How can I scale the display with glSDL?

SDL Development
1

I’m doing digital video at 15fps.

I need to scale the display window without loading the CPU. I have a 640x240
image buffer that I want to stretch to 1280x960 on the screen. I don’t like
the quality hit from using the YUV overlay method.

I keep reading that accelerated display scaling is possible with glSDL, but I
don’t understand how to do it. Anyone know the answer?

Thanks!

2

In some versions of glSDL/wrapper, there is a feature that scales
anything below 640x480 to 640x480 or higher. 320x240 is scaled to
640x480, 400x300 is scaled to 800x600 etc.

There is an API extension for generic scaling as well, but I think
it’s broken… I’ve never actually used it, and I haven’t tested it
since early versions.

//David Olofson - Programmer, Composer, Open Source Advocate

.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,… |
`-----------------------------------> http://audiality.org -’
— http://olofson.net — http://www.reologica.se —On Friday 05 November 2004 07.20, Matt Wheeler wrote:

I’m doing digital video at 15fps.

I need to scale the display window without loading the CPU. I have
a 640x240 image buffer that I want to stretch to 1280x960 on the
screen. I don’t like the quality hit from using the YUV overlay
method.

I keep reading that accelerated display scaling is possible with
glSDL, but I don’t understand how to do it. Anyone know the answer?

3

In some versions of glSDL/wrapper, there is a feature that scales…

How is this scalling controlled in glSDL? I guess I’m not understaning the API.

4

It isn’t, really. What happens is that if you ask for a “screen” size
smaller than 640x480, glSDL will set up a bigger (higher resolution)
display at 640x480 or higher, and set up OpenGL to do the scaling.

There are, however, a few inherent implementation issues with this,
which is why it has been removed in the last version of
glSDL/wrapper, and it will not be in the glSDL backend.

//David Olofson - Programmer, Composer, Open Source Advocate

.- Audiality -----------------------------------------------.
| Free/Open Source audio engine for games and multimedia. |
| MIDI, modular synthesis, real time effects, scripting,… |
`-----------------------------------> http://audiality.org -’
— http://olofson.net — http://www.reologica.se —On Friday 05 November 2004 20.23, Matt Wheeler wrote:

In some versions of glSDL/wrapper, there is a feature that
scales…

How is this scalling controlled in glSDL? I guess I’m not
understaning the API.