FBO Particle System

[Dream of Omnimaga]

Do you plan to expand this further or even use the engine in a game, by the way?

[Snektron]

I was actually thinking of making some things like emitters, attractors, black holes etc. But ill have to see :p

[Dream of Omnimaga]

Maybe miotatsu could use it for magic spells in Piworld

[Snektron]

You forget that PiWorld is in C and my particle system in Java . Though it shouldnt be too hard to port it

[Dream of Omnimaga]

Oh right, I forgot about that. How does it run so fast though? (seeing how laggy Minecraft could get back then)

[Snektron]

That's because it uses the GPU to handle updates .
The only thing java does is some shader code and the update loop. Basically the position and velocity are stored in 2 textures. Then i use a technique called render to texture which updates the pos and vel tex. Then the pos yex is rendered to the screen. (ill explain a bit more later, dont have time atm)

[Dream of Omnimaga]

Oh right, I always forget about the GPU.

[Duke "Tape" Eiyeron]

It's funny how this *simple* program made me rethink about my general knowledge on the computer programing model. USing GPUs as anything other than 1337 games rendering became quite useful and we should now take them in account when developing heavy programs. I'm not saying anything not obvious but heck, tell the guys which made the GeForce 256 that one day we could use their future GPUs for processing medical samples, rendering epic GFX for movies or just process a frigging lot of data not related to polygon sorting!

[Snektron]

rendering epic GFX for movies

You think they are not used for that? Even blender has a build in mode which renders using the GPU . Also, the amount of data they can proccess makes them excellent for btc mining. Oh and using the gpu for things like you suggested is called GPGPU, you might want to read up upon that

[Duke "Tape" Eiyeron]

rendering epic GFX for movies

You think they are not used for that? Even blender has a build in mode which renders using the GPU . Also, the amount of data they can proccess makes them excellent for btc mining. Oh and using the gpu for things like you suggested is called GPGPU, you might want to read up upon that

I was specefically talking about such uses of the GPUs.

[Dream of Omnimaga]

Then there are also 4K demos. Those look really impressive considering they fit under 4 KB of code. I wonder if they would run on older computers or if they just use slower code shortcuts in order to keep size to a minimum? On calcs, some people will optimize for size and it will slow the game down, but at one point you can't really optimize for size anymore because it will get so slow on such older CPU/lack of GPU that the game will become unplayable. But on higher end computers even the sky isn't the limit.

[Snektron]

With a bit of dirty code i can prop this all in one class file under 4K too. But modern GPU's have enough vram for quite a lot of data (except for the crappy 2mb integrated ones).

[Dream of Omnimaga]

But I remember that many games before that required a 32 MB GPU would often not run on my 64 or 96 MB integrated Intel GPU. Sometimes they also require pixel shader support or various other things. Does your particle system require such dependencies or others?

[Snektron]

Well, yeah, but i've implemented a check in my partile system to see if the GPU has the needed features (Shader support, FBO support, OpenGL >= 3.0). Also it needs at least texsize*texsize*2*4*2*2 + texsize*texsize*4*4 bytes of vram (4 4-component 16-bit textures for pos and vel (2 for reading 2 for writing),  and a 4-component (vec4) 32 bit float point cloud with the same amount of vertices as the number of pixels in the pos texture).

texsize	vram needed
512	12.6 MB
1024	50.3 MB
1536	113.24 MB
2048	201.3 MB
2560	314.6 MB
3072	453.0 MB
3584	616.6 MB
4096	805.3 MB

And that doesn't include the Shader's size

[Duke "Tape" Eiyeron]

CPU VRAM or GPU VRAM?