Mercurial > sdl-ios-xcode
view docs/html/sdlcreatergbsurfacefrom.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_CreateRGBSurfaceFrom</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_CreateRGBSurface" HREF="sdlcreatergbsurface.html"><LINK REL="NEXT" TITLE="SDL_FreeSurface" HREF="sdlfreesurface.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="sdlcreatergbsurface.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlfreesurface.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCREATERGBSURFACEFROM" ></A >SDL_CreateRGBSurfaceFrom</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1856" ></A ><H2 >Name</H2 >SDL_CreateRGBSurfaceFrom -- Create an SDL_Surface from pixel data</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1859" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN1860" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_Surface *<B CLASS="FSFUNC" >SDL_CreateRGBSurfaceFrom</B ></CODE >(void *pixels, int width, int height, int depth, int pitch, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1866" ></A ><H2 >Description</H2 ><P >Creates an SDL_Surface from the provided pixel data.</P ><P >The data stored in <TT CLASS="PARAMETER" ><I >pixels</I ></TT > is assumed to be of the <TT CLASS="PARAMETER" ><I >depth</I ></TT > specified in the parameter list. The pixel data is not copied into the <SPAN CLASS="STRUCTNAME" >SDL_Surface</SPAN > structure so it should not be freed until the surface has been freed with a called to <A HREF="sdlfreesurface.html" >SDL_FreeSurface</A >. <TT CLASS="PARAMETER" ><I >pitch</I ></TT > is the length of each scanline in bytes. </P ><P >See <A HREF="sdlcreatergbsurface.html" ><TT CLASS="FUNCTION" >SDL_CreateRGBSurface</TT ></A > for a more detailed description of the other parameters.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1878" ></A ><H2 >Return Value</H2 ><P >Returns the created surface, or <SPAN CLASS="RETURNVALUE" >NULL</SPAN > upon error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1882" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcreatergbsurface.html" ><TT CLASS="FUNCTION" >SDL_CreateRGBSurface</TT ></A >, <A HREF="sdlfreesurface.html" ><TT CLASS="FUNCTION" >SDL_FreeSurface</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="sdlcreatergbsurface.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="sdlfreesurface.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_CreateRGBSurface</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_FreeSurface</TD ></TR ></TABLE ></DIV ></BODY ></HTML >