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view docs/html/guidecdromexamples.html @ 1544:ab1e4c41ab71
Fixed bug #33
Mike Frysinger wrote:
> with libsdl-1.2.9, some games (like bomberclone) started
> segfaulting in Gentoo
[...snip...]
> the last change in the last hunk:
[...snip...]
> if i change the statement to read:
> (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures()
> bomberclone no longer segfaults on my box
Alex Volkov wrote:
> The test "(table[which].blit_features & GetBlitFeatures()) ==
> table[which].blit_features)" is correct, and the previous
> "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken.
I think there is potentially a slightly different cause of the above problem.
During the introduction of the Altivec code, the blit_table struct field
'alpha' got changed from a straightforward enum to a bitmask, which makes
perfect sense by itself. However, now the table driven blitter selection code
in SDL_CalculateBlitN() can choose the wrong blitters when searching for a
NO_ALPHA blitter because of the following code:
int a_need = 0;
...
(a_need & table[which].alpha) == a_need &&
When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like
Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing
alpha channel bits to appear in a non-alpha destination surface. I suppose this
could theoretically be an indirect cause of the segfault mentioned above.
I *think* this can be fixed by changing to
int a_need = NO_ALPHA;
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 15 Mar 2006 15:47:49 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >CDROM Examples</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="Examples" HREF="guideexamples.html"><LINK REL="PREVIOUS" TITLE="Audio Examples" HREF="guideaudioexamples.html"><LINK REL="NEXT" TITLE="Time Examples" HREF="guidetimeexamples.html"></HEAD ><BODY CLASS="SECT1" 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="guideaudioexamples.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 4. Examples</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="guidetimeexamples.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="GUIDECDROMEXAMPLES" ></A >CDROM Examples</H1 ><P ></P ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN393" ></A >Listing CD-ROM drives</H2 ><P ><PRE CLASS="PROGRAMLISTING" > #include "SDL.h" /* Initialize SDL first */ if ( SDL_Init(SDL_INIT_CDROM) < 0 ) { fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError()); exit(1); } atexit(SDL_Quit); /* Find out how many CD-ROM drives are connected to the system */ printf("Drives available: %d\n", SDL_CDNumDrives()); for ( i=0; i<SDL_CDNumDrives(); ++i ) { printf("Drive %d: \"%s\"\n", i, SDL_CDName(i)); }</PRE ></P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN397" ></A >Opening the default drive</H2 ><P ><PRE CLASS="PROGRAMLISTING" > SDL_CD *cdrom; CDstatus status; char *status_str; cdrom = SDL_CDOpen(0); if ( cdrom == NULL ) { fprintf(stderr, "Couldn't open default CD-ROM drive: %s\n", SDL_GetError()); exit(2); } status = SDL_CDStatus(cdrom); switch (status) { case CD_TRAYEMPTY: status_str = "tray empty"; break; case CD_STOPPED: status_str = "stopped"; break; case CD_PLAYING: status_str = "playing"; break; case CD_PAUSED: status_str = "paused"; break; case CD_ERROR: status_str = "error state"; break; } printf("Drive status: %s\n", status_str); if ( status >= CD_PLAYING ) { int m, s, f; FRAMES_TO_MSF(cdrom->cur_frame, &m, &s, &f); printf("Currently playing track %d, %d:%2.2d\n", cdrom->track[cdrom->cur_track].id, m, s); }</PRE ></P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN401" ></A >Listing the tracks on a CD</H2 ><P ><PRE CLASS="PROGRAMLISTING" > SDL_CD *cdrom; /* Assuming this has already been set.. */ int i; int m, s, f; SDL_CDStatus(cdrom); printf("Drive tracks: %d\n", cdrom->numtracks); for ( i=0; i<cdrom->numtracks; ++i ) { FRAMES_TO_MSF(cdrom->track[i].length, &m, &s, &f); if ( f > 0 ) ++s; printf("\tTrack (index %d) %d: %d:%2.2d\n", i, cdrom->track[i].id, m, s); }</PRE ></P ></DIV ><DIV CLASS="SECT2" ><H2 CLASS="SECT2" ><A NAME="AEN405" ></A >Play an entire CD</H2 ><P ><PRE CLASS="PROGRAMLISTING" > SDL_CD *cdrom; /* Assuming this has already been set.. */ // Play entire CD: if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) SDL_CDPlayTracks(cdrom, 0, 0, 0, 0); // Play last track: if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) { SDL_CDPlayTracks(cdrom, cdrom->numtracks-1, 0, 0, 0); } // Play first and second track and 10 seconds of third track: if ( CD_INDRIVE(SDL_CDStatus(cdrom)) ) SDL_CDPlayTracks(cdrom, 0, 0, 2, CD_FPS * 10);</PRE ></P ></DIV ></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="guideaudioexamples.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="guidetimeexamples.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Audio Examples</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="guideexamples.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Time Examples</TD ></TR ></TABLE ></DIV ></BODY ></HTML >