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Show HN: SpaceX Dragon simulator docking autopilot in Clojure

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Re: Show HN: SpaceX Dragon simulator docking autopilot in Clojure

#6

Post by VLM »

I have a question about control flow of the overall system. Note that I haven't actually run this or debugged it. Or frankly, thought about it for more than a minute or two. Its more of an architectural question.

So in dragon.clj there's a case statement to execute commands in the translate function such that the command to go down or left in an abstract calculated sense is implemented as hitting a virtual down or left keyboard key.

What happens if you have to go down AND left?

I was just thinking why not pass a Clojure list to the translate function and when list contains a down it hits the virtual s key AND if the list contains a left command it hits a virtual a key, then you could wiggle "down-left" at the same time.

I mean, obviously it works and sometimes architectural decisions have no technical reason and are arbitrary, which would be perfectly OK. I was just idly curious.

Clojure is cool, like programmer catnip, so I had to look at it.

Re: Show HN: SpaceX Dragon simulator docking autopilot in Clojure

#7

Post by danpetrov »

VLM wrote: post #6

I have a question about control flow of the overall system. Note that I haven't actually run this or debugged it. Or frankly, thought about it for more than a minute or two. Its more of an architectural question. So in dragon.clj there's a case statement to execute commands in the translate function such that the command to go down or left in an abstract calculated sense is implemented as hitting a virtual down or le…

Heh, never thought about it that way! But good question. Yes, it can translate on 2 axes at the same time, since the control loops for each axis run in separate threads, so there is no control locking. The same is with rotation - it can e.g. pitch, roll and yaw at the same time.

Re: Show HN: SpaceX Dragon simulator docking autopilot in Clojure

#8

Post by Eduardo3rd »

GistNoesis wrote: post #3

https://www.reddit.com/r/spacex/comments/gigmfh/spacex_iss_d... does it in one line but it's kind of cheating.

browser console is a pretty under rated feature. I wish it was used more extensively to teach people how to code. so many cool little hacks you can do on public web pages that cement new concepts quickly.
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