FreeGameDev

Steve, you are in danger of having a good looking game on your hands!

This is quickly turning into one of my favourite FOSS game projects.

Just a little teaser pic, will probably post a new video tomorrow...



Those nebula are not baked into the skybox, they are 3 dimensional and you can drive through them.

Also, quite likely the forum has silently clipped the image, press ctrl-minus a few times to see the whole thing.

Edit: Here's another teaser pic, some space rocks and behind them some nebula goodness. This thing is like driving the Hubble around... except with lasers.



Same caveat about pressing ctrl-minus or right-click, "view image".

Or right-click and press "See image" or so.
Looks good!

Looking really good!

I'll just leave this here...

https://www.youtube.com/watch?v=-dVLMqKm4d8

Holy Rings of Saturn, Batman!

Just a short video for now -- now NPC ships use warp (aka jump) drive (which is represented by the bright flashes you see in the video):

https://www.youtube.com/watch?v=1MoVUdvWy8Y


Oh yeah, Zach Schultz made an awesome modified and textured model of the "wombat" spaceship...

Looks awesome! We are soon giving SNIS a go at work ^_^

February 2014 devlopment update:

https://www.youtube.com/watch?v=LwzWGQ255cI

Looks great! I will soon have to try another shot at doing a dedicated snis-distro ^_^

Development update for March 2014...

https://www.youtube.com/watch?v=JQDhI2FeLUg

Space Nerds In Space April 2014 Development update.

Kind of slacking off lately in terms of committing code to Space Nerds In Space. That's ok, it's expected that there will be occasional lulls in momentum for any hobby project of this size. Look at Word War vi -- plenty of gaps in the commit history when enthusiasm waned.

Anyway, I have by no means abandoned the project. Here's a little video of what's new this month:

https://www.youtube.com/watch?v=oJRhO7ur8YA


The audio isn't sync'ed to the video, and the video runs out before the audio finishes, ... oh well.

Most notably, I've been getting into emulating some fluid dynamics stuff to try to get decent textures for gas giant planets. I've made some progress mostly by pursuing the ideas in this paper: Curl Noise For Procedural Fluid Flow by Bridson, Hourihan and Nordenstam. You can the current state of my experiments here: Curly Vortex on github.

What it looks like in game so far (this is not committed because I'm not yet satisfied with it.)


The fluid flows on that planet image were simulated (faked) on 6 square faces of a cube arranged in a field of perlin noise with particles moving to adjacent faces when they leave another face. This works ok, but not great, leaving visible artifacts (though less artifacts than wrapping a seamless rectangle around a sphere). It also does not work well if you want to introduce belts of counter rotating flows parallel to the equator of the planet -- things get a little too tricky for me near the edges of faces and on the top and bottom squares of the cube. I think the better way to do it is do the flows in real 3d on the surface of the sphere, then generate the cube map textures from that data, which is what I'm currently working on, but it's not really there yet.

In the mean time, here some examples of 2D fluid flows with horizontal bands of flows alternating between left and right with chaotic zones between. imgur album here.

I following your project since the start when you posted on this forum and I'm impressed by all the continued effort you have put in it.

It is already far from these times. Keep it up!

smcameron {l Wrote}:What it looks like in game so far (this is not committed because I'm not yet satisfied with it.)
[awesome pics]

I just looked back and came across this in the 2nd post of the thread:

smcameron {l Wrote}:No 3d "thru the window" view yet --- if I do it, it will be a totally software z-buffered flat-shaded triangle renderer that looks like it's from a 1982 silicon graphics workstation. You'd probably rather someone besides me programs that bit, lol. As would I, as would I.

Hrm... are these two the same guy? I'm unsure.

Beautiful idea to use curl of noise function to get divergence free velocity field.

smcameron {l Wrote}:The fluid flows on that planet image were simulated (faked) on 6 square faces of a cube arranged in a field of perlin noise with particles moving to adjacent faces when they leave another face. This works ok, but not great, leaving visible artifacts (though less artifacts than wrapping a seamless rectangle around a sphere). It also does not work well if you want to introduce belts of counter rotating flows parallel to the equator of the planet -- things get a little too tricky for me near the edges of faces and on the top and bottom squares of the cube. I think the better way to do it is do the flows in real 3d on the surface of the sphere, then generate the cube map textures from that data, which is what I'm currently working on, but it's not really there yet.

You say you have tried Latitude / Longitude Projection (seamless rectangle)? Did you scale vx or dx to account for changing circumference cos(lat)? Should be simpler than trying to get the Cubed-Sphere Grid (cube map) right I think.

Edit:
Using spherical coordinates for particles positions and velocity should work for cubemaps I think. You just have to figure out the transform from spherical to cubemap coords

charlie {l Wrote}:

smcameron {l Wrote}:What it looks like in game so far (this is not committed because I'm not yet satisfied with it.)
[awesome pics]

I just looked back and came across this in the 2nd post of the thread:

smcameron {l Wrote}:No 3d "thru the window" view yet --- if I do it, it will be a totally software z-buffered flat-shaded triangle renderer that looks like it's from a 1982 silicon graphics workstation. You'd probably rather someone besides me programs that bit, lol. As would I, as would I.

Hrm... are these two the same guy? I'm unsure.

Well, as it happens the bulk of the gnarly opengl coding was done by someone besides me.

And I didn't commit those textures because I didn't want to bloat the repo with commits of huge binary graphics files I knew would not last long.

NaN {l Wrote}:Beautiful idea to use curl of noise function to get divergence free velocity field.

smcameron {l Wrote}:The fluid flows on that planet image were simulated (faked) on 6 square faces of a cube arranged in a field of perlin noise with particles moving to adjacent faces when they leave another face. This works ok, but not great, leaving visible artifacts (though less artifacts than wrapping a seamless rectangle around a sphere). It also does not work well if you want to introduce belts of counter rotating flows parallel to the equator of the planet -- things get a little too tricky for me near the edges of faces and on the top and bottom squares of the cube. I think the better way to do it is do the flows in real 3d on the surface of the sphere, then generate the cube map textures from that data, which is what I'm currently working on, but it's not really there yet.

You say you have tried Latitude / Longitude Projection (seamless rectangle)? Did you scale vx or dx to account for changing circumference cos(lat)? Should be simpler than trying to get the Cubed-Sphere Grid (cube map) right I think.

Edit:
Using spherical coordinates for particles positions and velocity should work for cubemaps I think. You just have to figure out the transform from spherical to cubemap coords

Yeah, I think I know how to do it, just need to actually do it, and debug it. I don't think I can run the sim on the faces of the cube map easily, or I can't figure out how to get rid of velocity discontinuities at the edges of the faces, and it makes doing counter rotating velocity bands more complicated than I can deal with. After trying for awhile I have concluded it would be easier to do the sim in 3d proper, and get the cubemap images from the 3d data.

So I have spent the last several days trying to do a proper 3D version of my fake fluid flow stuff.

Having some problems.

1. Cannot seem to get a divergence free velocity field on the surface of a sphere like I can for a 2D plane. Not totally sure why. Might have to do with error deciding if the noise gradient is "uphill" or "downhill". Adding a fudge factor to correct (somewhat) for one error in that area helped (reduced divergence) but what i thought should be a perfect correction was worse than the fudge factor. So... yuck. Not sure what's going on there.

2. Still have issues with discontinuities at cubemap face boundaries. Drat. The whole point of doing the sim in real 3D was to get rid of those. Haven't really tried to debug that, might turn out to be something simple, but... not happy to see those discontinuities.

3. libpng sucks. The initial particle colors are taking from an starting image. Right now that image must be 1024x1024 or it won't work. That's due to me not being able to figure out wtf is going on with libpng. Seems like it should be simple, but... it is the exact opposite of simple. Or I'm suffering some kind of brain lock on the issue, I don't know. Spent entirely too much time on it before just manually scaling the input image to the same size as the output images and giving up on that aspect for the time being. (if 1 and 2 can't be solved, 3 doesn't matter.)

Oh, btw, if you want to play with this mess, I checked it into master of space-nerds-in-space repo on github. The program is gaseous-giganticus. You will need a 1024x1024 png image as a starting point in the current directory that is named "gas.png" (you have to make this yourself. I suggest some cropped image of sedimentary rock formations from arizona found by google image search. Antelope canyon is also a good gis term. but anything will do, so long as it is cropped/scaled to 1024x1024 and name gas.png.) Then it will dump out (and overwrite, many times) files called tmpg-0.png (and 1,2,3,4,5 as well as 0). You can view those with, e.g. gqview or other image viewing program, and also mapped onto a sphere with mesh_viewer (part of space nerds in space code) by "mesh_viewer -p tmpg-" command.

A pic of one cube map face output. The gray areas, and esp. gray areas bordered by black with particles leaving the area are the divergences.



And on a sphere:


Those are with, iirc, 1M particles. 8M particles looks a bit better (divergences are somewhat hidden by the mass of particles.)

-- steve

I've been following your project for quite a while, and I must say it's incredible! (I plan to try it with my friends when it's possible).

Anyway, as libpng sucks, I usually use stb_image: http://www.nothings.org/stb_image.c , which is wizardry at it's best (you just stbi_load at stuff and you get an array of pixels back). That's, unless you got things to work, which is even better

Fixed a few problems.. it's working pretty well...

That is stunning. Well done.

Pretty cool, thumbs up!

Some more progress on the procedural gas giants...