view docs/html/sdlcdplaytracks.html @ 1259:36f24cdfcda7

te: Thu, 17 Apr 2003 11:25:26 -0700 From: "Jim" Subject: [SDL] Frame buffer patches... Would seem that GCC 3.2.2 promotes all signed values to unsigned if any single vlaue is unsigned in an expression... for instance when calculating an elo touch position....evertyhign is an (int) except for cach_vinfo.xres which is unsigned. THerefore if y ou reverse the SDL_ELO_MIN_X and SDL_ELO_MAX_X values the resulging negative value pegs the expression to it's max. Attached it the accumu lated patch to typecast the unsigned values to (int) - *dx = (cache_vinfo.xres - (cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); + *dx = ((int)cache_vinfo.xres - ((int)cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); and also to provide quite failure to operations which have the screen currently locked... The touch screen I'm using the original values were exactly opposite of any position I touched on the screen - evaluating the math the expr ession SHOULD have handled reversing the min and max values - and after casting the unsigned .xres and .yres to a signed int - worked well. .. Jim
author Sam Lantinga <slouken@libsdl.org>
date Tue, 24 Jan 2006 06:36:43 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>SDL_CDPlayTracks</TITLE
><META
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><H1
><A
NAME="SDLCDPLAYTRACKS"
></A
>SDL_CDPlayTracks</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN7375"
></A
><H2
>Name</H2
>SDL_CDPlayTracks&nbsp;--&nbsp;Play the given CD track(s)</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN7378"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN7379"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_CDPlayTracks</B
></CODE
>(SDL_CD *cdrom, int start_track, int start_frame, int ntracks, int nframes));</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7385"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_CDPlayTracks</TT
> plays the given CD starting at track
<TT
CLASS="PARAMETER"
><I
>start_track</I
></TT
>, for <TT
CLASS="PARAMETER"
><I
>ntracks</I
></TT
> tracks.  </P
><P
><TT
CLASS="PARAMETER"
><I
>start_frame</I
></TT
> is the frame offset, from the beginning of the <TT
CLASS="PARAMETER"
><I
>start_track</I
></TT
>, at which to start. <TT
CLASS="PARAMETER"
><I
>nframes</I
></TT
> is the frame offset, from the beginning of the last track (<TT
CLASS="PARAMETER"
><I
>start_track</I
></TT
>+<TT
CLASS="PARAMETER"
><I
>ntracks</I
></TT
>), at which to end playing.</P
><P
><TT
CLASS="FUNCTION"
>SDL_CDPlayTracks</TT
> should only be called after calling 
<A
HREF="sdlcdstatus.html"
><TT
CLASS="FUNCTION"
>SDL_CDStatus</TT
></A
> 
to get track information about the CD.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>Data tracks are ignored.</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7403"
></A
><H2
>Return Value</H2
><P
>Returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, or <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> 
if there was an error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN7408"
></A
><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>/* 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);</PRE
>
&#13;</P
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><H2
>See Also</H2
><P
><A
HREF="sdlcdplay.html"
><TT
CLASS="FUNCTION"
>SDL_CDPlay</TT
></A
>,
<A
HREF="sdlcdstatus.html"
><TT
CLASS="FUNCTION"
>SDL_CDStatus</TT
></A
>,
<A
HREF="sdlcd.html"
><TT
CLASS="FUNCTION"
>SDL_CD</TT
></A
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