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Comment by tertet | Hacker News Reader

It would not be that hard to write a 3D physics engine for a TI-89 calculator (Assuming you already know how to write a 3D physics engine, which I do). Problem is, it would be useless since it will probably take tens of seconds (if not more) to calculate each frame.

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I would not be so sure. It really all depends on how much physics you want your "physics engine" to have. Rag-dolls? Not likely. Quake 1? Sure, you could do physics to that extent on an 89. The 89's are more powerful than you may suspect, unlike the 84 (seen in the article), they have Motorola 68k's.

Here is an idea of what you can do with a 84's Zilog z80 (warning: long animated gif): http://benryves.com/images/nostromo/bsp/2010.11.28/Walkthrou...

(corresponding blog entry: http://benryves.com/journal/3739423)

You can get a lot more out of an M68k. (Actually, to be fair, the M68k calculators' larger screen size works against them, but if you are willing to sacrifice graphics you can easily surpass that demo.)

>>http://benryves.com/images/nostromo/bsp/2010.11.28/Walkthrou....

Not bad but it is not a 3D Physics engine. Just a renderer. Not the same thing. Still pretty impressive.

Certainly, I didn't mean to imply it is, just use it as a benchmark against which you can get an idea about what the 84 is actually capable of (the Portal thing isn't really a great demonstration of that).

(It is not in fact even a 3d engine, but rather a vector BSP 2.5D one that is technically similar to Doom. To the extent with Doom has physics (pretty much only momentum (seen prominently in how explosion knock back effects entities) and gravity, so not really) that demo kind of has physics. Actually I don't think he actually does momentum, and his gravity is primitive. He's pushing the calculator pretty hard, I'm not sure how much more you could add, but the 89 can do much better.)

Basically I think you could get something close to this on an 89 (with dramatically worse graphics/graphical abilities): https://github.com/id-Software/Quake/blob/master/QW/client/p...

I remember playing a lot with my old TI-83. One of the most impressive games was DOOM: http://www.ticalc.org/archives/files/fileinfo/238/23843.html Best video I can find: https://www.youtube.com/watch?v=TuupoxmeQ6U

Unfortunately I never had a TI-89. Would've been awesome if I had one back in the day, and then test these games: http://www.ticalc.org/archives/files/fileinfo/405/40593.html and http://www.ticalc.org/archives/files/fileinfo/323/32318.html

Ah yeah, good stuff. I was always partial to Gemini and Wolf on the 83+ (http://www.ticalc.org/archives/files/fileinfo/247/24742.html, http://www.ticalc.org/archives/files/fileinfo/277/27767.html). Wolf even had an on-calculator level editor!

Gemini blew the socks off of all my middle school friends, but I'm embarrassed by the amount of time I spent on Galaxian in math class. Maybe one of these days, I'll dig out my 83+ and complete the no laser, no death run that I was always aiming for, just for old time's sake.

In hindsight, I wish I had spent that time learning Z80 instead...

I always find it funny that someone actually ported Fruit Ninja. http://tiwizard.com/downloads/fruit-ninja/

The controls are pretty clever too.

That's the thing, though. I'd be awestruck to see a Portal 3D physics-like thing on the 89 and be playable, because I'd have no idea how the person pulled it off and as I said above it'd be mindblowing. If you're familiar with physics engines, perhaps you're familiar with how the GBA works at the hardware level and how a game for it is typically made? Super Monkey Ball Jr. is an example of a game that blew me away and I'm still not really sure how they pulled it off.

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