Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST) From: Hannu Savolainen Subject: Re: SDL uses obsolete OSS features I did some work on getting OSS to work better with SDL. There have been some problems with select which should be fixed now. I'm having some problems in understanding what is the purpose of the DSP_WaitAudio() routine. I added a return to the very beginning of this routine and commendted out the define for USE_BLOCKING_WRITES. At least lbreakout2 seems to work as well as earlier. The latencies are the same. An ordinary blocking write does exactly the same thing than DSP_WaitAudio does. So I would recommend using the USE_BLOCKING_WRITES approach and removing everything from the DSP_WaitAudio routine. Also enabling USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because you don't need to handle the partial writes (the do-while loop). Attached is a patch against SDL-1.2.7. After these changes SDL will use OSS as it's designed to be used (make it as simple as possible). This code should work with all OSS implementations because it uses only the very fundamental features that have been there since the jurassic times.

/* $XFree86: xc/include/extensions/Xinerama.h,v 3.2 2000/03/01 01:04:20 dawes Exp $ */

#ifndef _Xinerama_h
#define _Xinerama_h

#include "SDL_name.h"

typedef struct {
   int   screen_number;
   short x_org;
   short y_org;
   short width;
   short height;
} SDL_NAME(XineramaScreenInfo);

Bool SDL_NAME(XineramaQueryExtension) (
   Display *dpy,
   int     *event_base,
   int     *error_base
);

Status SDL_NAME(XineramaQueryVersion)(
   Display *dpy,
   int     *major,
   int     *minor
);

Bool SDL_NAME(XineramaIsActive)(Display *dpy);


/* 
   Returns the number of heads and a pointer to an array of
   structures describing the position and size of the individual
   heads.  Returns NULL and number = 0 if Xinerama is not active.
  
   Returned array should be freed with XFree().
*/

SDL_NAME(XineramaScreenInfo) * 
SDL_NAME(XineramaQueryScreens)(
   Display *dpy,
   int     *number
);

#endif /* _Xinerama_h */