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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
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.TH "SDL_UpdateRects" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_UpdateRects\- Makes sure the given list of rectangles is updated on the given screen\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBvoid \fBSDL_UpdateRects\fP\fR(\fBSDL_Surface *screen, int numrects, SDL_Rect *rects\fR);
.SH "DESCRIPTION"
.PP
Makes sure the given list of rectangles is updated on the given screen\&. The rectangles must all be confined within the screen boundaries (no clipping is done)\&.
.PP
This function should not be called while \fBscreen\fR is \fIlocked\fR\&.
.PP
.RS
\fBNote:  
.PP
It is adviced to call this function only once per frame, since each call has some processing overhead\&. This is no restriction since you can pass any number of rectangles each time\&.
.PP
The rectangles are not automatically merged or checked for overlap\&. In general, the programmer can use his knowledge about his particular rectangles to merge them in an efficient way, to avoid overdraw\&.
.RE
.SH "SEE ALSO"
.PP
\fI\fBSDL_UpdateRect\fP\fR, \fI\fBSDL_Rect\fR\fR, \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_LockSurface\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01