weird overlay effects in OpenGL painter on NVidia

Bug #1096050 reported by gzotti on 2013-01-04
14
This bug affects 3 people
Affects Status Importance Assigned to Milestone
Stellarium
Fix Released
Low
Unassigned

Bug Description

Uncritical bug IMHO, no action required, just for the record:

Testing 0.12beta1/win64 on Win7-SP1 with NVidia GTX 580M, Driver 295.73.
Launch in --safe-mode (old OpenGL1 painter). Call script phobos-phun3, switch off atmosphere. There are strange overlay effects between the bright solar disk (which apparently breaks apart into several layers) and the black phobos disk (somehow slicing through the sun.) There are also flickering/shifted pixel artifacts between Phobos and the background of stars and grids.
It is OK with atmosphere on, and when running in (regular for NVidia) OpenGL2 mode.

To compare, on an Atom N450 netbook (supports OpenGL1 only), the win/32bit version runs OK, no artifact.

Conclusion: use the renderer your platform supports best...
G.

gzotti (georg-zotti) on 2013-01-04
Changed in stellarium:
importance: Undecided → Low
gzotti (georg-zotti) wrote :

I just updated NVidia drivers, same issue with current drivers 310.70.
G.

Changed in stellarium:
status: New → Confirmed
gzotti (georg-zotti) on 2014-08-14
Changed in stellarium:
assignee: nobody → gzotti (georg-zotti)
gzotti (georg-zotti) wrote :

Test with 0.13: Even stranger: Built from trunk with Qt5.2.0/MinGW, debug or release builds, Phobos is now invisible. No black disk over the sun. The official builds 0.13 and Tests 0.13.0.80 are OK.
I see no reason for this behaviour.

Alexander Wolf (alexwolf) wrote :

I can confirm last point - we have broken eclipses O_O

Alexander Wolf (alexwolf) wrote :

Revision 6953 broken the eclipses.

Alexander Wolf (alexwolf) wrote :

OK. Georg, I temporary fix it: http://bazaar.launchpad.net/~stellarium/stellarium/trunk/revision/6968

Please see comment inside code.

gzotti (georg-zotti) wrote :

Ouch! Sorry :-O

Hmm, occultations (or solar eclipses) by asteroids was not what I was thinking about when trying to improve the asteroid times...
Thanks for your solution. What is now open is proper handling of occultations (of stars)/transits (of sun/planets) by asteroids. Maybe leave a comment on that in the code?

Else, this 0.12-bug can be closed. There is no more OpenGL1 renderer.

Changed in stellarium:
status: Confirmed → Fix Committed
Alexander Wolf (alexwolf) wrote :

Oops... My second patch are broke the occultations of stars by asteroids IMHO (It should be checked!). Possible we should use the optimization for asteroids inside MinorPlanet class. Your opinion?

Changed in stellarium:
milestone: none → 0.13.1

Having the same code in the MinorPlanet class will not help, it is just 1
test less. And removing the brightness test will make the asteroids slow
again.
If a mag15 asteroid occults a mag7 star at sky limit magnitude of 12, the
asteroid will not be drawn after the sky brightness test.

Not sure, has this ever been used for planning occultations? This is
something found on specialized websites.

I think, with all the GPUs available now, maybe the orbit computation
itself for 12000 objects should be transferred to a compute shader in the
long run (requires OpenGL4.3, though...). Shall we Blueprint that?

On Mo, 18.08.2014, 00:18, Alexander Wolf wrote:
> Oops... My second patch are broke the occultations of stars by asteroids
IMHO (It should be checked!). Possible we should use the optimization
for asteroids inside MinorPlanet class. Your opinion?
>
> ** Changed in: stellarium
> Milestone: None => 0.13.1
>
> --

Alexander Wolf (alexwolf) wrote :

> Not sure, has this ever been used for planning occultations?

I know that some people uses Stellarium for visualization of occultations stars by asteroids.

I think idea for blueprint for compute shader is very good and we should write it.

Changed in stellarium:
assignee: gzotti (georg-zotti) → nobody
Changed in stellarium:
status: Fix Committed → Fix Released
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