Mercurial > sdl-ios-xcode
view docs/man3/SDL_CDtrack.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_CDtrack" "3" "Tue 11 Sep 2001, 22:59" "SDL" "SDL API Reference" .SH "NAME" SDL_CDtrack\- CD Track Information Structure .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct{ Uint8 id; Uint8 type; Uint32 length; Uint32 offset; } SDL_CDtrack;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBid\fR Track number (0-99) .TP 20 \fBtype\fR \fBSDL_AUDIO_TRACK\fP or \fBSDL_DATA_TRACK\fP .TP 20 \fBlength\fR Length, in frames, of this track .TP 20 \fBoffset\fR Frame offset to the beginning of this track .SH "DESCRIPTION" .PP \fBSDL_CDtrack\fR stores data on each track on a CD, its fields should be pretty self explainatory\&. It is a member a the \fI\fBSDL_CD\fR\fR structure\&. .PP .RS \fBNote: .PP Frames can be converted to standard timings\&. There are \fBCD_FPS\fP frames per second, so \fBSDL_CDtrack\fR\&.\fBlength\fR/\fBCD_FPS\fP=length_in_seconds\&. .RE .SH "SEE ALSO" .PP \fI\fBSDL_CD\fR\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:59