Posts by Shane Reilly
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1) Message boards : News : Standalone screensaver test available for Linux (Message 48272)
Posted 1221 days ago by Shane Reilly
Update: The speed boost is most apparent for larger blurs. The demo as-is uses blurs that are only a few pixels in diameter so there is, unfortunately, no speed-up currently for the screensaver under OpenGL. It actually runs a few percent slower than my current implementation. There may be a way to do a hybrid approach that will combine the benefits of both approaches, but it does not seem likely since the bottleneck seems to be the transmission of data between the graphics card and the CPU (there are 50,000 blurs drawn per frame). This issue might theoretically be overcome by programming the graphics card directly.

The new implementation does, on the other hand, use substantially less memory, requires less code complexity, shows finer detail with greater color depth, and scales nicely for larger blurs, showing only modest degradation in speed as blur size increases significantly.
2) Message boards : News : Server back up (Message 48257)
Posted 1222 days ago by Shane Reilly
Will the main page of the website be up again soon as well?
3) Message boards : News : Standalone screensaver test available for Linux (Message 48254)
Posted 1222 days ago by Shane Reilly
I have done some in-depth research into using OpenGL for the star-sprites. It seems that a 4x speed-up is a conservative estimate at least on my newest machine. The resulting speed-up could be closer to 10 or 15 times the single-threaded CPU-driven algorithm.

By using "glBlendFunc(GL_SRC_ALPHA, GL_ONE);" I am able to create additive blending without the use of get and put pixel.

Once the new implementation is complete, I will see if it is possible to create a moving screensaver view. At the very least, I should be able to pan images across the screen for a more dynamic effect instead of relying on a slideshow effect.
4) Message boards : News : Milkyway Screensaver Testing (Message 47207)
Posted 1239 days ago by Shane Reilly
I tried both of your demos and while they work, I don't get it I guess. Maybe shooting for being too complex? Suggestion would be to simplify the graphics representation down to something that will fit entirely in the window. I realize my other suggestion I posted in the wrong thread. But this one is more of the same especially after toying with the cube demo and the other one.

My thoughts are perhaps there should be an option for a way more simplified view of it that still looks cool that passerbyes would stop and want to watch. As it is they are probably not there yet. Just my thoughts. :)


It should be relatively easy to fit the demo in the screen by pressing F2 or maybe F4 (increase speed x 10 and x 1000 respectively) and then holding "<" - at least on relatively fast machines ~2ghz or higher.
5) Message boards : News : Milkyway Screensaver Testing (Message 47206)
Posted 1239 days ago by Shane Reilly
The apps used to repair the broken links may be a little out-of-date. I will put up the fixes for non-US keyboards in the next week or so by recompiling the new source.


That seams to be a reply on the 6 months old message posted by Werkstatt
;) Do you live close to Alfa centauri or in an other time frame? :)


It was not meant as a reply to the keyboard issue. Many of the links to the demo applications were broken some time in the last few months. To answer your second question, I am on Mars time.
6) Message boards : News : Milkyway Screensaver Testing (Message 46931)
Posted 1246 days ago by Shane Reilly
The apps used to repair the broken links may be a little out-of-date. I will put up the fixes for non-US keyboards in the next week or so by recompiling the new source.
7) Message boards : News : Standalone screensaver test available for Linux (Message 46915)
Posted 1247 days ago by Shane Reilly
I have looked into this a bit myself. I am looking forward to testing an OpenGL implementation particularly on my lower end machines.
8) Message boards : News : MilkyWay@home screensaver coming soon (Message 46914)
Posted 1247 days ago by Shane Reilly
I am happy to say that I am still unofficially with the project. This last semester has been hectic, but I look forward to getting the screensaver up and running in the near future. It is complete for Windows and Linux, but needs final integration. I have been researching a dozen methods of creating low-maintenance event loops and I believe I have a workable solution for integrating the final application.

This thread is more recent and contains the working demo in case anyone would like to try it out (the broken links have been fixed).
9) Message boards : News : Standalone screensaver test available for Linux (Message 44867)
Posted 1360 days ago by Shane Reilly
"ESA's GAIA will map ~100 million stars, right? Still a long way off from all of them (and I doubt they'll all be part of the milky way), but.."
-Emanuel


My original numbers were misinformed. Currently the largest catalogs I know of have roughly 1 billion relative star coordinates. NOMAD is one example. Also the Tycho II catalog does not contain parallax data which will be available in many upcoming catalogs such as the one you mentioned. The current estimates for the distances of Tycho II stars are not accurate enough to show decent distributions of star density when all of the stars are mapped. The Hipparcos catalog (released in 1997) does contain parallax data of 100,000 stars which allow accurate 3-dimensional coordinates of stars to be mapped.

For those that are interested, here is a simulation showing Tycho II estimations of 2 million stars made by "granthutchison" as a Celestia add-on. The original data can be found here.

showstars_win.zip

Instructions for use are found in the zip file. Star colors were not included in this version.

10) Message boards : News : Standalone screensaver test available for Linux (Message 42914)
Posted 1413 days ago by Shane Reilly
The immediate galaxy is mostly mapped if you only consider relative angles to the Earth. The part hiding behind the central halo is much more difficult to map because the star density is greater there. The distances of the stars are harder to find and mapping them is an ongoing process.

Countries including the US, UK and now China have all had plans for telescopes that are specifically designed for this task. I believe the most complete catalog of star distances is currently Tycho2 which maps 2.5 million stars out of the estimated 300 billion stars in the Milky Way.

MilkWay@Home uses data from the Sloan Digital Sky Survey to narrow in on the structure and evolution of streams in the galaxy. The SDSS maps galaxies and other very distant objects making it possible to map approximate positions of F stars in the Milky Way thousands of times more distant than those in Tycho2. The SDSS has currently mapped more than 6% of the sky (http://www.sdss.org/news/releases/20031028.powerspectrum.html).
11) Message boards : News : Screensaver Demo (Message 42893)
Posted 1414 days ago by Shane Reilly
Someone else had a similar problem. Solution here.
12) Message boards : News : Milkyway Screensaver Testing (Message 42892)
Posted 1414 days ago by Shane Reilly
Unfortunately there was not time to build a key-swap setup file. I can include any suggested key substitutes for your keyboard in addition to the originals. What would you like them to be?
13) Message boards : News : Standalone screensaver test available for Linux (Message 42883)
Posted 1415 days ago by Shane Reilly
Testing applications are now available for Linux now that a major timing bug issue has been taken care of. Windows applications are also updated in the windows thread. Mac applications have been forwarded to the appropriate team members for compilation/testing and should be available soon.

Please feel free to leave suggestions/comments here and bug reports in this thread.

The demo is computationally expensive and will not run sufficiently fast on some machines (runs a bit choppy on a Pentium I5 2.4ghz CPU). The "cube_test" application has a much faster demo that uses the same graphics engine. If either works, the final screensaver should run smoothly on the same machine. The final screensaver will have precalculated paths and images, taking care of the speed issue.

mwdemo_linux.tar.gz (v2)

cube_test_linux.tar.gz (v2)

To use the application, download it and extract it to a folder on the desktop or in another folder if you prefer. Then run either of the two executable files that are extracted. As a precaution, it may be a good idea to save any data in other applications before running the full-screen version. For those that do not have Windows XP or later, a zip utility such as 7-zip or WinZip can be used to open the file. The controls listed below are similar to those of Celestia with a few more added in.

Source for all files can be found here.


CONTROLS

ESC - Exit application
Tab : Start over
Shift-Tab : save new start-point
Alt-tab : leave application temporarily when in full-screen mode
Prtsc or Print-screen: saves a screenshot

MOVEMENT

< / > : accelerate backwards /forwards
F1-F9 : change acceleration (each step is 10 times faster than the previous)

Arrow : look around
Ctrl-arrow : rotate view
Shift-arrow : revolve camera around galaxy center (inverted)
Alt-arrow : accelerate up/down/left/right
Spacebar : stop motion

Backspace : focus on center of galaxy
Shift-backspace : focus on Sol

Enter : travel to center of galaxy
Shift-enter : travel to Sol (gives an Earth view of the wedge)


APPEARANCE

1 / 2 / 3 : select object 1-3 (wedge, stream, galaxy)

+ / - : increase/decrease luminosity of object
Shift- + / - : increase/decrease star blur radius
Alt- + / - : increase, decrease number of stars visible

A : toggle axes view
C : toggle camera view


Notes:

If the application runs a little choppy, then it may help to hold keys a little longer if they do not activate every time, esp 1 / 2 / 3 when choosing an object.

(Alt-minus) and (Shift-minus) will quickly increase the frame-rate since they require fewer screen-writes.

As you move away from the stars, they will combine and brighten. The brightness can be reduced manually (see above).

Update: fixed broken links

Update: added replacement keys for foreign keyboards:
p and m keys replace + / -
b and f keys replace < / >
14) Message boards : News : Milkyway Screensaver Testing (Message 42881)
Posted 1415 days ago by Shane Reilly
A major bug fix has been added that should allow both applications to run on machines that were previously having trouble. The application downloads have been updated in the first post.
15) Message boards : Application Code Discussion : Milkyway Screensaver Bug Reports (Message 42879)
Posted 1415 days ago by Shane Reilly
I am uploading a major bug-fix in the timer routine that may solve this and other problems for the platforms that are having issues. Let me know if it still has any problems.

Edit: fix is now uploaded
16) Message boards : Application Code Discussion : Milkyway Screensaver Bug Reports (Message 42869)
Posted 1415 days ago by Shane Reilly
... most of the control buttons do not work. Is that your intention?

-TJ

Which control buttons are having a problem?
17) Message boards : Application Code Discussion : Milkyway Screensaver Bug Reports (Message 42681)
Posted 1422 days ago by Shane Reilly
I realize now that the demo will not run fast enough on many machines. It runs a bit choppy even on a Pentium I5 2.4ghz CPU. For those that have computers that are more than a few years old, I have posted an application that has a much faster demo that uses the same graphics engine. If either works, the screensaver should run smoothly on the same machine. Please leave a comment here if neither works.

See the first post of the original thread to download the second demo.
18) Message boards : News : Milkyway Screensaver Testing (Message 42680)
Posted 1422 days ago by Shane Reilly
Thank you for the bug reports. I have made a thread here to separate them from the comments/suggestions page and will continue to move relevant posts there.

The demo may not run fast enough on some machines. It runs a bit choppy on a Pentium I5 2.4ghz CPU. The original was much faster, but the addition of color and the prioritization of appearance over speed have made the testing suite calculation intensive. The final product will have precalculated images taking care of the speed issue.

For those that have computers that do not run the first application, the following application is much faster and uses the same graphics engine. If either works, the screensaver should run smoothly on the same machine.

cube_test_win.zip



For those that had trouble with the original demo, feedback on this application would be helpful.

I will add this note to the top of the thread.
19) Message boards : Application Code Discussion : Milkyway Screensaver Bug Reports (Message 42496)
Posted 1429 days ago by Shane Reilly
I fixed comments on some of the controls. It should make more sense now. Thank you for the heads up.
20) Message boards : Application Code Discussion : Milkyway Screensaver Bug Reports (Message 42461)
Posted 1431 days ago by Shane Reilly
Bug reports can be left here for the Milky Way Screensaver and standalone application.

Known issues:

axes are not displayed correctly at close angles.


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