Re: DirectDraw over Direct3D

[Roderick Colenbrander]

> This patch seems similar to glSDL where it wraps SDL's 2d API to
> OpenGL. The good thing about this it can provide acceleration and not
> require root like DGA.  The bad thing with this idea is that it can't
> be used on older video cards or even some newer ones that lack proper
> direct rendering.  Am I correct that even when just doing depth
> conversions, without direct rendering it will still be slow?

Perhaps I should clarify some misunderstandings that some people have. (I
hope I explain it correctly) Basicly DirectDraw provides a mechanism to
directly access the framebuffer of the videocard. This is the fastest way to
render 2D images on the screen. Games like StarCraft, Total Annihilation,
C&C and lots of others use DirectDraw in this way. Second there's another
class of games like Age Of Empires2, Heroes of Might and Magic IV and others
which mix ddraw with GDI. They for instance render a image using ddraw and
then use GetDC/ReleaseDC to get a device context so that they can draw in
the surface. (directly into the video memory)

In case of X direct framebuffer access is only possible through DGA but it
is unsecure and has other issues. When DGA works correctly it can accelerate
games like StarCraft. Further DGA doesn't have any depth conversion issues
as it does depth switching. Without DGA the rendering operations need to go
through X. Because of limitations of X, depth conversion problems appear
when the depth of the desktop and X aren't the same.

For depth conversion purposes Wine's DirectDraw uses a DIB section. Basicly
all pixels of an image are translated to the depth of X. This is slow and
especially for the case when the application requests 8bit paletted mode
using a 24bit desktop. In this case a color lookup needs to happen in a
palette for each pixel. The end result is then shown on the screen (if the
game is of the StarCraft type)

Games that use GetDC/ReleaseDC can't work using DGA. The performance in
general isn't great as lots of X calls happen. (things like conversions from
XPixmap to XImages and the way around and also depth conversions happen a
lot)

The patch I sent works for both classes of games though it won't help much
for the second class as GetDC/ReleaseDC stuff is slow. As explained before
the patch uploads the surface to a texture which is then rendered using
OpenGL. This is quite fast and as a bonus the videocard can do all depth
conversion for us as it isn't limited to rendering textures which are at the
same depth as X.

For old videocards the GL renderer won't work and the old code should work
fine (except for performance issues). You might have heard people talking
about a 'dibengine' which would let Wine do all DIB related operations in
software which would save a lot of XImage/XPixmap conversions. (conversion
is only needed for the final rendering stage) This dibengine would mainly
accelerate games that use GetDC/ReleaseDC. It won't help games like
StarCraft (much) as for those DIBs were only used for depth conversion and
the conversion algorithm stays the same (it can't be tweaked much if at
all). So there's not really a way to speedup games like StarCraft for old
videocards. Perhaps XShm might be of use but not sure how much it would
help. (think it would only be usefull for GetDC/ReleaseDC games)

Roderick

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DirectDraw over Direct3D

[Molle Bestefich]

Roderick Colenbrander wrote:
> For old videocards the GL renderer won't work and the

The current state of open source video drivers for Linux is as far as
I know that they only do basic 2D.  For 3D you have to use
closed-source drivers, which is simply not an option for a lot of
people, be that because of stability, compatability or other issues.

Which means that your patch only helps the select few that are using
closed-source video drivers, is that correct?

For everybody else, your patch will mean a tremendous slowdown
instead, is that correct?
> old code should work fine (except for performance issues).

I've never had a performance issue with Starcraft under (recent) Wine,
so I don't think improving Starcraft performance is a very good
argument.  Better to promote other apps from
http://appdb.winehq.org/votestats.php that actually run sluggish? 
Just MHO.

That said, I *will* test your patch when I get home ;-).

DirectDraw over Direct3D

[Jesse Allen]

On 12/15/05, Molle Bestefich <molle.bestefich(a)gmail.com> wrote:
> Roderick Colenbrander wrote:
> > For old videocards the GL renderer won't work and the
>
> The current state of open source video drivers for Linux is as far as
> I know that they only do basic 2D.  For 3D you have to use
> closed-source drivers, which is simply not an option for a lot of
> people, be that because of stability, compatability or other issues.
>
> Which means that your patch only helps the select few that are using
> closed-source video drivers, is that correct?
>
> For everybody else, your patch will mean a tremendous slowdown
> instead, is that correct?

I have 3D acceleration in open source using DRI.  This patch will help us too.
> > old code should work fine (except for performance issues).
>
> I've never had a performance issue with Starcraft under (recent) Wine,
> so I don't think improving Starcraft performance is a very good
> argument.  Better to promote other apps from
> http://appdb.winehq.org/votestats.php that actually run sluggish?
> Just MHO.
>
> That said, I *will* test your patch when I get home ;-).

Both computers have gotten faster and Wine has probably improved in
performance (Like in Dsound) to make Starcraft faster.  Even though
Starcraft has gotten faster, technically, Starcraft still has the
software depth conversion bottleneck.  It will continue to be like
this until we get rootless DGA or OpenGL handles the 2D.

That said, it does seem that most other 2D games I've tried seem
sluggish besides Starcraft.

DirectDraw over Direct3D

[Molle Bestefich]

Jesse Allen wrote:
> > The current state of open source video drivers for Linux is as far as
> > I know that they only do basic 2D.  For 3D you have to use
> > closed-source drivers, which is simply not an option for a lot of
> > people, be that because of stability, compatability or other issues.
> >
> > Which means that your patch only helps the select few that are using
> > closed-source video drivers, is that correct?
> >
> > For everybody else, your patch will mean a tremendous slowdown
> > instead, is that correct?
>
> I have 3D acceleration in open source using DRI.  This patch will help us too.

I wonder who "us" is :-).  What hardware do you have?

I've got ATI and the fglrx driver works like fixing a wristclock with
a large brick works.  Not good.  So I'm on the open source wagon.  I
imagine that lots of other people are using OS drivers too.  Does
anyone have a good overview of how many of the more popular OS video
drivers actually implement enough 3D for the patch to be a Good Thing?

The patch is fine and all, but if I'm right and there's a lot of
people using OS drivers that doesn't support the features needed (thus
making performance worse), this patch should be optional and not
replace the current working stuff..

.02 €/£/$/¥

DirectDraw over Direct3D

[Jesse Allen]

On 12/15/05, Molle Bestefich <molle.bestefich(a)gmail.com> wrote:
> Jesse Allen wrote:
> > > The current state of open source video drivers for Linux is as far as
> > > I know that they only do basic 2D.  For 3D you have to use
> > > closed-source drivers, which is simply not an option for a lot of
> > > people, be that because of stability, compatability or other issues.
> > >
> > > Which means that your patch only helps the select few that are using
> > > closed-source video drivers, is that correct?
> > >
> > > For everybody else, your patch will mean a tremendous slowdown
> > > instead, is that correct?
> >
> > I have 3D acceleration in open source using DRI.  This patch will help us too.
>
> I wonder who "us" is :-).  What hardware do you have?
>
> I've got ATI and the fglrx driver works like fixing a wristclock with
> a large brick works.  Not good.  So I'm on the open source wagon.  I
> imagine that lots of other people are using OS drivers too.  Does
> anyone have a good overview of how many of the more popular OS video
> drivers actually implement enough 3D for the patch to be a Good Thing?

I have Radeon 9200, using the r200 driver from dri.sourceforge.net. 
The r200 is good enough to play most all games.  r300 works I hear,
but not on my IGP X300.  I do think OS drivers are the way to go so I
hope to help the r300 project out in the the future.

I have no idea on fglrx, never used and don't plan to.
> The patch is fine and all, but if I'm right and there's a lot of
> people using OS drivers that doesn't support the features needed (thus
> making performance worse), this patch should be optional and not
> replace the current working stuff..
>
> .02 €/£/$/¥

I dunno, it is a legitimate complaint, but it is optional.  I think
the patch requires a registry setting to activate the Opengl depth
conversion stuff.

DirectDraw over Direct3D

[Peter Beutner]

Molle Bestefich schrieb:
> The patch is fine and all, but if I'm right and there's a lot of
> people using OS drivers that doesn't support the features needed (thus
> making performance worse), this patch should be optional and not
> replace the current working stuff..
> as far as I understood it this patch has no drawback for users without the needed OpenGL 
> features. If your driver supports them, fine and things will speed up.
> Otherwise it's done the same way like before(with the same performance).
> .02 €/£/$/¥
>
> ------------------------------------------------------------------------

DirectDraw over Direct3D

[Roderick Colenbrander]

> --- Ursprüngliche Nachricht ---
> Von: Molle Bestefich <molle.bestefich(a)gmail.com>
> An: Jesse Allen <the3dfxdude(a)gmail.com>
> Kopie: Roderick Colenbrander <thunderbird2k(a)gmx.net>,
> wine-devel(a)winehq.org
> Betreff: Re: DirectDraw over Direct3D
> Datum: Thu, 15 Dec 2005 20:03:32 +0100
>
> Jesse Allen wrote:
> > > The current state of open source video drivers for Linux is as far as
> > > I know that they only do basic 2D.  For 3D you have to use
> > > closed-source drivers, which is simply not an option for a lot of
> > > people, be that because of stability, compatability or other issues.
> > >
> > > Which means that your patch only helps the select few that are using
> > > closed-source video drivers, is that correct?
> > >
> > > For everybody else, your patch will mean a tremendous slowdown
> > > instead, is that correct?
> >
> > I have 3D acceleration in open source using DRI.  This patch will help
> > us too.
>
> I wonder who "us" is :-).  What hardware do you have?
>
> I've got ATI and the fglrx driver works like fixing a wristclock with
> a large brick works.  Not good.  So I'm on the open source wagon.  I
> imagine that lots of other people are using OS drivers too.  Does
> anyone have a good overview of how many of the more popular OS video
> drivers actually implement enough 3D for the patch to be a Good Thing?
>
> The patch is fine and all, but if I'm right and there's a lot of
> people using OS drivers that doesn't support the features needed (thus
> making performance worse), this patch should be optional and not
> replace the current working stuff..
>
> .02 €/£/$/¥

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