view docs/html/sdlglgetprocaddress.html @ 3957:b1d5b56aa549 SDL-1.2

Date: Mon, 4 Jun 2007 06:17:59 +0000 (UTC) From: George Gensure <werkt0@gmail.com> Subject: [SDL] error removal patch for SDL_x11dyn.c I found that calling SDL_GetError when an error hasn't necessarily occurred is still reporting problems from loadso regarding dynamic functions in X11. I've added the following to my local copy to avoid revealing the 'many library lookup' approach adopted by x11dyn.c:
author Ryan C. Gordon <icculus@icculus.org>
date Wed, 13 Jun 2007 07:54:10 +0000
parents 355632dca928
children
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>SDL_GL_GetProcAddress</TITLE
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>SDL_GL_GetProcAddress</H1
><DIV
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><A
NAME="AEN2678"
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><H2
>Name</H2
>SDL_GL_GetProcAddress&nbsp;--&nbsp;Get the address of a GL function</DIV
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>Synopsis</H2
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><P
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>void *<B
CLASS="FSFUNC"
>SDL_GL_GetProcAddress</B
></CODE
>(const char* proc);</CODE
></P
><P
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><DIV
CLASS="REFSECT1"
><A
NAME="AEN2688"
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><H2
>Description</H2
><P
>Returns the address of the GL function <TT
CLASS="PARAMETER"
><I
>proc</I
></TT
>, or <SPAN
CLASS="RETURNVALUE"
>NULL</SPAN
> if the function is not found. If the GL library is loaded at runtime, with <A
HREF="sdlglloadlibrary.html"
><TT
CLASS="FUNCTION"
>SDL_GL_LoadLibrary</TT
></A
>, then <SPAN
CLASS="emphasis"
><I
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>all</I
></SPAN
> GL functions must be retrieved this way. Usually this is used to retrieve function pointers to OpenGL extensions.</P
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><H2
>Example</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef void (*GL_ActiveTextureARB_Func)(unsigned int);
GL_ActiveTextureARB_Func glActiveTextureARB_ptr = 0;
int has_multitexture=1;
.
.
.
/* Get function pointer */
glActiveTextureARB_ptr=(GL_ActiveTextureARB_Func) SDL_GL_GetProcAddress("glActiveTextureARB");

/* Check for a valid function ptr */
if(!glActiveTextureARB_ptr){
  fprintf(stderr, "Multitexture Extensions not present.\n");
  has_multitexture=0;
}
.
.
.
.
if(has_multitexture){
  glActiveTextureARB_ptr(GL_TEXTURE0_ARB);
  .
  .
}
else{
  .
  .
}</PRE
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>SDL_GL_LoadLibrary</TT
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