Hello,
I have some questions related to development of video drivers:
Double buffered screen:
In the case where the system really provides 2 distinct video memory
spaces for the video buffers, when the call to SDL_Flip() is done: does
the video driver have to change the (SDL_Surface) videomode->pixels to
points to the correct video RAM ? This is what I do in the Atari Xbios
video driver, because it is the only way for the application to write in
the correct buffer. I did not see any info about this in the header files,
nor in the docs.
SDL as a backend for Mesa:
Mesa can use svgalib, ggi, x11 as drawing backends. SDL uses Mesa
functions to create OpenGL rendering contexts in some video drivers. Could
it be possible to write a SDL backend for Mesa ? And could it be possible
to use SDL with the same Mesa as an OpenGL video driver (is it clear ?):
I would like to setup a video mode with SDL, using Mesa as OpenGL driver,
and Mesa using same SDL to do OpenGL rendering on screen (see recursion there
?).
Screen with fixed size:
When you have a video output that has a fixed width, height and bpp; does
the video driver report that fixed dimensions, or only the part of it that
was asked by the _SetVideoMode() ? i.e. if I have a fixed 640x480
framebuffer, should the driver always report a 640x480 surface (and SDL
will take care of it), or a for example the smaller 320x240 or 400x300
asked surface ?
Thanks in advance for the meaningful answers.
PS: for Sam, did you receive my patches I sent you last week (mainly
related to Atari drivers)? I would like to see them applied.–
Patrice Mandin
WWW: http://membres.lycos.fr/pmandin/
Programmeur Linux, Atari
Sp?cialit?: D?veloppement, jeux
Hello,
I have some questions related to development of video drivers:
Double buffered screen:
In the case where the system really provides 2 distinct video memory
spaces for the video buffers, when the call to SDL_Flip() is done: does
the video driver have to change the (SDL_Surface) videomode->pixels to
points to the correct video RAM ? This is what I do in the Atari Xbios
video driver, because it is the only way for the application to write in
the correct buffer.
Yes, this is the correct method.
SDL as a backend for Mesa:
Mesa can use svgalib, ggi, x11 as drawing backends. SDL uses Mesa
functions to create OpenGL rendering contexts in some video drivers. Could
it be possible to write a SDL backend for Mesa ? And could it be possible
to use SDL with the same Mesa as an OpenGL video driver (is it clear ?):
I would like to setup a video mode with SDL, using Mesa as OpenGL driver,
and Mesa using same SDL to do OpenGL rendering on screen (see recursion there
?).
I don’t know if anybody has done it, but you might be able to hack it together.
Screen with fixed size:
When you have a video output that has a fixed width, height and bpp; does
the video driver report that fixed dimensions, or only the part of it that
was asked by the _SetVideoMode() ? i.e. if I have a fixed 640x480
framebuffer, should the driver always report a 640x480 surface (and SDL
will take care of it), or a for example the smaller 320x240 or 400x300
asked surface ?
Yes, report the fixed framebuffer size and SDL will center the video mode
presented to the application in the real fixed framebuffer.
PS: for Sam, did you receive my patches I sent you last week (mainly
related to Atari drivers)? I would like to see them applied.
No, I didn’t see them. Can you resend?
Thanks,
-Sam Lantinga, Software Engineer, Blizzard Entertainment
Dans l’article <mailman.1038987062.19735.sdl at libsdl.org>, “Sam Lantinga”
a tapot? avec ses petits doigts:
PS: for Sam, did you receive my patches I sent you last week (mainly
related to Atari drivers)? I would like to see them applied.
No, I didn’t see them. Can you resend?
I first sent them to slouken(at)libsdl(dot)org (on 11/26/2002), then I
resent them this time to slouken(at)devolution(dot)com (on 12/04/2002).
Maybe it should be useful to have a mail address to send patches to, like
patches(at)libsdl(dot)org.–
Patrice Mandin
WWW: http://membres.lycos.fr/pmandin/
Programmeur Linux, Atari
Sp?cialit?: D?veloppement, jeux