[pkg-nvidia-devel] Bug#445363: nvidia-glx incompatible to xlibmesa-gl-dev

[bug-nvidia-glx at karimmi.de]

Package: nvidia-glx
Version: 1.0.7174-3
Tags: patch

When one has nvidia-glx installed and compiles programs which use libGL, 
compilation works but the resulting program often does not. Below an 
example program.

The reason seems to be that when both xlibmesa-gl-dev and nvidia-glx are 
installed, then the symlink /usr/lib/libGL.so is broken. Replacing this 
link by a link to the correct libGL.so.xxx fixes the bug. (I think the 
package nvidia-glx should care about this.)

I am using Sarge, but as far as I can tell, the bug is still there in 
Etch.




Example program follows (code copy-pasted out of sdl examples and out of 
extreme-tuxracer). Compile the program with

g++ -I../include -g test.cc -L../lib -lGLU -lGL  -lpthread -lSDL -o test

The program outputs 

  vendor: (null)
  renderer: (null)
  version: (null)
  extensions: (null)

when it does not work and correct information after bugfix.
-----


#include <SDL/SDL.h>
#include <GL/gl.h>
#include <GL/glu.h>
#include <cstdarg>
#include <cstdlib>
#include <cstdio>
#include <cstring>


static SDL_Surface *screen = NULL;

/* Extension func ptrs *must* be initialized to NULL */
PFNGLLOCKARRAYSEXTPROC glLockArraysEXT_p = NULL;
PFNGLUNLOCKARRAYSEXTPROC glUnlockArraysEXT_p = NULL;

typedef void (*(*get_gl_proc_fptr_t)(const GLubyte *))(); 

void init_opengl_extensions()
{
    get_gl_proc_fptr_t get_gl_proc;
    get_gl_proc = (get_gl_proc_fptr_t) SDL_GL_GetProcAddress;
    if ( get_gl_proc ) {
	glLockArraysEXT_p = (PFNGLLOCKARRAYSEXTPROC) 
	    (*get_gl_proc)( (GLubyte*) "glLockArraysEXT" );
	glUnlockArraysEXT_p = (PFNGLUNLOCKARRAYSEXTPROC) 
	    (*get_gl_proc)( (GLubyte*) "glUnlockArraysEXT" );
	if ( glLockArraysEXT_p != NULL && glUnlockArraysEXT_p != NULL ) 
{
	} else {
	    glLockArraysEXT_p = NULL;
	    glUnlockArraysEXT_p = NULL;
	}
    }
}

void print_gl_info()
{
    fprintf( stderr, "  vendor: %s\n", glGetString( GL_VENDOR ) );
    fprintf( stderr, "  renderer: %s\n", glGetString( GL_RENDERER ) );
    fprintf( stderr, "  version: %s\n", glGetString( GL_VERSION ) );
    fprintf( stderr, "  extensions: %s\n", glGetString( GL_EXTENSIONS ) 
);
}




void setup_sdl_video_mode()
{
    Uint32 video_flags = SDL_OPENGL; 
    int bpp = 0;
    int width, height;
    video_flags |= SDL_RESIZABLE;
    bpp = 0;
    width = 800;
    height = 600;
    if ((screen = SDL_SetVideoMode(width, height, bpp, video_flags)) ==  
NULL){
    	exit(1);
    }
    glViewport(0,0,width,height);
}


void winsys_init( int *argc, char **argv, char *window_title, 
		  char *icon_title ) {
    Uint32 sdl_flags = SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE;
    if ( SDL_Init( sdl_flags ) < 0 ) { exit(1); }
    SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
    setup_sdl_video_mode();
    SDL_WM_SetCaption( window_title, icon_title );
}






int main( int argc, char *argv[] )  {
    winsys_init( &argc, argv, "test", "test" );
    glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
    init_opengl_extensions();
    print_gl_info();
    return 0;
}