view docs/man3/SDL_WasInit.3 @ 689:5bb080d35049

Date: Tue, 19 Aug 2003 17:57:00 +0200 From: Stephane Marchesin Subject: Re: [SDL] [patch] MMX alpha blit patches with MMX detection I think everything is correct now. I've done as much testing as I could, but some real-world testing wouldn't hurt, I think. The patch is here : http://icps.u-strasbg.fr/~marchesin/sdl_mmxblit.patch If you do byte-by-byte comparison of the output between C and MMX functions, you'll notice that the results for 555 and 565 RGB alpha blits aren't exactly the same. This is because MMX functions for 555 and 565 RGB have an higher accuracy. If you want the exact same behaviour that's possible by masking the three lower alpha bits in the MMX functions. Just ask ! I removed one MMX function because after I fixed it to match its C equivalent, it revealed to be slower than the C version on a PIII (although a bit faster on an Athlon XP). I've also added MMX and PIII replacements for SDL_memcpy. Those provide some speed up in testvidinfo -benchmark (at least for me, under linux & X11).
author Sam Lantinga <slouken@libsdl.org>
date Fri, 22 Aug 2003 05:51:19 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_WasInit" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_WasInit\- Check which subsystems are initialized
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBUint32 \fBSDL_WasInit\fP\fR(\fBUint32 flags\fR);
.SH "DESCRIPTION"
.PP
\fBSDL_WasInit\fP allows you to see which SDL subsytems have been \fIinitialized\fR\&. \fBflags\fR is a bitwise OR\&'d combination of the subsystems you wish to check (see \fI\fBSDL_Init\fP\fR for a list of subsystem flags)\&.
.SH "RETURN VALUE"
.PP
\fBSDL_WasInit\fP returns a bitwised OR\&'d combination of the initialized subsystems\&.
.SH "EXAMPLES"
.PP
.nf
\f(CW
/* Here are several ways you can use SDL_WasInit() */

/* Get init data on all the subsystems */
Uint32 subsystem_init;

subsystem_init=SDL_WasInit(SDL_INIT_EVERYTHING);

if(subsystem_init&SDL_INIT_VIDEO)
  printf("Video is initialized\&.
");
else
  printf("Video is not initialized\&.
");



/* Just check for one specfic subsystem */

if(SDL_WasInit(SDL_INIT_VIDEO)!=0)
  printf("Video is initialized\&.
");
else
  printf("Video is not initialized\&.
");




/* Check for two subsystems */

Uint32 subsystem_mask=SDL_INIT_VIDEO|SDL_INIT_AUDIO;

if(SDL_WasInit(subsystem_mask)==subsystem_mask)
  printf("Video and Audio initialized\&.
");
else
  printf("Video and Audio not initialized\&.
");
\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_Init\fP\fR, \fI\fBSDL_Subsystem\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00