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view docs/html/sdlcdopen.html @ 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 | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_CDOpen</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="CD-ROM" HREF="cdrom.html"><LINK REL="PREVIOUS" TITLE="SDL_CDName" HREF="sdlcdname.html"><LINK REL="NEXT" TITLE="SDL_CDStatus" HREF="sdlcdstatus.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlcdname.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlcdstatus.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCDOPEN" ></A >SDL_CDOpen</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN7274" ></A ><H2 >Name</H2 >SDL_CDOpen -- Opens a CD-ROM drive for access.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN7277" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN7278" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_CD *<B CLASS="FSFUNC" >SDL_CDOpen</B ></CODE >(int drive);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7284" ></A ><H2 >Description</H2 ><P >Opens a CD-ROM drive for access. It returns a <A HREF="sdlcd.html" ><SPAN CLASS="STRUCTNAME" >SDL_CD</SPAN ></A > structure on success, or <TT CLASS="LITERAL" >NULL</TT > if the drive was invalid or busy. This newly opened CD-ROM becomes the default CD used when other CD functions are passed a <TT CLASS="LITERAL" >NULL</TT > CD-ROM handle. </P ><P >Drives are numbered starting with 0. Drive 0 is the system default CD-ROM.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7292" ></A ><H2 >Examples</H2 ><PRE CLASS="PROGRAMLISTING" >SDL_CD *cdrom; int cur_track; int min, sec, frame; SDL_Init(SDL_INIT_CDROM); atexit(SDL_Quit); /* Check for CD drives */ if(!SDL_CDNumDrives()){ /* None found */ fprintf(stderr, "No CDROM devices available\n"); exit(-1); } /* Open the default drive */ cdrom=SDL_CDOpen(0); /* Did if open? Check if cdrom is NULL */ if(!cdrom){ fprintf(stderr, "Couldn't open drive: %s\n", SDL_GetError()); exit(-1); } /* Print Volume info */ printf("Name: %s\n", SDL_CDName(0)); printf("Tracks: %d\n", cdrom->numtracks); for(cur_track=0;cur_track < cdrom->numtracks; cur_track++){ FRAMES_TO_MSF(cdrom->track[cur_track].length, &min, &sec, &frame); printf("\tTrack %d: Length %d:%d\n", cur_track, min, sec); } SDL_CDClose(cdrom);</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN7295" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcd.html" ><SPAN CLASS="STRUCTNAME" >SDL_CD</SPAN ></A >, <A HREF="sdlcdtrack.html" ><SPAN CLASS="STRUCTNAME" >SDL_CDtrack</SPAN ></A >, <A HREF="sdlcdclose.html" ><TT CLASS="FUNCTION" >SDL_CDClose</TT ></A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlcdname.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlcdstatus.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_CDName</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="cdrom.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_CDStatus</TD ></TR ></TABLE ></DIV ></BODY ></HTML >