[PATCH] retrace: support for dumping multiple snapshots

[Rob Clark]

On Fri, Jan 20, 2017 at 5:24 AM, Tapani Pälli <tapani.palli at intel.com> wrote:
> Hi;
>
> On 01/18/2017 01:43 AM, Rob Clark wrote:
>>
>> Usually if an app is using MRT, we want to dump (and diff) *all* the
>> render targets to track down where things are going wrong.
>>
>> Only implemented for GLDumper, since I don't know anything about D3D.
>>
>> TODO maybe cmdline arg to control this?  I'm not sure, I kinda tend to
>> think if you are using dump-images + diff-images you probably want to
>> compare all the render targets.  Maybe even depth/stencil.
>
>
> This seemed interesting idea to debug MRT so I tried this patch to trace
> test app that utilizes MRT but I did not get many dumps as result (was
> expecting dump of each buffer in gbuffer), just lots of files with '_0' like
> there was only 1 attachment in use.
>
> I believe this is because the app does additional processing steps after
> producing the gbuffer results and in the final render to display we do have
> only one buffer. How should this work, when does the dump happen from GL API
> POV? It seems likely that many games will have postprocess steps where
> gbuffer is already 'composited'.

fwiw, you probably need to use it w/ --calls "X-Y/draw".. by default
you'll only get the dumps on frame (when the gbuffer's aren't bound as
a MRT).

The use-case I had was dissecting a single frame's worth of draws to
find where things started going badly.  I think I may end up needing
to add depth/stencil buffer too.

BR,
-R


> Thanks;
>
> // Tapani