[HN Gopher] Simulating worlds on the GPU: Four billion years in ...
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Simulating worlds on the GPU: Four billion years in four minutes
Author : xk3
Score : 184 points
Date : 2021-07-25 16:46 UTC (6 hours ago)
(HTM) web link (davidar.io)
(TXT) w3m dump (davidar.io)
| setr wrote:
| Neat. I've been looking for something like this for gamedev --
| being able to model pseudo-realistic simulation of planetary
| evolution (for my interest, just starting at plate tectonics and
| going up until wind patterns) to provide a "basis" for further
| simulation.
|
| It's surprisingly hard to google though; almost all content is
| simple perlin noise generation that looks kind of correct but
| ultimately produces total nonsense (so any further derived rules
| have to also be total nonsense) -- generally constrained with
| further nonsense rules to produce higher level concepts like
| "animals" and "biomes" that can't be touched meaningfully.
|
| Other material I can find is far too involved, and far too slow
| -- targeting actual simulation of the earth. The few that do it
| with the goal of "just realistic enough" still end up being 10+
| minutes generation time for small worlds. Modeling erosion
| processes being the main culprit, afaict.
|
| Definitely stealing this one, for all my nefarious deeds.
| david_ar wrote:
| Author here. This was definitely something I struggled with
| when creating this simulation. Reasonably fast simulations of
| tectonics and erosion have already been done before: some parts
| were tricky to translate to the constraints of a shader, but
| the parallelism pays off in being able to run the simulation at
| interactive speeds. The difficult part was the global climate
| model. I spent a while researching existing methods, but as you
| say, many of these are computationally expensive scientific
| simulations.
|
| In the end I just downloaded some data for the Earth and went
| about seeing how well I could replicate climate maps with some
| simple curve fitting in a Jupyter notebook. After some trial
| and error, I was surprised to find that you could actually
| approximate things quite well with sine curves and some
| blurring, as described in the article.
|
| Overall I learnt a lot about Earth systems from this project,
| it was a fun hobby for a few months. I have some ideas for
| taking it further, but haven't gotten around to it yet. Feel
| free to reach out to me if you have any questions, or want to
| discuss any ideas you have about it.
| R0b0t1 wrote:
| If you have seen the glacier sims with Elmer, maybe start there
| and walk back until the simulation is fast.
| Datagenerator wrote:
| Some very detailed algorithms here [1]
|
| 1) https://github.com/DokimiCU/mg_tectonic
| withinboredom wrote:
| I see stuff like this and then ponder whether I'm living in
| someone's weekend project... it'd be pretty interesting to
| discover the universe is a simulation, but it'd also kinda suck.
| s5300 wrote:
| Our observable universe is just a zany snowglobe knick-knack
| picked up as a last minute gift for a spoiled little shit in a
| universe of higher order than ours that's simply imperceivable
| to us. All of what we know as mass in our universe was
| suspended in a tiny bowl centered in the globe, the kid gave it
| one shake, ala the big bang, then sat it on a shelf forever to
| collect dust as we near unmeasurably slowly eject towards the
| edges of the globe. Maybe one day he'll pick us back up...
| xvector wrote:
| Implies that the theoretical ability to simulate a universe
| (or even just a planet) exists somewhere, which absolutely
| might not be the case
| new_guy wrote:
| No Mans Sky does it pretty well. Who knows? Maybe when we
| get up to PlayStation 10 or 20 it'll actually be simulating
| the cognitive/sentient elements of the universe too.
| hutzlibu wrote:
| Doing something "pretty well" compared to the task and
| doing something complete, is not really the same, when we
| are talking about a possible infinite universe to
| simulate. Because in this case, even just correctly
| simulating the leave of an tree, would take infinite
| comouters.
| romesmoke wrote:
| I don't get why this comment has been downvoted. Isn't
| pessimist poetry allowed on HN?
| MPSimmons wrote:
| Even if the universe /is/ simulated, it wouldn't have an affect
| on anything mundane. We all still need to eat. Suffering is as
| real as anything else, and the alleviation of pain is still a
| good thing.
|
| It also means that there is the potential to exploit the
| simulation, and take advantages of the corner cases - which may
| also get us shut down, but we would likely never know it
| happened, so it's almost without penalty.
| aaron-santos wrote:
| Sure, let's see how throwing some NaNs into the mix works
| out!
| colinmhayes wrote:
| I think therefore I am. Being in a simulation doesn't make my
| experience any less real.
| oxfeed65261 wrote:
| Cogito, ergo sim?
| elliotec wrote:
| Brilliant comment. I'm playing the sims while reading this
| too and one can't help but wonder the extent of their
| sentience
| MH15 wrote:
| Very cool simulation! Also love the John Murphy soundtrack.
| rbanffy wrote:
| Sunshine had this single redeeming quality.
| MPSimmons wrote:
| Great work. Interesting that he didn't simulate the impact that
| formed the moon, though. I'm interested in how that impacted (ha)
| plate tectonics. I'm not aware of a scientific theory that posits
| a causality between the impact and plate tectonics, but we are
| the only rocky planet that has both plate tectonics and a natural
| satellite created by impact, so I have to wonder if they're
| related.
| smoe wrote:
| Not an expert at all but from skimming Wikipedia
|
| "The appearance of plate tectonics on terrestrial planets is
| related to planetary mass, with more massive planets than Earth
| expected to exhibit plate tectonics. Earth may be a borderline
| case, owing its tectonic activity to abundant water"
|
| https://en.m.wikipedia.org/wiki/Plate_tectonics
|
| It is just that there no objects in the solar system big enough
| to have plate tectonics. And we currently have no way of
| detecting them on exoplanets.
| jagged-chisel wrote:
| I'm under the impression that there were no "plate tectonics"
| at the time of impact (surface was still nearly molten), and if
| there were (surface had actually crustified), plates were
| quickly melted by massive amounts of energy from the collision.
| bsenftner wrote:
| The author's github is a cornucopia of delights too:
| https://github.com/davidar?tab=repositories
| wrycoder wrote:
| Of course, CAGW has to destroy life at the end.
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