[PATCH] retrace: support for dumping multiple snapshots

[Tapani Pälli]

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'.

Thanks;

// Tapani