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view docs/html/sdlgetkeystate.html @ 968:4675910b0b7b
Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST)
From: Hannu Savolainen
Subject: Re: SDL uses obsolete OSS features
I did some work on getting OSS to work better with SDL. There have been
some problems with select which should be fixed now.
I'm having some problems in understanding what is the purpose of the
DSP_WaitAudio() routine. I added a return to the very beginning of this
routine and commendted out the define for USE_BLOCKING_WRITES. At least
lbreakout2 seems to work as well as earlier. The latencies are the same.
An ordinary blocking write does exactly the same thing than DSP_WaitAudio
does. So I would recommend using the USE_BLOCKING_WRITES approach and
removing everything from the DSP_WaitAudio routine. Also enabling
USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because
you don't need to handle the partial writes (the do-while loop).
Attached is a patch against SDL-1.2.7. After these changes SDL will use
OSS as it's designed to be used (make it as simple as possible). This code
should work with all OSS implementations because it uses only the very
fundamental features that have been there since the jurassic times.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Fri, 12 Nov 2004 21:39:04 +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 >