Oolite Bulletins

GlobalExplorer wrote:

I am not sure if I get it. Do you suggest a program should simulate the sensitivity of human eyes and make the fainter stars disappear once a planet is in your field of view, but switch them back on when it's not? No disrespect but that would be one of the craziest ideas I heard in a long time

No it's not. On of the options in Stellarium, particularly useful when talking about moon glow.

Cheers,

Drew.

GlobalExplorer wrote:

I am not sure if I get it. Do you suggest a program should simulate the sensitivity of human eyes and make the fainter stars disappear once a planet is in your field of view, but switch them back on when it's not? No disrespect but that would be one of the craziest ideas I heard in a long time

Oops, I missed this. The answer is: yes, absolutely. I’m assuming that by “render believeable space” you mean that you’re striving for realism, not just trying to present data. These days, achieving something that people will see as realistic means at least some degree of HDR. A scene containing both an illuminated planet and a star background has very high dynamic range.

A relatively simple way of dealing with this would be to estimate the overall light in the scene, which is quite easy for spherical planets and suns, and use this to control an overall intensity “dimmer” for the starry background. When the sun is in view, no other stars should be visible; when the sunny side of the Earth is in view, only a few should be.

To get a scene with a clear starry background and a nearby planet in in real life would require taking two shots, one with the planet masked out, and compositing them together. This is essentially HDR with deliberately bad tone mapping. (This technique is used to create composite images of the sun’s surface and corona, for instance.)

I think this is what I said too - but you put it much better (as usual )

<- sorry double post ->

Ahruman wrote:

I’m assuming that by “render believeable space” you mean that you’re striving for realism, not just trying to present data.

No, I can't remember using the word 'realistic' even once. I think I said 'believable', not realistic. Discussions about complete realism in computer simulation are imho futile, and often filled with anger.

What I meant was something that looks more believable than most games currently available. This means avoiding cheesy colors and hollywood effects, using textures matched to real imagery, and so on.

Besides, realism and interstellar travel don't go that well together anyway.

drew wrote:

No it's not. On of the options in Stellarium, particularly useful when talking about moon glow.

Okay, it's not. Simulating perception of the human eye is an interesting idea, but not one that I give high priority. Still, it's something that I haven't thought of before, so thanks.

GlobalExplorer wrote:

I think I said 'believable', not realistic.

Fair enough. Still, very few people are aware of the look of actual constellations, with the possible exception of the big dipper. All the extra work you're putting in might be totally wasted on the hypothetical 'unwashed masses' that might have been transfixed by Hubble's nebulae pictures, and might well believe that that's what the majority of the sky looks like once outside the atmosphere.

I must say I too did understand 'believable' to actually mean 'realistic'.

I do find it slightly unbelievable when dim stars show next to bright bodies, but I don't really mind it, just as I don't really mind big & bright nebulae inside Oolite!
Of course, your mileage may vary!

DaddyHoggy wrote:

I think this is what I said too - but you put it much better (as usual )

I certainly put it longer. Or should that be “sesquipedalianlier”?

farcry 2 does this HDR thing, it's quite impressive as an effect but it doesn't half make the game hard to play, when you run in-and-out of shadow and your in game characters 'eyes' have to adjust, so you just opt to play the missions at night and miss out on all the lovely daylight effects they built into the game!

Griff wrote:

farcry 2 does this HDR thing, it's quite impressive as an effect but it doesn't half make the game hard to play, when you run in-and-out of shadow and your in game characters 'eyes' have to adjust, so you just opt to play the missions at night and miss out on all the lovely daylight effects they built into the game!

We find that a lot when teaching - people cry out for realism - they get it - and cry out for something simpler!

Be careful what you wish for, as the maxim goes...

I'm just glad that at the moment we can run around in video games without having to run around in front of the telly in real life, i'm going to have to stop gaming if that ever happens, waving my arms around on the Wii puffs me out and that just navigating the 'channels menu' trying to get the game to start *boom-tish*

Griff wrote:

I'm just glad that at the moment we can run around in video games without having to run around in front of the telly in real life, i'm going to have to stop gaming if that ever happens, waving my arms around on the Wii puffs me out and that just navigating the 'channels menu' trying to get the game to start *boom-tish*

Allegedly Wii 2 Wiiremote will be optional - designed to be bodily controlled - and of course there's the thought controlled applications just around the corner. <Firefox>Think in Russian</Firefox>

I worked on my athmospheres and colors. I found that my light model was somewhat off which resulted in much too bland colors, so there is now some real improvement. Examples are the usual clouded Mars and for comparison the same material on Earth.

Earth looks nowhere near where I want it to be. I think I will not make much progress if I don't learn how to make shaders for athmospheric scattering. If anyone should know how to make a cg athmosphere shader, I could use help! That stuff is way over my head.





The new colors should be visible in these screens, and make the planet appear more life like, hopefully.

Big Wow! Big round of applause!

Glad you like it. Currently it's a lot of fun because I find out new things every day.

Some remarks for people who download my demo:

- the latest screens (clouded mars, earth) are made with a new version 3 which is not yet released
- there is not much you can do in the demo except look at the planets from different viewpoints
- the demo is not optimized for performance, so you might low fps or even crashes if you have an old CPU / small video RAM. It runs absolutely fluid on a 3Ghz CPU and 1GB VRam)

The main point of downloading now is testing and initial impressions. But you help me a lot if you do it. If you do get crashes etc, please report back with one or two sentences about your OS and hardware.

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With more experimenation I found that I can improve the athmospheric effect if I add a third layer to my planets. So far I used only a surface and a transparent clouds layer on top, but now I put an air layer in between the two, and it looks much better.

A nice effect of this is that I can also modulate the overall color of a planets only by using different air layers. As long as I can accept the samishness of terrain features, it looks like there is almost endless possibilities for new planet colors.

I think Earth looks much better now. Opinions on this latest version of Earth are especially welcome.









Something a little more weird:




I got Jason Bevins libnoise complex planet example working [link]. The results that can be achieved with Jasons method are very nice! It means I can now generate an infinite number of Earth like worlds. Unfortunately that doesnt help at all for moons, gas giants etc ... but see yourself, this isn't Earth this time:



While I find earth type planets are actually kind of easy, some other types are more tricky. Here some example of my new material framework, which I hope will enable me to randomly generate a large number of worlds from a small number of textures. This is work in progress from dense and very_dense athmosphere classes.

Mars under a cloud cover like Venus:



I am making progress with randomly combining textures. Ultimately the results depend of the textures used, so all I have to do is adding better ones if I have them.



I am also experimenting with a technique to show sunrises, but there are still problems with this.