Mercurial > sdl-ios-xcode

view docs/html/sdlglsetattribute.html @ 1240:3b8a43c428bb

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
From Bug #36: There are a couple of issues with the selection of Altivec alpha-blitting routines in CalculateAlphaBlit() in src/video/SDL_Blit_A.c. 1) There's no check for the presence of Altivec when checking if the Blit32to565PixelAlphaAltivec() routine can be selected. 2) Altivec cannot be used in video memory, and there's no check if the destination surface is a hardware surface. (Alpha-blitting to a hardware surface with GPU support is a bad idea, but somebody's bound to do it anyway.) Patch to fix these attached.
author Ryan C. Gordon <icculus@icculus.org>
date Sun, 08 Jan 2006 21:18:15 +0000
parents 355632dca928
children
line wrap: on
line source

<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&nbsp;--&nbsp;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
>