DirectDraw over Direct3D

[Roderick Colenbrander]

Hi,

> Is Starcraft really that slow?   How does this compare with using DGA?
>  I'm not too sure because its speed vaires.  I've been testing
> Starcraft this weekend and it has been plenty speedy.   But I do
> remember when trying to play it multiplayer a few months ago and was
> burned when it ran slow.  In fact it slowed *everyone* down.  Not fun.

Atleast on my system StarCraft was really unplayable while the game is
supposed to run on a 20x slower system (pentium90). Perhaps the problem is
video driver related as I think the issues are less severe for Ati users.
(thought I heard this but not sure)

> 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?

The code won't work for cards without hw accelerated opengl but note that
most cards these days have opengl support. A simple Riva TNT is already
quite old but is still supported on Linux and it should do a fine job only
it can't handle the palette conversion. I haven't tested performance much
using Mesa, I could try that soon using some games but it doesn't have to be
slower than the current code as Mesa uses Xlib too in the indirect case. In
general about all cards these days have some form of opengl support (intel,
via, ati, nvidia, ..) perhaps only the latest S3 GPUs and perhaps some sis
ones (thought some have drivers) lack support. Note that cards don't need
much functionality at all as OpenGL is only for the uploading of textures
and the rendering of them.

I think the patch is a reasonable solution to work around various depth
conversion problems. For sure it is the fastest way for the conversion as
the videocard basicly does it for free. On my system StarCraft and the
Command&Conquer series (although they crash quite quickly due to threading
issues) felt a lot faster, I think that the speed is close to that of DGA.

Roderick

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