Based on your comment about how your setup doesn't support GL/CL sharing, I tried defining FLG_FOSPHOR_USE_CLGL_SHARING as 0 in private.h. Not sharing GL objects fixes the pixelated spectrum issue! No more cl_clear_queue_clear_buffers errors either, because the code never goes down that path anymore.

It seems to me there is a bug in the way the histogram buffer or texture is allocated when it is allocated through the GL code path. I'm not sure if this is quirk of my setup/GPU/driver, or if this is a general bug; I do have an older NVIDIA GPU and another machine on which I can try to reproduce what I'm seeing.

Final question, what are the main downsides to NOT using CL/GL sharing? Is there some extra copy/performance overhead?



On Sun, Feb 5, 2017 at 2:36 PM, Raj Bhattacharjea <raj.b@gatech.edu> wrote:
On Sat, Feb 4, 2017 at 4:44 AM, Sylvain Munaut <246tnt@gmail.com> wrote:
Hi,

>> I'm using the latest fosphor from git
>> (7b6b9961bc2d9b84daeb42a5c8f8aeba293d207c) and am seeing two weird (and I
>> believe related) issues. Firstly, I see the following error:
>>
>> [+] Selected device: TITAN X (Pascal)
>> [!] CL Error (-30, /home/user/gr-fosphor/lib/fosphor/cl.c:409): Unable to
>> queue clear of spectrum buffer
>
> That's really weird indeed. Although I've seen it before. Can't
> remember exactly what it was though ...

Actually the reason I'm not seeing it anymore on my setup is because I
don't have any machine with CL/GL sharing working any more ... I
changed laptop since and I can't get CL/GL sharing working with
optirun and recent nvidia drivers ...

One thing I would point out though is that if you have CL/GL sharing
working, you can pretty much comment the entire call to
cl_queue_clear_buffers because the GL side of things will clear the
buffers already and they are the same. The independent clearing of the
CL buffers only matter if they're different.

I'll comment out that call for my purposes and let you know how that goes. My guess is that resolves the -30 error but not the blocky/pixelated spectrum histogram.


--
Raj Bhattacharjea, PhD
Georgia Tech Research Institute
Information and Communications Laboratory



--
Raj Bhattacharjea, PhD
Georgia Tech Research Institute
Information and Communications Laboratory
404.407.6622