Mercurial > sdl-ios-xcode
view docs/html/sdlglsetattribute.html @ 2042:3908e1f808e1
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 15:56:36 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_GL_SetAttribute</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_GL_GetAttribute" HREF="sdlglgetattribute.html"><LINK REL="NEXT" TITLE="SDL_GL_SwapBuffers" HREF="sdlglswapbuffers.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="sdlglgetattribute.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlglswapbuffers.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLGLSETATTRIBUTE" ></A >SDL_GL_SetAttribute</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN2742" ></A ><H2 >Name</H2 >SDL_GL_SetAttribute -- Set a special SDL/OpenGL attribute</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN2745" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN2746" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_GL_SetAttribute</B ></CODE >(SDL_GLattr attr, int value);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2752" ></A ><H2 >Description</H2 ><P >Sets the OpenGL <A HREF="sdlglattr.html" >attribute</A > <TT CLASS="PARAMETER" ><I >attr</I ></TT > to <TT CLASS="PARAMETER" ><I >value</I ></TT >. The attributes you set don't take effect until after a call to <A HREF="sdlsetvideomode.html" ><TT CLASS="FUNCTION" >SDL_SetVideoMode</TT ></A >. You should use <A HREF="sdlglgetattribute.html" ><TT CLASS="FUNCTION" >SDL_GL_GetAttribute</TT ></A > to check the values after a <TT CLASS="FUNCTION" >SDL_SetVideoMode</TT > call.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2763" ></A ><H2 >Return Value</H2 ><P >Returns <SPAN CLASS="RETURNVALUE" >0</SPAN > on success, or <SPAN CLASS="RETURNVALUE" >-1</SPAN > on error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2768" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 ); SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 ); SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 ); SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 ); SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 ); if ( (screen=SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL )) == NULL ) { fprintf(stderr, "Couldn't set GL mode: %s\n", SDL_GetError()); SDL_Quit(); return; }</PRE ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B >The <TT CLASS="LITERAL" >SDL_DOUBLEBUF</TT > flag is not required to enable double buffering when setting an OpenGL video mode. Double buffering is enabled or disabled using the SDL_GL_DOUBLEBUFFER attribute.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2774" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlglgetattribute.html" ><TT CLASS="FUNCTION" >SDL_GL_GetAttribute</TT ></A >, <A HREF="sdlglattr.html" >GL Attributes</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="sdlglgetattribute.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="sdlglswapbuffers.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_GL_GetAttribute</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_GL_SwapBuffers</TD ></TR ></TABLE ></DIV ></BODY ></HTML >