Mercurial > sdl-ios-xcode
view docs/html/sdlflip.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_Flip</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="Video" HREF="video.html"><LINK REL="PREVIOUS" TITLE="SDL_UpdateRects" HREF="sdlupdaterects.html"><LINK REL="NEXT" TITLE="SDL_SetColors" HREF="sdlsetcolors.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="sdlupdaterects.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlsetcolors.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLFLIP" ></A >SDL_Flip</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1426" ></A ><H2 >Name</H2 >SDL_Flip -- Swaps screen buffers</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1429" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN1430" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_Flip</B ></CODE >(SDL_Surface *screen);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1436" ></A ><H2 >Description</H2 ><P >On hardware that supports double-buffering, this function sets up a flip and returns. The hardware will wait for vertical retrace, and then swap video buffers before the next video surface blit or lock will return. On hardware that doesn't support double-buffering, this is equivalent to calling <A HREF="sdlupdaterect.html" >SDL_UpdateRect</A ><TT CLASS="PARAMETER" ><I >(screen, 0, 0, 0, 0)</I ></TT ></P ><P >The <TT CLASS="LITERAL" >SDL_DOUBLEBUF</TT > flag must have been passed to <A HREF="sdlsetvideomode.html" >SDL_SetVideoMode</A >, when setting the video mode for this function to perform hardware flipping.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1444" ></A ><H2 >Return Value</H2 ><P >This function returns <SPAN CLASS="RETURNVALUE" >0</SPAN > if successful, or <SPAN CLASS="RETURNVALUE" >-1</SPAN > if there was an error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1449" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlsetvideomode.html" ><TT CLASS="FUNCTION" >SDL_SetVideoMode</TT ></A >, <A HREF="sdlupdaterect.html" ><TT CLASS="FUNCTION" >SDL_UpdateRect</TT ></A >, <A HREF="sdlsurface.html" ><SPAN CLASS="STRUCTNAME" >SDL_Surface</SPAN ></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="sdlupdaterects.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="sdlsetcolors.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_UpdateRects</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_SetColors</TD ></TR ></TABLE ></DIV ></BODY ></HTML >