Updated DIB Engine

[Roderick Colenbrander]

> 2009/1/25 Massimo Del Fedele <max at veneto.com>:
> > The engine is disabled by default; can be changed by environment
> variable :
> >
> > export WINEDIB=ON (or ENABLE or ENABLED or TRUE)  enables it
> > export WINEDIB=OFF (or DISABLE or DISABLED or FALSE)  disables it
> >
> > or by registry key :
> >
> > HKCU/Software/Wine/DIB Engine/Enable='Y'  enables it
> > HKCU/Software/Wine/DIB Engine/Enable='N'  disables it
> >
> > the environment variable has precedence on registry, so for example if
> > WINEDIB=ON and HKCU/Software/Wine/DIB Engine/Enable='N' the engine is
> > enabled.
> >
> > I suggest to use the environment for the moment, at less you have an app
> > that runs much better with the engine (autocad, for example...) which
> > benefits from a default enabled engine in registry.
> 
> I'm still opposed to adding an environment variable for something so
> simple (an enable/disable flag). It just seems like extra work for no
> benefit to me. I'm sure we can all agree that the registry is a
> suitable place for the setting.
> 
> Isn't the idea that the DIB engine will only be used as needed, and
> will be good in all cases where it's used? If that's the case, it's
> not too important having on-the-fly per-application enabling/disabling
> (whereas WINEDEBUG and WINEDLLOVERRIDES can be VERY useful).
> 

Having an environment variable is a minor detail. Sure it should be used transparently but it will take a lot of time (when the architecture is correct) to enable it by default. A lot of performance tuning would be needed as it could seriously decrease performance in a lot of cases. The gain / loss depends on what type of calls the program is making. If it draws lets say on a line by line basis then software rendering could help. But if it uses a smarter method a single X call might be more efficient. Further there are also other tradeoffs e.g. when the latest version of the drawable is in X then it might not be smart at all to copy it back to the DIB engine and let it do the rendering just because we have a DIB engine. The cost for the download and reupload to the videocard might be much higher.

Roderick
-- 
NUR NOCH BIS 31.01.! GMX FreeDSL - Telefonanschluss + DSL 
für nur 16,37 EURO/mtl.!* http://dsl.gmx.de/?ac=OM.AD.PD003K11308T4569a