SDL_GL_GetProcAddress

Name

SDL_GL_GetProcAddress -- Get the address of a GL function

Synopsis

#include "SDL.h"

void *SDL_GL_GetProcAddress(const char* proc);

Description

Returns the address of the GL function proc, or NULL if the function is not found. If the GL library is loaded at runtime, with SDL_GL_LoadLibrary, then all GL functions must be retrieved this way. Usually this is used to retrieve function pointers to OpenGL extensions. Note that this function needs an OpenGL context to function properly, so it should be called after SDL_SetVideoMode has been called (with the SDL_OPENGL flag).

OpenGL function pointers must be declared APIENTRY as in the example code. This will ensure the proper calling convention is followed on platforms where this matters (Win32) thereby avoiding stack corruption. In a Win32 build environment, APIENTRY should be defined as __stdcall.

Return Value

Returns the address of the GL function proc, or NULL if the function is not found.

Example

typedef void (APIENTRY * 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{
  .
  .
}

See Also

SDL_GL_LoadLibrary

SDL_GL_GetProcAddress (last edited 2008-04-17 08:18:34 by localhost)