[osg-users] OSG and NVX_gpu_memory_info

[Garth D]

Hi Robert,

On 30/09/15 19:50, Robert Osfield wrote:> HI Garth,
 > Sorry for the typo, the setRealizeOperation is what I was referring to.

Not a problem, thanks for the clarification.

 > If you want to check periodically then just use a Camera::DrawCallback
 > attached to the main camera attached to the GraphicsContext/Window of
 > interest.  This will be called every frame, but within this callback you
 > could have your own check to see if the GL calls are required for that
 > frame.

Thanks. This was one of the configurations I had tried (with 
setInitialDrawCallback() and setFinalDrawCallback()), and the one I had 
the best hopes for. Unfortunately the calls failed. I'm not certain, but 
I seem to remember that other GL calls worked fine in this setup, and 
that it was only the calls related to NVX_gpu_memory_info that were 
failing. Perhaps this is all an oddity relating to NVX_gpu_memory_info 
specifically?

I also want to try this the setup you describe here *exactly*, in case 
this changes the result.

At this point I think I'm going to have to put something minimalistic 
together and have an further experiment with it. I'll post a follow-up 
when I've got some results.

Cheers,
Garth

 > On 30 September 2015 at 10:56, Garth D <garthy_gso at entropicsoftware.com>
 > wrote:
 >> Thanks for having a look at things and for the suggestion.
 >>
 >> On 30/09/15 17:35, Robert Osfield wrote:> HI Garth,
 >>> I'd use a RealizerOperation.  Have a look at the osgvolume example 
to an
 >>> example of using a RealizerOperation to get information from the 
graphics
 >>> context.
 >>
 >> I was unfortunately unable to solve the problem. Here is what I tried:
 >>
 >> I checked the osgvolume.cpp source for 3.2.1 and 3.4.0, but did not 
find a
 >> RealizerOperation in either.
 >>
 >> I did notice that osgvolume does also use 
viewer.setRealizeOperation() for
 >> TestSupportOperation, defined earlier. Is this what you are 
referring to?
 >> Assuming yes: This is the way I was able to successfully query the
 >> information once only at the start of the program. Unfortunately I 
need to
 >> query the information periodically, ie. over the course of the program,
 >> rather than just at initialisation. Unless I am mistaken, the target of
 >> setRealizeOperation is only called the one time, on viewer 
realization. Is
 >> this right? If so: Is there a corresponding call that I can use to 
attach
 >> an osg::Operation or similar to in order to make the required calls
 >> periodically? If not: Is there a way to indicate that the operation 
should
 >> be repeatedly called?
 >>
 >> Or is there another part of osgvolume.cpp that I should be looking 
at? The
 >> only glGet* call in the file is in TestSupportOperation, which is 
set using
 >> setRealizeOperation(), so I think I am looking in the right place?
 >>
 >> I'll continue to experiment. Thanks again for the suggestion. Is there
 >> anything else I should try?
 >>
 >>> On 30 September 2015 at 03:49, Garth D 
<garthy_gso at entropicsoftware.com>
 >>> wrote:
 >>>
 >>>> Hi all,
 >>>>
 >>>> I was wondering if anyone has been successful in using the
 >>>> NVX_gpu_memory_info extension with OpenSceneGraph, and the best 
place to
 >>>> call glGetIntegerv to get the associated values.
 >>>>
 >>>> Details on the extension here:
 >>>> https://www.opengl.org/registry/specs/NVX/gpu_memory_info.txt
 >>>>
 >>>> I'm using Linux, OSG 3.2.1, and a card that supports the
 >>>> NVX_gpu_memory_info extension.
 >>>>
 >>>> I have tried querying the current and total memory using
 >>>> GPU_MEMORY_INFO_TOTAL_AVAILABLE_MEMORY_NVX and
 >>>> GPU_MEMORY_INFO_CURRENT_AVAILABLE_VIDMEM_NVX, and in each case but 
one,
 >> the
 >>>> values reported back are zero.
 >>>>
 >>>> The only success I have had thus far has been querying the values 
via an
 >>>> osg::Operation set with ViewerBase::setRealizeOperation() on my viewer
 >>>> (osg::Viewer). The values returned appear to be correct. This 
allows me
 >> to
 >>>> get the correct values *once* at the start of the program.
 >> Unfortunately I
 >>>> need to query them periodically, and I have been unable to do this.
 >>>>
 >>>> So far, I have tried hooking the calls into:
 >>>> - An osg::Camera::DrawHandler, set via
 >>>> osg::Camera::setInitialDrawCallback().
 >>>> - An osg::Node::NodeHandler, hooked into the root node via
 >>>> osg::Node::setUpdateCallback.
 >>>> - An osg::Drawable::DrawCallback, hooked into a dummy chain off 
the root
 >>>> of: osg::Node -> osg::Geode -> osg::Geometry (osg::Drawable), via
 >>>> osg::Drawable::setDrawCallback.
 >>>> - An osg::Drawable::CullCallback , hooked into a dummy chain off the
 >> root
 >>>> of: osg::Node -> osg::Geode -> osg::Geometry (osg::Drawable), via
 >>>> osg::Drawable::setCullCallback.
 >>>> - An osg::Camera::DrawHandler, set via
 >>>> osg::Camera::setFinalDrawCallback(). Only partly-tested due to a
 >>>> race-condition that occurs in my code, but appears to fail.
 >>>>
 >>>> I have experimented with osg::GraphicsContext::makeCurrent() with 
each.
 >>>>
 >>>> Can anyone suggest a better place to hook these calls into? Or
 >>>> alternatively confirm that they have the extension working with one of
 >> the
 >>>> above, so I can change or experiment with my existing setup to try to
 >> make
 >>>> it work?