Show HN: A game where you build a GPU • Hacker News Board

Re: Show HN: A game where you build a GPU

#121

Post by sarvagyavaish » Sat, Apr 04, 2026, 10:24 PM UTC

Jaso1024 wrote: post #91

sarvagyavaish wrote: post #77

Earlier quoted context omitted.

Oh that's what the "copy circuit" button does. I have been trying to paste circuits from previous levels into subsequent ones and wondering what I was doing wrong

lol, mb; ill make that more clear (ill also give the ability to copy things cross level and intra-level)

Nw! This is an excellent game overall. I have always had a REALLY hard time understanding the electronics behind gates and this has been super helpful. I understood the physics behind NMOS and PMOS, and separately what logic tables represented and could be combines for higher order execution. The first few levels, constructing NANDs and NORs, has always been a puzzle - until today! Thank you <3

Re: Show HN: A game where you build a GPU

#122

Post by Jaso1024 » Sat, Apr 04, 2026, 10:24 PM UTC

jomoho wrote: post #118

first level is impossible to solve for me! Hint or showing solution did not work! Also adding multiple sources or ground behave differently than connecting to the same.

Next update has warnings about bus contention (multiple things into one node) when its an issue, and will have a proper show solution button.

For level 1.1 the solution is basically to take the ground and use that as a singular input to the source pin of an nmos transistor, let the input to the level be the gate pin of that same nmos transistor, and to let the drain (top) pin of that nmos transistor connect to the level's output

Re: Show HN: A game where you build a GPU

#123

Post by brcmthrowaway » Sat, Apr 04, 2026, 10:42 PM UTC

roadbuster wrote: post #40

I worked on deep sub-micron, full custom mixed-signal integrated circuits for more than a decade, and I can't pass the first level. > Wire an NMOS transistor so that when In is 1, the output is pulled to ground (0). When In is 0, the output should be unconnected (Z). Certainly: (a) The nMOS has 3 connections: its drain is only connected to the output (no +Vdd supply), it's source is tied to ground, it's gate is tied…

Did you switch to software?

Re: Show HN: A game where you build a GPU

#124

Post by mdtrooper » Sat, Apr 04, 2026, 11:00 PM UTC

It sounds great, it remembers to me:

- https://www.nand2tetris.org/

- https://nandgame.com/

Re: Show HN: A game where you build a GPU

#125

Post by varenc » Sat, Apr 04, 2026, 11:03 PM UTC

Jaso1024 wrote: post #49

roadbuster wrote: post #40

I worked on deep sub-micron, full custom mixed-signal integrated circuits for more than a decade, and I can't pass the first level. > Wire an NMOS transistor so that when In is 1, the output is pulled to ground (0). When In is 0, the output should be unconnected (Z). Certainly: (a) The nMOS has 3 connections: its drain is only connected to the output (no +Vdd supply), it's source is tied to ground, it's gate is tied…

lol, mb. As in understand it, its that the colors of the bg make it seem like its wires when its not, I'll change the color theme a bit to fix (plz correct me if my understanding is wrong)

consider a colorblind mode that uses patterns instead of colors for those of us that are color-challenged

Re: Show HN: A game where you build a GPU

#126

Post by hristov » Sat, Apr 04, 2026, 11:05 PM UTC

Ok you have put a lot of work in this and it looks impressive. But it needs a serious balance change. It is far too hard. Currently this may work as a brain teaser for people in the industry or people with computer engineering degrees, but it wont bring any fresh young minds into the industry. The fresh young minds will be scared off.

Teaching is challenging stuff. You have to step out of your current mindset and think with the mind of someone that sees this stuff for the first time. It is not easy to make things look easy and simple. Specifically, I think you need a lot more exploration about cmos logic, about how one side pulls the output up or the other side pulls the output down but they are never on at the same time, about how they effectively amplify the result so the output does not have to depend on the power of the input, etc. Perhaps you can try to have people design things in NMOS logic than in PMOS logic and then combine the two to make a CMOS design to see how they complement each other.

But I do not want to discourage you. This is a very promising start and you should continue if you have the time.

Also, the timed answers -- are you kidding me? The time is waaay too short. And you fail all if you fail a single answer. Oh what is 0xDE in decimal, all I have to do is multiply 16 by 13 and add 14 to that. In my head in 12 seconds. Also the time is not sufficient for filling out truth tables, especially with a laptop trackpad. I was able to pass the truth tables, but gave up on hexracing.

Ok and here are some more specific issues.

-The wires seem to snap in position in a way that they superimpose each other so it becomes very difficult to see what your circuit is doing.

- truth tables seem to be bugged. If you have more inputs than the gate whose truth table you are looking at, sometimes it will generate a fictitious truth table with extra inputs. Thus, some times i get a NOT truth table that has two inputs.

- the ground element should have its connection circle on the top, not the bottom. I realized that you can rotate by pressing R, but the site does not mention that anywhere.

Re: Show HN: A game where you build a GPU

#127

Post by Liebmann5 » Sat, Apr 04, 2026, 11:30 PM UTC

I have been looking for something like this for so longggg! THANK YOU

Re: Show HN: A game where you build a GPU

#128

Post by rg2004 » Sat, Apr 04, 2026, 11:40 PM UTC

I would have really liked to have a temporary node to test the outputs. Better than that, I would have liked to see the truth table update in real time without running the tests.

Re: Show HN: A game where you build a GPU

#129

Post by dcreater » Sat, Apr 04, 2026, 11:42 PM UTC

Jaso1024 wrote: post #49

roadbuster wrote: post #40

I worked on deep sub-micron, full custom mixed-signal integrated circuits for more than a decade, and I can't pass the first level. > Wire an NMOS transistor so that when In is 1, the output is pulled to ground (0). When In is 0, the output should be unconnected (Z). Certainly: (a) The nMOS has 3 connections: its drain is only connected to the output (no +Vdd supply), it's source is tied to ground, it's gate is tied…

lol, mb. As in understand it, its that the colors of the bg make it seem like its wires when its not, I'll change the color theme a bit to fix (plz correct me if my understanding is wrong)

the part that tripped me up is 0 showing in deep RED and I thought that meant I was doing something wrong. I came here, read this and realized I was actually right and then pressed the Run tests button and passed. This is a UX thing you'd want to address

Re: Show HN: A game where you build a GPU

#130

Post by dcreater » Sat, Apr 04, 2026, 11:44 PM UTC

Nice vibe coded project. There are a few UX holes i've encountered so far: No way to go to the next lesson if we dismiss the modal (have to go back to the tree and then click the next lesson)? more hints or step wise reveal if user gets stuck will be very helpful