5 ms·

Donut math - How donut.c works

237 points by dmuino 15y ago

swah 15y ago
In the 90's, I always wondered how this stuff worked.
- bigiain 15y ago
  And now it's 2011, I'm almost expecting some bright-young-thing to post up an alternative method, which involves offloading the 3d render and animation to the video card, painting that onto an invisible html5 canvas, then using JavaScript to paint ASCII characters over the top based on the average brightness/colour of regions of the hardware generated image...
  - JonnieCache 15y ago
    Isn't that basically how the various ASCII renderers for 3d games over the years have worked? Minus the html5 canvas obviously, although being as you can run the entire of quake in javascript/webgl, that can't be far off. Good old aalib. http://aa-project.sourceforge.net/ http://aa-project.sourceforge.net/
mrpollo 15y ago
I'm starting to grow even more jealous, this guy has some serious knowledge of his craft
a1k0n 15y ago
In a highly technical post like this I'm never sure how well I'm explaining it. I tried to keep things at the high school trig/algebra II level for this one. I've proofread it a billion times now but is there anything I can clarify?
- burgerbrain 15y ago
  Do you have any / know of any good documents about C obfuscation? I think that is the part that fascinates me most.
  - a1k0n 15y ago
    I don't know of any, but browsing through the archives of ioccc.org is probably an education in itself. That's where I got my own inspiration.
- xiaoqmanee 15y ago
  welcometo: http://www.fullmalls.com http://www.fullmalls.com The website wholesale for many kinds of fashion shoes, like the nike,jordan,prada,, also including the jeans,shirts,bags,hat and the decorations. All the products are free shipping, and the the price is competitive, and also can accept the paypal payment.,after the payment, can ship within short time. free shippingcompetitive priceany size availableaccept the paypal ===== http://www.fullmalls.com http://www.fullmalls.com ===== jordan shoes $32nike shox $32Christan Audigier bikini $23 Ed Hardy Bikini $23Smful short_t-shirt_woman $15ed hardy short_tank_woman $16Sandal $32christian loubo utin $80 Sunglass $15 COACH_Necklace $27handbag $33AF tank woman $17puma slipper woman $30 ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com =====
- rmccue 15y ago
  As a high school student, I can confirm you explained it well and I was able to follow it the entire way though. :)
- zkan 15y ago
  Congratulations. In my opinion, math is not easy to explain, but you did it very well. :)
- lachenmayer 15y ago
  I think I discovered a tiny problem in your 'relative proportions' formula picture. you have y' y - = - z' z' in the first line. The z' on the bottom right should be just a z, right? Other than that, this is perfectly clear, and I understood it even though I just came out of high school and haven't started college yet! Absolutely fantastic work! EDIT: Fraction format
  - a1k0n 15y ago
    Oops. Actually it's not a z' in the denominator in the second fraction, but a comma following the fraction bar. That's confusing; I have removed it. Thanks!
acangiano 15y ago
Would you really need to see a resume before hiring this guy?
- a1k0n 15y ago
  Anecdotally, yes.
  - dmuino 15y ago
    <resume> http://a1k0n.net/ </resume>
    - abjr 15y ago
      If you haven't done it yet, click the code on the bottom of that page :)
      - gabebw 15y ago
        A slightly unobfuscated version of that code: counter=0; pointer; main(){ while(counter<641){ for(pointer=0; "##K#8(38D-##C]L5870.X7\\M_b;90\\" "MC-M/NZGB6Q,I0VGB6a0FbN<VG.6Q\\bNb7^@`X=N@`XQaOVX:^]NX=:Z8PY]B`:>P" "NY8^$#SM):XA"[counter/6]-35>>counter++%6&1; pointer++); putchar(" _/\\\n,`)('<-"[pointer]); } }
  - buff-a 15y ago
    javascript, 3D, and mathematica. A very smart, yet very pragmatic fellow. Hired.
    - latentflip 15y ago
      Don't forget the ability to explain it well in writing!
identitycrisis 15y ago
As a fellow Yahoo good to still see people like andy *STILL around
- ajays 15y ago
  I agree! (another purple-bleeder here)
kqr2 15y ago
If you like deconstructing obfuscated c, then you may also enjoy Obfuscated C And Other Mysteries by Don Libes. In addition to coding advice, it looks at some of the top entries from the Obfuscated C Contest, 1984-1991. http://www.amazon.com/gp/product/0471578053/ http://www.amazon.com/gp/product/0471578053/ Also appears to be available as a reprint: http://www.cafepress.com/libes.43758522 http://www.cafepress.com/libes.43758522 Obfuscated C Contest website: http://www.ioccc.org/ http://www.ioccc.org/

237 points by dmuino 15y ago

swah 15y ago

In the 90's, I always wondered how this stuff worked.

bigiain 15y ago
And now it's 2011, I'm almost expecting some bright-young-thing to post up an alternative method, which involves offloading the 3d render and animation to the video card, painting that onto an invisible html5 canvas, then using JavaScript to paint ASCII characters over the top based on the average brightness/colour of regions of the hardware generated image...
- JonnieCache 15y ago
  Isn't that basically how the various ASCII renderers for 3d games over the years have worked? Minus the html5 canvas obviously, although being as you can run the entire of quake in javascript/webgl, that can't be far off. Good old aalib. http://aa-project.sourceforge.net/ http://aa-project.sourceforge.net/

mrpollo 15y ago

I'm starting to grow even more jealous, this guy has some serious knowledge of his craft

a1k0n 15y ago

In a highly technical post like this I'm never sure how well I'm explaining it. I tried to keep things at the high school trig/algebra II level for this one. I've proofread it a billion times now but is there anything I can clarify?

burgerbrain 15y ago
Do you have any / know of any good documents about C obfuscation? I think that is the part that fascinates me most.
- a1k0n 15y ago
  I don't know of any, but browsing through the archives of ioccc.org is probably an education in itself. That's where I got my own inspiration.
xiaoqmanee 15y ago
welcometo: http://www.fullmalls.com http://www.fullmalls.com The website wholesale for many kinds of fashion shoes, like the nike,jordan,prada,, also including the jeans,shirts,bags,hat and the decorations. All the products are free shipping, and the the price is competitive, and also can accept the paypal payment.,after the payment, can ship within short time. free shippingcompetitive priceany size availableaccept the paypal ===== http://www.fullmalls.com http://www.fullmalls.com ===== jordan shoes $32nike shox $32Christan Audigier bikini $23 Ed Hardy Bikini $23Smful short_t-shirt_woman $15ed hardy short_tank_woman $16Sandal $32christian loubo utin $80 Sunglass $15 COACH_Necklace $27handbag $33AF tank woman $17puma slipper woman $30 ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com ===== ===== http://www.fullmalls.com http://www.fullmalls.com =====
rmccue 15y ago
As a high school student, I can confirm you explained it well and I was able to follow it the entire way though. :)
zkan 15y ago
Congratulations. In my opinion, math is not easy to explain, but you did it very well. :)
lachenmayer 15y ago
I think I discovered a tiny problem in your 'relative proportions' formula picture. you have y' y - = - z' z' in the first line. The z' on the bottom right should be just a z, right? Other than that, this is perfectly clear, and I understood it even though I just came out of high school and haven't started college yet! Absolutely fantastic work! EDIT: Fraction format
- a1k0n 15y ago
  Oops. Actually it's not a z' in the denominator in the second fraction, but a comma following the fraction bar. That's confusing; I have removed it. Thanks!

acangiano 15y ago

Would you really need to see a resume before hiring this guy?

a1k0n 15y ago
Anecdotally, yes.
- dmuino 15y ago
  <resume> http://a1k0n.net/ </resume>
  - abjr 15y ago
    If you haven't done it yet, click the code on the bottom of that page :)
    - gabebw 15y ago
      A slightly unobfuscated version of that code: counter=0; pointer; main(){ while(counter<641){ for(pointer=0; "##K#8(38D-##C]L5870.X7\\M_b;90\\" "MC-M/NZGB6Q,I0VGB6a0FbN<VG.6Q\\bNb7^@`X=N@`XQaOVX:^]NX=:Z8PY]B`:>P" "NY8^$#SM):XA"[counter/6]-35>>counter++%6&1; pointer++); putchar(" _/\\\n,`)('<-"[pointer]); } }
- buff-a 15y ago
  javascript, 3D, and mathematica. A very smart, yet very pragmatic fellow. Hired.
  - latentflip 15y ago
    Don't forget the ability to explain it well in writing!

identitycrisis 15y ago

As a fellow Yahoo good to still see people like andy *STILL around

ajays 15y ago
I agree! (another purple-bleeder here)

kqr2 15y ago

If you like deconstructing obfuscated c, then you may also enjoy Obfuscated C And Other Mysteries by Don Libes. In addition to coding advice, it looks at some of the top entries from the Obfuscated C Contest, 1984-1991. http://www.amazon.com/gp/product/0471578053/ http://www.amazon.com/gp/product/0471578053/ Also appears to be available as a reprint: http://www.cafepress.com/libes.43758522 http://www.cafepress.com/libes.43758522 Obfuscated C Contest website: http://www.ioccc.org/ http://www.ioccc.org/