view docs/man3/SDL_CDPlayTracks.3 @ 1542:a8bf1aa21020

Fixed bug #15 SDL_blit_A.mmx-speed.patch.txt -- Speed improvements and a bugfix for the current GCC inline mmx asm code: - Changed some ops and removed some resulting useless ones. - Added some instruction parallelism (some gain) The resulting speed on my Xeon improved upto 35% depending on the function (measured in fps). - Fixed a bug where BlitRGBtoRGBSurfaceAlphaMMX() was setting the alpha component on the destination surfaces (to opaque-alpha) even when the surface had none. SDL_blit_A.mmx-msvc.patch.txt -- MSVC mmx intrinsics version of the same GCC asm code. MSVC compiler tries to parallelize the code and to avoid register stalls, but does not always do a very good job. Per-surface blending MSVC functions run quite a bit faster than their pure-asm counterparts (upto 55% faster for 16bit ones), but the per-pixel blending runs somewhat slower than asm. - BlitRGBtoRGBSurfaceAlphaMMX and BlitRGBtoRGBPixelAlphaMMX (and all variants) can now also handle formats other than (A)RGB8888. Formats like RGBA8888 and some quite exotic ones are allowed -- like RAGB8888, or actually anything having channels aligned on 8bit boundary and full 8bit alpha (for per-pixel alpha blending). The performance cost of this change is virtually 0 for per-surface alpha blending (no extra ops inside the loop) and a single non-MMX op inside the loop for per-pixel blending. In testing, the per-pixel alpha blending takes a ~2% performance hit, but it still runs much faster than the current code in CVS. If necessary, a separate function with this functionality can be made. This code requires Processor Pack for VC6.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 15 Mar 2006 15:39:29 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_CDPlayTracks" "3" "Tue 11 Sep 2001, 22:58" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_CDPlayTracks\- Play the given CD track(s)
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_CDPlayTracks\fP\fR(\fBSDL_CD *cdrom, int start_track, int start_frame, int ntracks, int nframes)\fR);
.SH "DESCRIPTION"
.PP
\fBSDL_CDPlayTracks\fP plays the given CD starting at track \fBstart_track\fR, for \fBntracks\fR tracks\&. 
.PP
\fBstart_frame\fR is the frame offset, from the beginning of the \fBstart_track\fR, at which to start\&. \fBnframes\fR is the frame offset, from the beginning of the last track (\fBstart_track\fR+\fBntracks\fR), at which to end playing\&.
.PP
\fBSDL_CDPlayTracks\fP should only be called after calling \fI\fBSDL_CDStatus\fP\fR to get track information about the CD\&.
.PP
.RS
\fBNote:  
.PP
Data tracks are ignored\&.
.RE
.SH "RETURN VALUE"
.PP
Returns \fB0\fR, or \fB-1\fR if there was an error\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CW/* assuming cdrom is a previously opened device */
/* Play the entire CD */
if(CD_INDRIVE(SDL_CDStatus(cdrom)))
  SDL_CDPlayTracks(cdrom, 0, 0, 0, 0);

/* Play the first track */
if(CD_INDRIVE(SDL_CDStatus(cdrom)))
  SDL_CDPlayTracks(cdrom, 0, 0, 1, 0);

/* Play first 15 seconds of the 2nd track */
if(CD_INDRIVE(SDL_CDStatus(cdrom)))
  SDL_CDPlayTracks(cdrom, 1, 0, 0, CD_FPS*15);\fR
.fi
.PP
 
.SH "SEE ALSO"
.PP
\fI\fBSDL_CDPlay\fP\fR, \fI\fBSDL_CDStatus\fP\fR, \fI\fBSDL_CD\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:58