[HN Gopher] SpaceSim
       ___________________________________________________________________
        
       SpaceSim
        
       Author : Luc
       Score  : 344 points
       Date   : 2025-01-03 17:05 UTC (1 days ago)
        
 (HTM) web link (pavelsevecek.github.io)
 (TXT) w3m dump (pavelsevecek.github.io)
        
       | yboris wrote:
       | Tangentially related: _Gravity Wars_ - a fun 2 player physics
       | artillery game where planets affect projectile path
       | 
       | https://github.com/whyboris/Gravity-Wars
        
         | tetris11 wrote:
         | Oh wow, I wish saw this in the list of projects when LOVE was
         | featured here the other day.
         | 
         | This looks super fun.
         | 
         | Edit: I'm loving the explosion-revenge last-ditch effort to
         | counterstrike when hit. Fantastic concept.
        
         | imiric wrote:
         | Moonshot[1] is another similar game, and a bit more polished.
         | It was abandoned, unfortunately, but it's fun for a few
         | minutes.
         | 
         | I just noticed there's Orbit Outlaws[2] from the same
         | developer, which builds on the same concept (for better or
         | worse), but is also abandoned.
         | 
         | [1]: https://store.steampowered.com/app/426930/Moonshot/
         | 
         | [2]: https://store.steampowered.com/app/1319100/Orbit_Outlaws/
        
         | cafeinux wrote:
         | > _Tangentially related_
         | 
         | I see what you did here.
        
       | NKosmatos wrote:
       | It would be fun if we could define planets with our own
       | materials, like bananas (influenced by xkcd), diamonds or
       | whatever other silly substance we like :-)
        
         | stoneman24 wrote:
         | Or chocolate (Terry Pratchett: Thief of time) IIRC
        
       | PointyFluff wrote:
       | Developing for a single platform in 2025 is like developing for a
       | single web-browser in 2005.
        
         | pavlov wrote:
         | Developing for a single platform in 2025 is like developing for
         | a single platform in 2005, if you don't care about mobile.
         | 
         | The desktop marketshare of the various platforms hasn't
         | fundamentally shifted since then. Mobile was all additive, and
         | Microsoft lost it. But Mac and Linux remain roughly where they
         | were.
        
           | ugh123 wrote:
           | This chart indicates lots of growth for OSx since at least
           | 2009 (as their data goes back to).
           | 
           | https://gs.statcounter.com/os-market-
           | share/desktop/worldwide...
        
             | briandear wrote:
             | Would be interesting if they took out enterprise and/or
             | computers were forced to use rather than chose to purchase.
        
           | ordu wrote:
           | I believe, that the GP comment is too dismissive, but it is
           | true. In 2005 when the dominance of IE started to dissolve it
           | was not the best move to develop for a single browser. Though
           | people still did it.
           | 
           | Today we see a rise of ARM on desktops, developing for x86
           | excludes Mac users, but the situation moves in a direction
           | when exclusive x86 software will exclude an assortment of
           | users of different OSes who chose to buy ARM desktop/laptop.
           | 
           | But I completely understand the choice made by the author, to
           | use vector extensions on two (or three? RISC-V?) processors
           | would be a much more additional work. The project is FOSS so
           | anyone can jump in and add support for ARM vector extensions.
           | Hopefully it will be easier then to write it from scratch,
           | because you can compare intermediate results bit to bit, and
           | catch mistakes red handed.
        
         | owenthejumper wrote:
         | Not everything is a VC funded thing. This is clearly a research
         | project at a university - notice the ff.cuni.cz links in the
         | images.
        
           | gray_-_wolf wrote:
           | It's mff.cuni.cz. ff.cuni.cz is faculty of philosophy, mff is
           | faculty of math and physics :)
        
         | rescbr wrote:
         | Paraphrasing somebody: Win32 is the most stable Linux API.
        
           | Koshkin wrote:
           | Unironically, true.
        
         | franga2000 wrote:
         | As one of your sibling comments points out: it works perfectly
         | on Wine.
        
       | greenavocado wrote:
       | Installer and game work perfectly on Intel Integrated Graphics on
       | Linux with Wine 9.22
        
         | pixelesque wrote:
         | Note that it does build natively for Linux (and other
         | platforms) from source, and the github page:
         | 
         | https://github.com/pavelsevecek/OpenSPH
         | 
         | includes an old Debian package you can install (although for
         | Debian 10, and doesn't work on recent Ubuntu/Mint installs
         | either)...
        
           | throwaway314155 wrote:
           | Certainly feels like a missed opportunity not to advertise
           | that somewhere official.
        
       | mturk wrote:
       | This is really impressive.
        
         | pixelpoet wrote:
         | I worked with the author at Corona Renderer; guy's a genius, no
         | sweat.
        
       | apetrov wrote:
       | Looks great, but GitHub metrics indicate that, unfortunately, the
       | project has stalled. The last commit was six months ago on master
       | and two months ago on develop.
       | 
       | source:
       | https://github.com/pavelsevecek/OpenSPH/graphs/contributors
        
         | apetrov wrote:
         | update: based on author's activity on youtube, he still works
         | on it
         | https://www.youtube.com/@pavelsevecek/videos?view=0&sort=dd&...
        
         | PontifexCipher wrote:
         | Two months without a commit could still be quite active and
         | useful software, especially for a personal project. Where would
         | you draw the line?
        
           | apetrov wrote:
           | Yes, I don't question the usefulness of the project by any
           | means. To be frank, I'm personally very interested in it--I
           | studied celestial mechanics at university many years ago and
           | am still curious about simulations.
           | 
           | The graph on the chart I shared suggests that the peak of
           | contributions was a couple of years ago, with occasional
           | changes since then. This doesn't make much sense to me, as
           | the rendering quality looks great (at least in the videos--
           | I'll try the software a bit later), and it's head and
           | shoulders above what the scientific community is currently
           | using.
        
             | risenshinetech wrote:
             | You can't imagine that someone working on something like
             | this would slow down as the work neared completion? Why
             | must a piece of software / code constantly be changing?
             | What's your specific concern? You're making a very strong
             | claim that the "project has stalled" without any real
             | evidence. Furthermore, the project "stalling" makes it
             | less... what, exactly?
        
               | apetrov wrote:
               | Yes, I can imagine multiple reasons why an author might
               | decide to change their pace for whatever reason. my
               | observation was that it changed.
               | 
               | Based on my experience (both personal and from
               | colleagues), when a project is not in active development,
               | the team starts losing knowledge of the codebase along
               | with its context. For example, something that was at your
               | fingertips while actively working on the project would be
               | much more difficult to recall after a year. The
               | difficulty of maintaining or extending the project grows
               | over time if it is not actively worked on.
               | 
               | 'Stalled' = contributions become less and less frequent.
               | 
               | If a project has stalled, there isn't much new happening.
               | For a simulation like this, the sky is the limit--you can
               | make it as accurate as possible (e.g., accounting for
               | light pressure - esp. significant around blackhole
               | acceleration disk, the Yarkovsky effect, etc.)
        
             | mturk wrote:
             | I don't think that it's fair to compare the rendering to
             | what is currently in use in the scientific community, for
             | two main reasons:
             | 
             | The first is that different types of rendering have
             | different uses; typically in scientific visualization this
             | is broken down into essentially "viz for self, viz for
             | peers, viz for others" and oftentimes the most well-used
             | rendering engines are targeted squarely at the first and
             | second categories. The visual language in those categories
             | is qualitatively different than that used for more "outward
             | facing" renderings.
             | 
             | The second reason is that I disagree with your assertion
             | about the quality of the visualization techniques in use
             | within science. There are some truly spectacular
             | visualization engines for cosmology and galaxy formation --
             | just to pick two examples off the top of my head, the work
             | done by Ralf Kaehler or that by Dylan Nelson. (There are
             | _many_ really good examples, however, and I feel guilty not
             | mentioning more.)
             | 
             | As I said in another, rather terse and unelaborated
             | comment, though, this is really, really impressive work. I
             | think it's important that in praising it, however, we don't
             | discount the work that's been done elsewhere. This need not
             | be zero-sum.
        
               | apetrov wrote:
               | I don't mean to discount any other work. I have already
               | disclaimed that I don't work in academia and rely on
               | second-hand feedback from my classmates (in Europe)--for
               | example, the Fortran implementation of Yoshida's method
               | from N years ago that nobody could modify, or the
               | pressure for publication. Building (or learning) a new
               | rendering engine would be a losing strategy in an
               | academic career, as it is a much more difficult path to
               | getting published. There are far fewer postdoc positions
               | than PhD positions, and rendering skills won't help in
               | this competition.
               | 
               | Regarding the work of Ralf Kaehler: I have seen his
               | renderings and looked through his articles, but to the
               | best of my knowledge, no source code is publicly
               | available. I don't consider it fair to count it as
               | something actively used in the field, beyond his lab and
               | affiliated projects.
               | 
               | Disclaimer: that doesn't mean that there are no others,
               | but their availability to researchers is limited to be
               | widely spread.
        
         | stackghost wrote:
         | I dunno, I have active hobby projects that go weeks to months
         | without commits. Sometimes you need to experiment with things
         | for a while to get a feel for whether or not it should be
         | committed. Sometimes you need to take a break.
         | 
         | The bullshit amounts of churn-for-the-sake-of-it in the
         | JavaScript ecosystem aren't normal.
        
           | apetrov wrote:
           | It depends on the complexity of the project. I assumed
           | something nontrivial, like this project. I outlined some
           | thoughts on the effects of consistent development and what
           | the project might become in a comment above (current state
           | vs. becoming a go-to visualization tool in the field for
           | years to come).
           | 
           | Regarding the JavaScript ecosystem--I never mentioned it.
           | Replacing one tool with another has nothing to do with the
           | evolution of a single project.
        
           | lucb1e wrote:
           | > hobby projects that go weeks to months without commits
           | 
           | Just months? :D Last week, a hobby project took down various
           | unrelated services on my server (like receiving email) by
           | causing disk space to suddenly fill up. The root cause is bad
           | handling of an expired third-party domain. I had last touched
           | that in 2012!
           | 
           | Or the grocery list software I use daily: its main activity
           | period is probably 2015 through 2018, with features/bugfixes
           | being added maybe once every 2-3 years nowadays. Back in
           | September that I added a small feature we now use on most
           | grocery trips, but since it gets daily use by the developer,
           | it's not like it's unsupported
           | 
           | One of my few projects that has regular users besides family
           | is a ~2013 rewrite of a 2011 file uploader. Sometimes there
           | is over a year between any change at all, but whenever
           | someone came along with a bug report I think the fix was
           | never more than a few days away. Come to think of it, it was
           | just today that a friend reported being happy that I still
           | provide it
           | 
           | Although stalled perhaps isn't inaccurate, I would feel that
           | it gives the wrong vibe if someone used that to described
           | these daily-used projects where the bug reporting method pops
           | a silent notification on my phone and I'm acting upon any. No
           | offense to u/apetrov, I get what they meant when reading
           | their subsequent replies elsewhere in the subthread
        
         | stevage wrote:
         | 2 months between commits seems fine for a hobby project. I
         | wouldn't call it dead for a couple of years.
        
       | lacoolj wrote:
       | I just did this install, then went to remove and it attempted to
       | remove `/usr/local/bin`
        
         | dylan604 wrote:
         | typing in 'rm' in any script I write scares the bejeebus out of
         | me. I tend to write 'echo rm' so I get a chance to review while
         | testing to catch this specific type of issue.
        
           | lucb1e wrote:
           | Can use -i to confirm deletions also, to not have to edit and
           | re-do the command. The downside is being asked for everything
           | individually rather than confirming one (big) list, so not
           | sure if this fits your use-case
        
             | dylan604 wrote:
             | the -i option doesn't really work well for scripts intended
             | to run unattended and headless, so no it doesn't fit the
             | use case.
             | 
             | now i'm waiting for the suggestions to use -rf
        
           | mmahemoff wrote:
           | Instead of deleting anything, my scripts usually mv files to
           | a timestamped folder under /tmp. In practical terms, it's
           | rarely a noticeable difference in performance or disk usage.
           | Also makes scripts easier to debug when you can inspect
           | transient artifacts.
        
             | dylan604 wrote:
             | I manage large video/audio assets, so disk usage is very
             | noticeable. I've done the mv to a designated trash folder
             | with another script that finds files in that folder older
             | than designated time to live and then -exec rm -f {} \;
             | type of stuff. Even typing that out still gives me pause.
             | Nobody ever needs a file with such urgency as just 24 hours
             | after it was deleted, but not in the designated time out
             | window.
        
             | yencabulator wrote:
             | My workstation machines take hourly(+at boot+on demand)
             | snapshots of the filesystem. Doing it on the system level
             | is a lot simpler than repeating the logic over and over,
             | and /tmp is often a different mount then where the files
             | first resided so moving things over there is a copy+delete.
        
           | mdaniel wrote:
           | In case you're interested, I have adopted a pattern that
           | works for me in bash _(I don 't use zsh so caveat shellator)_
           | N=${N:-}  # if you use (-u)       $N rm ./whatever
           | 
           | and then you can exercise the script via
           | N=echo ./something-dangerous
           | 
           | but without the N defined it will run it as expected. More
           | nuanced commands (e.g. rsync --delete --dry-run which will
           | provide a lot more detail about what it thinks it is going to
           | do) could be written as `rsync --delete ${N:+--dry-run}` type
           | deal
        
         | butz wrote:
         | Well, that's just one way to get "space" :)
        
         | ordu wrote:
         | Did it try it with `rm -r` or with `rmdir`? `rmdir` seems
         | perfectly ok for me, it will keep /usr/local/bin intact if
         | there left files.
        
       | tetris11 wrote:
       | Are there any easy examples one can just run once installed?
       | 
       | Or can anyone on HN give me any hints on a valid flow chart
        
       | andrepd wrote:
       | Cf. https://spaceengine.org/
        
       | DarkmSparks wrote:
       | very very cool, its also so rare these days to see the scientific
       | crowd bother building windows installers, now people whose only
       | skillset is using microsoft word and cheating in games can get a
       | glimpse of what modern compute is capable of, hopefully inspire
       | some of them to think beyond badly formatted text documents.
       | 
       | Although at this point they are more likely to call it science
       | fiction because they all know the earth is flat.
        
       ___________________________________________________________________
       (page generated 2025-01-04 23:01 UTC)