Embassy of Time

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About Embassy of Time

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  1. As the dust settles...

    Holy.... mother.... of.... god.... Well, that was a learning experience. The kitten orphanage is on hold for now. After a few weeks, I was handed two feral cats and their four kittens to care for. It did not go well. They basically destroyed my home office in disgusting ways (the kittens were innocent, their two mothers did the destruction), and when I asked the people I volunteered for to take them back, they lambasted me for being a liar and worse, because I had offered to take in cats, so I had to take care of those, and now shut up. It escalated and they retaliated by taking all cats back and blacklisting me. I would say "unprofessional", but in their defense, they never claimed to be professional. It became clear to me, too late, that they had nooo idea what they were doing, and were just winging it. And as a side effect, the last two weeks have involved me trying to get rid of fleas, which EVERY SINGLE CAT had when they handed them over to me. I had nightmares about fleas... and then the nightmares came true. Literally, I remember a dream about standing in my house and watching fleas swarm up my legs, and the next day, I found that two-week old fleas were hatching... when they swarmed on me and crawled up my legs!!! I am still in flea-hunter mode. My own Dylan just got sterilized and my Charlie is pretty old, so I worry about their constant reactions to fleas. It's getting better, but it requires me turning my house inside out to scrub everything down. For once, I wish I had only my old 30 square meter (300sqft) apartment in the city. Also, my dad was diagnosed with early signs of ALS and Dementia. He's taking it a bit better than the rest of us. Except he got swindled out of 30,000 Kroner (about US$5000), which I luckily managed to track down and get back for him. So yeah, my life is a bit of a mess right now. Still got plans to help kittens, because goddamn does this place need someone to do that stuff right. The whole "every science must be conquered" thing is on hold, and my making games strictly based on my own enjoyment of scientific simulation is equally paused. Once I get back into game development, it's going to be more focused. I am lucky enough to have some friends in the production consulting field, and they are giving me some of their time to see if this game dev stuff can be done better for me. But right now, my head is just spinning. Just when you think things cannot get more insane..... So anyway.... how are you doing??
  2. Temporary radio silence

    Haha, never thought of that! Let us try... Edit: The new post system is preventing me from uploading from my phone, I will fix it later... somehow! THE KITTEN PICS MUST FLOW!!
  3. Temporary radio silence

    Yes, I am being quiet, and if you follow my stuff, sorry about that. I recently made my house available to local animal shelter assstance, and am now living in a "kitten orphanage", caring for 13 abandoned kittens (in addition to my own 2 cats) until they get adopted or move on through the 'system'. Rewardung work, but it leaves very little time for blogging or programming I'll be back again soon!
  4. Gravity systems?

    Again, sorry but I do this out of interest, so I do the things I like to work on. I get your point and advice, but.... no, sorry, cannot agree.
  5. Gravity systems?

    Not to be rude or anything, but..... I feel I am the judge of that. If I want to make a silly little Mario-clone platformer with scientifically semi-accurate star backdrops, that would be my decision. Not saying that is in any way the plan, but since it's my game, I don't really feel I have to "justify" my decisions? Just my opinion. And it being my game, that is the opinion that the final verdict gets based on, after all....
  6. Gravity systems?

    It is about time travel, across millions of years if needed. The universe changes over that timeframe, and I want it to change in a scientifically credible manner, partly because it is meant to convey science, a la 'edutainment', partly because I just want it to.
  7. Gravity systems?

    I used this up till this point, but the problem with random states (the "no movement" is really a non-option) is that A: it lacks the appearance of a system as soon as someone studies it a bit, and B: it is impossible to use back and forth scrubbing in it without filing literally millions of used random states. As a simple background element, it works fine; I already used it plenty! But I am at a point where I need to use something with a more solid structure Ooooooooooohhhh..... this looks yummy!! I am going to chew down on that for some time. It even has multi-purpose use, for fluid dynamics and other fancy stuff! Thanks!!
  8. Gravity systems?

    Yeah, I do seem to be staring at a brick wall here. I've spent the last week or so really reconsidering what I need compared to what I am doing, and maybe this isn't the hill I should choose to die on. I think some approximation will be used from here on in. As long as there is a sense of the progression of time. But right now, I feel a bit burned out by the brick wall It's a time travel game. I really don't need this level of detail, but something just went a bit out of control. What I want is a full universe that ages and evolves, and although the focus is intended mostly on planets evolving, the astronomy part is important, too. It sets up the big stage's depth, so to speak. But yeah, as mentioned above, I have started to reevaluate what is needed and what is just me being nitpicky, because I seem to be stuck at the N-body problem....
  9. Gravity systems?

    Trust me, I have been trying to figure something, anything, out, but I understand the difficulty / impossibility of it. For 3-body, what comes to mind is a shifting barycenter, calculated as a point all its own, according to masses around it. But I am just spitballing, I have no actual idea... RK4 has been mentioned before. It seems versatile, but I have to read up on it. Thanks!
  10. Login issues [new GameDev version]

    Well, it's just: 1: Log in. 2: Accept terms. 3: Return to same page to log in again. I see it on a lot of forum servers these days, I think it's a common issue with current software.
  11. This is actually both to inform and to test if I am even correctly locked in. During sign in, on mobile device (android phone), the website keeps asking me to sign in again and again in some kind of loop. If this post says Embassy of Time, it is just a redundant loop, but still...
  12. Gravity systems?

    I'm going to have to disappoint you on this one.  You are of course correct for two bodies.  This problem was solved by Sir Isaac Newton some 300+ years ago :-) .   Kepler doesn't get the respect he deserves  :P But yes, you are correct. This is an inherently hard problem and there is no analytical solution.  Only numerical ones.  And lots of trickery and faking-it, as is always the case in game programming.     Better stability in general.  Honestly, though, it's probably not worth implementing until you identify a need for it. https://codepen.io/kemick/pen/YQpepN Wrote a quick comparison.  The particles fall (using a constant gravity force) and then bounce back up using a spring force.  The blue lines indicate the starting point and the floor.  The red lines indicate the maximum bounds that the particle has moved. The leftmost box integrates with a bad version of euler. It also explodes very quickly at the given timestep.  (newPos, newVel) += (oldVel, oldForce)  The middle box integrates with symplectic euler integration.  It gains and loses some energy.  At the very least, you should be using this form. (newPos, newVel) += (oldVel, newForce)   The right box integrates using leapfrog. See the source for details since it's a bit longer. So as you can see, for the given timestep the leapfrog method conserves its energy very well.  However, it may not be necessary depending on your accuracy requirements. Thanks, I needed that kind of more 'tangible' thing. I think you're right, leapfrog may be a bit better in some ways, but it would take an immense effort to rewrtie for it (including learning an dunderstanding it), so that will be for a possible future version. It still feels utterly bizarre that there is no conversion-to-static-equation solution. But something tells me others have said the same as me, and then lost decades to finding an answer. The bold should beware, I guess :-o
  13. Gravity systems?

    Definitely going for "close enough"! I will no doubt go for something more advanced later on, but for now, something that is scientifically 'close', but not 'accuracy over usability'.    Decisions, decisions. But you do make it sound pretty good, although I will need to study it much closer! I am starting to think I need a mixture...    I am starting to accept that. I am still holding out hope for something similar that is simply 'science-adjacent'. But that is a future thing, I am trying to keep my eyes on the ball for now...   I am convinced that I will have to do a lot of weighing systems against each other, maybe mix and match. Who would have thought this would be difficult ;-p    No, not trolling, why would I? I am just hoping that there is something I am ignorant of, but hope is failing me on that particular account... :( Thanks! I am shopping around for good stuff, didn't know the Princeton one!
  14. Gravity systems?

    This is the  eternal issue, isn't it. What bothers me is that my brain keeps telling me that there should be a way to compress all the forces into a single equation (possibly one per particle) and find the position of the particle as a function of time. Like if you calculate two bodies influencing each other; you can (to simplify it) calculate a barycenter and simply input the point in time you want to sample their positions and voila, the equation returns the positions. There would be no need for timestep, and CPU pressure is next to nothing (compared tot he current options available, anyway). I have even done some theoretical work on how to move from two to three bodies, hoping that it will let me figure out how to do it with n bodies, but it seems a bit.... challenging. So for now, lesser methods apparently need to be used....
  15. Gravity systems?

    I simply cheated: If a particle is too close, it keeps its velocity unchanged. It then goes by the other and regains enough distance to calculate properly. Yeah, before I did that, those things went flying EVERYWHERE! Not sure I fully understand the advantage of the leapfrog or midpoint? I mean, the implementation seems easy enough, but what do I get out of it? Asfor the octree, I keep getting more keen on it. I have another experiment running 25,000 particles at okay rate, but at some point, I clearly need to familiarize myself with some octree algos!