Mercurial > sdl-ios-xcode
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 |
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.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