view docs/html/sdlkeysym.html @ 3096:ae4e80dbe330

Date: Tue, 17 Feb 2009 14:00:25 +0100 From: Stefan Klug Subject: [SDL] Possible bug, paused audio playing garbage On my WinCE device a paused audio device plays random garbage. This might also be the issue in the thread "sound cracks with SDL_mixer and AUDIO_S16LSB" I don't have that much knowledge of the SDL audio part, but the attached patch fixes it for me, and collapses two redundant ifs. I'm not sure if this is the correct way to fix this. Shouldn't the complete stream conversion part of the RunAudio loop be dependent on the paused property of the device? (not only the call to (*fill)(udata, istream, istream_len). Anyways. Would be great if the patch or a fix could find its way to SVN ;-) Cheers Stefan
author Sam Lantinga <slouken@libsdl.org>
date Mon, 23 Mar 2009 05:21:40 +0000
parents 355632dca928
children
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<HTML
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>SDL_keysym</TITLE
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><H1
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>SDL_keysym</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4659"
></A
><H2
>Name</H2
>SDL_keysym&nbsp;--&nbsp;Keysym structure</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4662"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct{
  Uint8 scancode;
  SDLKey sym;
  SDLMod mod;
  Uint16 unicode;
} SDL_keysym;</PRE
></DIV
><DIV
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><H2
>Structure Data</H2
><DIV
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><TABLE
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><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>scancode</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Hardware specific scancode</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>sym</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>SDL virtual keysym</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>mod</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Current key modifiers</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>unicode</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Translated character</TD
></TR
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><P
></P
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CLASS="REFSECT1"
><A
NAME="AEN4686"
></A
><H2
>Description</H2
><P
>The <SPAN
CLASS="STRUCTNAME"
>SDL_keysym</SPAN
> structure is used by reporting key presses and releases since it is a part of the <A
HREF="sdlkeyboardevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_KeyboardEvent</SPAN
></A
>.</P
><P
>The <TT
CLASS="STRUCTFIELD"
><I
>scancode</I
></TT
> field should generally be left alone, it is the hardware dependent scancode returned by the keyboard. The <TT
CLASS="STRUCTFIELD"
><I
>sym</I
></TT
> field is extremely useful. It is the SDL-defined value of the key (see <A
HREF="sdlkey.html"
>SDL Key Syms</A
>. This field is very useful when you are checking for certain key presses, like so:
<PRE
CLASS="PROGRAMLISTING"
>.
.
while(SDL_PollEvent(&#38;event)){
  switch(event.type){
    case SDL_KEYDOWN:
      if(event.key.keysym.sym==SDLK_LEFT)
        move_left();
      break;
    .
    .
    .
  }
}
.
.</PRE
>
<TT
CLASS="STRUCTFIELD"
><I
>mod</I
></TT
> stores the current state of the keyboard modifiers as explained in <A
HREF="sdlgetmodstate.html"
><TT
CLASS="FUNCTION"
>SDL_GetModState</TT
></A
>. The <TT
CLASS="STRUCTFIELD"
><I
>unicode</I
></TT
> is only used when UNICODE translation is enabled with <A
HREF="sdlenableunicode.html"
><TT
CLASS="FUNCTION"
>SDL_EnableUNICODE</TT
></A
>. If <TT
CLASS="STRUCTFIELD"
><I
>unicode</I
></TT
> is non-zero then this a the UNICODE character corresponding to the keypress. If the high 9 bits of the character are 0, then this maps to the equivalent ASCII character:
<PRE
CLASS="PROGRAMLISTING"
>char ch;
if ( (keysym.unicode &#38; 0xFF80) == 0 ) {
  ch = keysym.unicode &#38; 0x7F;
}
else {
  printf("An International Character.\n");
}</PRE
>
UNICODE translation does have a slight overhead so don't enable it unless its needed.</P
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>See Also</H2
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