Mercurial > sdl-ios-xcode
view docs/html/sdlgetkeystate.html @ 3880:74e828c64315 SDL-1.2
Fixed bug #292
I might be on crack here.
It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and
right channels of a stereo stream together, and clamps the new mono channel if
it would overflow.
Shouldn't it be dividing by 2 to average the two sample points instead of
clamping? Otherwise the mono sample point's volume doubles in the conversion.
This would also make the conversion faster, as it replaces two branches per
sample frame with a bitwise shift.
--ryan.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 24 Sep 2006 15:45:37 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_GetKeyState</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="Event Functions." HREF="eventfunctions.html"><LINK REL="PREVIOUS" TITLE="SDL_EventState" HREF="sdleventstate.html"><LINK REL="NEXT" TITLE="SDL_GetModState" HREF="sdlgetmodstate.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="sdleventstate.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlgetmodstate.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLGETKEYSTATE" ></A >SDL_GetKeyState</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN5686" ></A ><H2 >Name</H2 >SDL_GetKeyState -- Get a snapshot of the current keyboard state</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN5689" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN5690" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >Uint8 *<B CLASS="FSFUNC" >SDL_GetKeyState</B ></CODE >(int *numkeys);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN5696" ></A ><H2 >Description</H2 ><P >Gets a snapshot of the current keyboard state. The current state is return as a pointer to an array, the size of this array is stored in <TT CLASS="PARAMETER" ><I >numkeys</I ></TT >. The array is indexed by the <A HREF="sdlkey.html" ><TT CLASS="LITERAL" >SDLK_*</TT ></A > symbols. A value of 1 means the key is pressed and a value of 0 means its not. The pointer returned is a pointer to an internal SDL array and should not be freed by the caller.</P ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B >Use <A HREF="sdlpumpevents.html" ><TT CLASS="FUNCTION" >SDL_PumpEvents</TT ></A > to update the state array.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN5706" ></A ><H2 >Example</H2 ><P ><PRE CLASS="PROGRAMLISTING" >Uint8 *keystate = SDL_GetKeyState(NULL); if ( keystate[SDLK_RETURN] ) printf("Return Key Pressed.\n");</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN5710" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlkey.html" ><TT CLASS="LITERAL" >SDL Key Symbols</TT ></A >, <A HREF="sdlpumpevents.html" ><TT CLASS="FUNCTION" >SDL_PumpEvents</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="sdleventstate.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="sdlgetmodstate.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_EventState</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="eventfunctions.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_GetModState</TD ></TR ></TABLE ></DIV ></BODY ></HTML >