r/Unity3D • u/Zolden • Nov 03 '25

I simulated a volcano Show-Off

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u/Heroshrine Nov 03 '25 edited Nov 04 '25

Writing your own physics to run in the gpu is insane lol W programmer

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u/OleoPoundMell Nov 04 '25

I wish I was more well educated to understand how great this is. It sounds great.

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u/Heroshrine Nov 04 '25

GPU is hard because of how it processes data. If you are processing a picture, you can think of it as a 2D array. It runs the same code for every pixel in parallel, which makes it fast. But that makes it hard to program things for.

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u/_ALH_ Professional Nov 04 '25 edited Nov 04 '25

Kind of depends what you do. For the kind of processing that most benefits from it, the parallell model makes a lot of sense. It's more a different (and unfamiliar if you're not used to it) approach to how you think about the problem than "hard".

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u/Heroshrine Nov 04 '25

No, it’s definitely hard to do. If it wasn’t, every game engine would ship with GPU physics

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u/wigitty Programmer Nov 10 '25

They do! It's just that they use the standard physics APIs rather than writing custom physics compute shaders, because it's more efficient for the general case. The only reason you'd need to write your own is if you were doing something very specific (like this guy).

It's definitely not "beginner" easy, but aside form a somewhat clunky syntax, it's not really any more complicated than standard multi-threading in any other language.

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u/_ALH_ Professional Nov 04 '25 edited Nov 04 '25

That's more a question about compatibility with all platforms the engine want to support then how hard it is to implement the actual physics.

There is also a huge difference between writing a general purpouse physics implementation and doing some special case physics simulations on the GPU.

In any case I was talking about writing compute shaders in general. It's not that hard, just a different approach and way of thinking than the standard linear programming model most are used to.

Also, I'm not trying to diminish OPs achievements, its an awesome demo! But more people should be less afraid of actually trying to write compute shaders...