippings", as might have been used in a design firm in the days when cut, copy, and paste were done with an X-acto knife, a Xerox machine, and glue:

https://en.wikipedia.org/wiki/Paste_up

I haven't been able to find evidence of this alternate meaning for "clipboard", though, as modern use has rendered it un-Googleable. The best I've been able to find is that its use in computing probably started somewhere between Xerox PARC and the Apple Lisa:

http://www.liquidinformation.org/onxeaplaprog.html

I find it fascinating, though, that this word has stuck, propagated essentially by word-of-mouth -- like the contents of the clipboard itself, the word is generally not shown in user interfaces. "Scrapbook", the name of the clipboard management utility in the original Macintosh OS, would have made a lot more sense semantically.

jcl··on Algorithm generates practical paper-folding patterns to produce any 3D structure
A video of one of the authors folding a bunny model like the one in the article:

https://www.youtube.com/watch?v=GAnW-KU2yn4

jcl··on Open source deep learning models that programmers can download and run first try
Could you clarify? Several of the examples are Python projects (with and without Tensorflow), and others are apps consuming models that probably came from Tensorflow.
jcl··on C.S. Lewis's Greatest Fiction: Telling Kids They’d Like Turkish Delight (2015)
Heh... I knew this looked familiar. Per the note at the end of the article, it should probably be tagged "(2015)". Previous discussion under a slightly different title:

https://news.ycombinator.com/item?id=10686217

jcl··on Tectonic: a modernized, self-contained TeX/LaTeX engine
It's a pity they didn't go with "TeXtonic"... The canonical way to pronounce "TeX" is roughly "tech", since the "X" is supposed to be a Greek chi.

https://en.wikipedia.org/wiki/TeX#Pronunciation_and_spelling

(Of course, "textonic" is also the name of another open source project...)

jcl··on New Surface Pro
Heh... the current MacBook Pros only have USB-C ports, so MacBook users now similarly need display adapters until USB-C becomes common.
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