Re: OpenGL vs. SDL for 2D

["Vesselin Peev" <vesselinpeev@hotmail.com>]

Steve,

Thank you for the great information in general and the texture layout tips
in particular! I'll research the matter deeply, though ;-))
You said "push pixels hundreds of times faster than you can with
the CPU alone". I wonder why you say "with the CPU alone"
Isn't it that even a simple S3 Trio64 does 2D blitting through its own CPU
and relieves the burden on the main CPU?
So what you said still holds true l when you compare SDL on a GeForce2 and
OpenGL/Mesa on the same GeForce2, right?

Simple example: a plain blit/flip of a 800x600 screen

That's the last piece of the puzzle, and I think I made a decision already!

So why use SDL (without the OpenGL wrapping part) from now on then? It would
die out relatively quickly if this is the situation.

Is this the reason why your PLib skips over the SDL concept, too?

Long live OpenGL/Mesa! (Short live Microsoft patent pirates ;-)! )


----- Original Message -----
From: "Steve Baker" <sjbaker1@airmail.net>
To: <linuxgames@sunsite.dk>
Sent: Thursday, February 28, 2002 7:04 PM
Subject: Re: OpenGL vs. SDL for 2D


> > Vesselin Peev wrote:
>
> > I'd like to ask if it is possible to achieve better 2D performance
> > in plain sprite blitting by using OpenGL/Mesa instead of using SDL
> > on a decent 3D  graphics card?
>
> Yes...easily.  If you load your sprites as textures (preferably packing
> lots of them into large textures to avoid texture switching) and you'll
> be able to push pixels hundreds of times faster than you can with the CPU
> alone.  You'll get scaling, antialiasing, rotation and transparency for
free
> and you can also use the Z buffer to allow sprites to move behind
foreground
> layers without the need to worry about the rendering order.
>
> This is nice because at the same time as getting all of these speedups and
> quality improvements, your CPU is actually doing *LESS* work - so you have
> more time for AI, music, etc.
>
> > I know the inconvenience of using special dimensions for the sprites
under
> > OpenGL/DirectX...
>
> Not really.  For sprites, pack as many as you can into large maps.  The
large
> maps have to be even powers of two - but the sprites *within* the map can
be
> any size you like.  (Modern nVidia graphics cards can actually do
non-power-of-two
> maps too - although there are some restrictions, they shouldn't affect
sprites).
>
> > but it does not really matter these days, does it? Also, older hardware
> > would not be supported, but if a considerable performance boost is
possible,
> > that wouldn't matter, too.
>
> Indeed.  I think it's been a reasonable decision to presume the existance
of
> fast 3D hardware for at least a year now.  There will be some hold-outs
who
> still have antique hardware - but they won't seriously reduce the size of
your
> market.
>
> ----------------------------- Steve Baker -------------------------------
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