Mercurial > sdl-ios-xcode
view docs/html/sdlvideomodeok.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 |
line wrap: on
line source
<HTML ><HEAD ><TITLE >SDL_VideoModeOK</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_ListModes" HREF="sdllistmodes.html"><LINK REL="NEXT" TITLE="SDL_SetVideoMode" HREF="sdlsetvideomode.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="sdllistmodes.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlsetvideomode.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLVIDEOMODEOK" ></A >SDL_VideoModeOK</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1202" ></A ><H2 >Name</H2 >SDL_VideoModeOK -- Check to see if a particular video mode is supported.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1205" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN1206" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_VideoModeOK</B ></CODE >(int width, int height, int bpp, Uint32 flags);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1212" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_VideoModeOK</TT > returns <SPAN CLASS="RETURNVALUE" >0</SPAN > if the requested mode is not supported under any bit depth, or returns the bits-per-pixel of the closest available mode with the given width, height and requested <A HREF="sdlsurface.html" >surface</A > flags (see <A HREF="sdlsetvideomode.html" ><TT CLASS="FUNCTION" >SDL_SetVideoMode</TT ></A >).</P ><P >The bits-per-pixel value returned is only a suggested mode. You can usually request and bpp you want when <A HREF="sdlsetvideomode.html" >setting</A > the video mode and SDL will emulate that color depth with a shadow video surface.</P ><P >The arguments to <TT CLASS="FUNCTION" >SDL_VideoModeOK</TT > are the same ones you would pass to <A HREF="sdlsetvideomode.html" >SDL_SetVideoMode</A ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1225" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >SDL_Surface *screen; Uint32 bpp; . . . printf("Checking mode 640x480@16bpp.\n"); bpp=SDL_VideoModeOK(640, 480, 16, SDL_HWSURFACE); if(!bpp){ printf("Mode not available.\n"); exit(-1); } printf("SDL Recommends 640x480@%dbpp.\n", bpp); screen=SDL_SetVideoMode(640, 480, bpp, SDL_HWSURFACE); . .</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1228" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlsetvideomode.html" ><TT CLASS="FUNCTION" >SDL_SetVideoMode</TT ></A >, <A HREF="sdlgetvideoinfo.html" ><TT CLASS="FUNCTION" >SDL_GetVideoInfo</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="sdllistmodes.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="sdlsetvideomode.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_ListModes</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_SetVideoMode</TD ></TR ></TABLE ></DIV ></BODY ></HTML >