Re: X hardware acceleration still flaky?

[<L dot Wood at surrey dot ac dot uk>]

On 9 Aug 2010, at 17:30, Jon TURNEY wrote:

> On 09/08/2010 15:08, L.Wood@surrey.ac.uk wrote:
>> Hi Jon,
>> 
>> the lack of flickering and lack of double-buffering you describe sounds like geomview being run without opengl, either  because it has been compiled without opengl (still the default if you just type ./configure, I believe), or because
>> geomview -noopengl
>> was issued. Did you build Geomview with --with-opengl, and have you turned on a texturemapped Earth showing coloured continents? (If geomview issues a 'Shared memory unavailable, using fallback display method' to stderr at launch, it's not using OpenGL.)
> 
> Yes, I have configured geomview with --with-opengl.
> 
> No, I didn't turn on texturemapped earth, because your report didn't mention 
> that. Does this mean turn on "Texture mapping" in Savi's rendering menu (which 
> appears to be on by default) or "Use simple/detailed earth map"?

Yes, my report didn't mention texturemapping; it wasn't needed for the crash. But, to stress things and see if a crash can be provoked, it's worth putting into operation.

Texturemapping is enabled by default, yes. But SaVi defaults to a blue sphere, because it can't be sure Geomview and the display support OpenGL or texturemapping, so by default doesn't try to do anything fancy with texturemapping. To turn on texturemapping turn on 'Use detailed Earth map'. That should then show colourful landmasses when texturemapping is enabled.

Opening the Coverage panel (Views menu/Global Coverage...) and turning on sending the coverage map to Geomview from the coverage panel's Rendering menu and then pressing >> in the animation bar (at the bottom of each window) to animate will force dynamic texturemapping and pipe the coverage maps to Geomview, so that Geomview's camera window is always updating. That's the best way I know of to stress texturemapping.

The reason for doing this - if this all works and we see a bitmap animating on the sphere, OpenGL and texturemapping are definitely working under stress/load. If we're only looking at a stationary default blue sphere, we can't really be sure what's working.

> If I run geomview -noppengl I get no flickering even when rotating the planet.
> 
>> When geomview is run with opengl, I see consistent flickering at every single animation stage, not just when dragging with the mouse. -noopengl is much smoother. (I'm using a fairly high-end Core2Duo with graphic card.)
> 
> Do you have something to make an animation start automatically when savi 
> opens? I just get a static planet and z,y,x axes unless I drag it around with 
> the mouse.

See instructions above. Once texturemapping is turned on and SaVi is sending coverage maps to Geomview to render, the load can be fairly large. You can select e.g. the Iridium constellation from the constellations menu so that there's a lot of visible animation. Pressing the >> button starts animating.

>> I've now realised that my crashes only occur when I use the second screen attached to my machine. (Mea culpa - I take multiple screens for granted.) When geomview's camera is on the root (laptop) screen, X doesn't crash, even when texturemapping, and I get slow but flickery animations of texturemapped Earths. Move it over to the second screen and do something that invokes texturemapping like turning on a detailed Earth - goodbye, Mr X.
> 
> I am also using multiple monitors.
> 
>> It's a little odd that XWin.0.log doesn't explicitly call out the two screens as such - it knows the primary (laptop) monitor is 1280 by 800, and that DIB has a height of 1824 because there's a 1280x1024 screen positioned above it.
> 
> Although the logging could perhaps be clearer, -multiwindow implies 
> -multimonitors by default which gives a single X screen the size of the 
> Windows virtual desktop.

okay, that much makes sense.

> 
>> Is it still useful to give you a bt from gdb?
> 
> Yes, please.

Right, thanks for gdb --pid= capture instructions in other mail; screengrabs of bt (if cygwin terminal supports copy and paste, I couldn't figure it out...) in private mail to you.


cheers,

L.

> 
> -- 
> Jon TURNEY
> Volunteer Cygwin/X X Server maintainer

Lloyd Wood
L.Wood@surrey.ac.uk
http://sat-net.com/L.Wood




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