glxextensions.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

      }
   }
}

void
__glXEnableDirectExtension(__GLXscreenConfigs *psc, const char *name)
{
    __glXExtensionsCtr();
    __glXExtensionsCtrScreen(psc);

    set_glx_extension(known_glx_extensions,
		      name, strlen(name), GL_TRUE, psc->direct_support);
}

/**
 * Initialize global extension support tables.
 */

static void
__glXExtensionsCtr( void )
{
   unsigned   i;
   static GLboolean ext_list_first_time = GL_TRUE;


   if ( ext_list_first_time ) {
      ext_list_first_time = GL_FALSE;

      (void) memset( client_glx_support, 0, sizeof( client_glx_support ) );
      (void) memset( direct_glx_support, 0, sizeof( direct_glx_support ) );
      (void) memset( client_glx_only,    0, sizeof( client_glx_only ) );
      (void) memset( direct_glx_only,    0, sizeof( direct_glx_only ) );

      (void) memset( client_gl_support,  0, sizeof( client_gl_support ) );
      (void) memset( client_gl_only,     0, sizeof( client_gl_only ) );

      for ( i = 0 ; known_glx_extensions[i].name != NULL ; i++ ) {
	 const unsigned  bit = known_glx_extensions[i].bit;

	 if ( known_glx_extensions[i].client_support ) {
	    SET_BIT( client_glx_support, bit );
	 }

	 if ( known_glx_extensions[i].direct_support ) {
	    SET_BIT( direct_glx_support, bit );
	 }

	 if ( known_glx_extensions[i].client_only ) {
	    SET_BIT( client_glx_only, bit );
	 }

	 if ( known_glx_extensions[i].direct_only ) {
	    SET_BIT( direct_glx_only, bit );
	 }
      }

      for ( i = 0 ; known_gl_extensions[i].name != NULL ; i++ ) {
	 const unsigned  bit = known_gl_extensions[i].bit;

	 if ( known_gl_extensions[i].client_support ) {
	    SET_BIT( client_gl_support, bit );
	 }

	 if ( known_gl_extensions[i].client_only ) {
	    SET_BIT( client_gl_only, bit );
	 }
      }
      
#if 0
      fprintf( stderr, "[%s:%u] Maximum client library version: %u.%u\n",
	       __func__, __LINE__, gl_major, gl_minor );
#endif
   }
}


/**
 * Make sure that per-screen direct-support table is initialized.
 *
 * \param psc  Pointer to GLX per-screen record.
 */

static void
__glXExtensionsCtrScreen( __GLXscreenConfigs *psc )
{
    if (psc->ext_list_first_time) {
	psc->ext_list_first_time = GL_FALSE;
	(void) memcpy( psc->direct_support, direct_glx_support,
		       sizeof( direct_glx_support ) );
    }
}


/**
 * Check if a certain extension is enabled on a given screen.
 *
 * \param psc  Pointer to GLX per-screen record.
 * \param bit  Bit index in the direct-support table.
 * \returns If the extension bit is enabled for the screen, \c GL_TRUE is
 *          returned.  If the extension bit is not enabled or if \c psc is
 *          \c NULL, then \c GL_FALSE is returned.
 */
GLboolean
__glXExtensionBitIsEnabled( __GLXscreenConfigs *psc, unsigned bit )
{
   GLboolean enabled = GL_FALSE;

   if ( psc != NULL ) {
      __glXExtensionsCtr();
      __glXExtensionsCtrScreen( psc );
      enabled = EXT_ENABLED( bit, psc->direct_support );
   }

   return enabled;
}


/**
 * Check if a certain extension is enabled in a given context.
 *
 */
GLboolean
__glExtensionBitIsEnabled( const __GLXcontext * gc, unsigned bit )
{
   GLboolean enabled = GL_FALSE;

   if ( gc != NULL ) {
      enabled = EXT_ENABLED( bit, gc->gl_extension_bits );
   }

   return enabled;
}



/**
 * Convert a bit-field to a string of supported extensions.
 */
static char *
__glXGetStringFromTable( const struct extension_info * ext,
			 const unsigned char * supported )
{
   unsigned   i;
   unsigned   ext_str_len;
   char * ext_str;
   char * point;


   ext_str_len = 0;
   for ( i = 0 ; ext[i].name != NULL ; i++ ) {
      if ( EXT_ENABLED( ext[i].bit, supported ) ) {
	 ext_str_len += ext[i].name_len + 1;
      }
   }

   ext_str = Xmalloc( ext_str_len + 1 );
   if ( ext_str != NULL ) {
      point = ext_str;

      for ( i = 0 ; ext[i].name != NULL ; i++ ) {
	 if ( EXT_ENABLED( ext[i].bit, supported ) ) {
	    (void) memcpy( point, ext[i].name, ext[i].name_len );
	    point += ext[i].name_len;

	    *point = ' ';
	    point++;
	 }
      }

      *point = '\0';
   }

   return ext_str;
}


/**
 * Get the string of client library supported extensions.
 */
const char *
__glXGetClientExtensions( void )
{
   if ( __glXGLXClientExtensions == NULL ) {
      __glXExtensionsCtr();
      __glXGLXClientExtensions = __glXGetStringFromTable( known_glx_extensions,
							  client_glx_support );
   }

   return __glXGLXClientExtensions;
}


/**
 * Calculate the list of application usable extensions.  The resulting
 * string is stored in \c psc->effectiveGLXexts.
 * 
 * \param psc                        Pointer to GLX per-screen record.
 * \param display_is_direct_capable  True if the display is capable of
 *                                   direct rendering.
 * \param minor_version              GLX minor version from the server.
 */

void
__glXCalculateUsableExtensions( __GLXscreenConfigs *psc,
				GLboolean display_is_direct_capable,
				int minor_version )
{
   unsigned char server_support[8];
   unsigned char usable[8];
   unsigned      i;

   __glXExtensionsCtr();
   __glXExtensionsCtrScreen( psc );

   (void) memset( server_support, 0, sizeof( server_support ) );
   __glXProcessServerString( known_glx_extensions,
			     psc->serverGLXexts, server_support );


   /* This is a hack.  Some servers support GLX 1.3 but don't export
    * all of the extensions implied by GLX 1.3.  If the server claims
    * support for GLX 1.3, enable support for the extensions that can be
    * "emulated" as well.
    */

   if ( minor_version >= 3 ) {
      SET_BIT( server_support, EXT_visual_info_bit );
      SET_BIT( server_support, EXT_visual_rating_bit );
      SET_BIT( server_support, SGI_make_current_read_bit );
      SET_BIT( server_support, SGIX_fbconfig_bit );
      SET_BIT( server_support, SGIX_pbuffer_bit );
       
      /* This one is a little iffy.  GLX 1.3 doesn't incorporate all of this
       * extension.  However, the only part that is not strictly client-side
       * is shared.  That's the glXQueryContext / glXQueryContextInfoEXT
       * function.
       */

      SET_BIT( server_support, EXT_import_context_bit );
   }


   /* An extension is supported if the client-side (i.e., libGL) supports
    * it and the "server" supports it.  In this case that means that either
    * the true server supports it or it is only for direct-rendering and
    * the direct rendering driver supports it.
    * 
    * If the display is not capable of direct rendering, then the extension
    * is enabled if and only if the client-side library and the server
    * support it.
    */

   if ( display_is_direct_capable ) {
      for ( i = 0 ; i < 8 ; i++ ) {
	 usable[i] = (client_glx_support[i] & client_glx_only[i])
	     | (client_glx_support[i] & psc->direct_support[i] & server_support[i])
	     | (client_glx_support[i] & psc->direct_support[i] & direct_glx_only[i]);
      }
   }
   else {
      for ( i = 0 ; i < 8 ; i++ ) {
	 usable[i] = (client_glx_support[i] & client_glx_only[i])
	     | (client_glx_support[i] & server_support[i]);
      }
   }

   psc->effectiveGLXexts = __glXGetStringFromTable( known_glx_extensions,
						    usable );
}


/**
 * Calculate the list of application usable extensions.  The resulting
 * string is stored in \c gc->extensions.
 * 
 * \param gc             Pointer to GLX context.
 * \param server_string  Extension string from the server.
 * \param major_version  GL major version from the server.
 * \param minor_version  GL minor version from the server.
 */

void
__glXCalculateUsableGLExtensions( __GLXcontext * gc,
				  const char * server_string,
				  int major_version, int minor_version )
{
   unsigned char server_support[ __GL_EXT_BYTES ];
   unsigned char usable[ __GL_EXT_BYTES ];
   unsigned      i;


   __glXExtensionsCtr();

   (void) memset( server_support, 0, sizeof( server_support ) );
   __glXProcessServerString( known_gl_extensions, server_string,
			     server_support );


   /* Handle lazy servers that don't export all the extensions strings that
    * are part of the GL core version that they support.
    */

   for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
      if ( (known_gl_extensions[i].version_major != 0)
	   && ((major_version > known_gl_extensions[i].version_major)
	       || ((major_version == known_gl_extensions[i].version_major)
		   && (minor_version >= known_gl_extensions[i].version_minor))) ) {
	 SET_BIT( server_support, known_gl_extensions[i].bit );
      }
   }


   /* An extension is supported if the client-side (i.e., libGL) supports
    * it and the server supports it or the client-side library supports it
    * and it only needs client-side support.
    */

   for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
      usable[i] = (client_gl_support[i] & client_gl_only[i])
	| (client_gl_support[i] & server_support[i]);
   }

   gc->extensions = (unsigned char *) 
     __glXGetStringFromTable( known_gl_extensions, usable );
   (void) memcpy( gc->gl_extension_bits, usable, sizeof( usable ) );
}


/**
 * Calculates the maximum core GL version that can be supported for indirect
 * rendering.
 */
void
__glXGetGLVersion( int * major_version, int * minor_version )
{		   
    __glXExtensionsCtr();
    *major_version = gl_major;
    *minor_version = gl_minor;
}


/**
 * Get a string representing the set of extensions supported by the client
 * library.  This is currently only used to send the list of extensions
 * supported by the client to the server.
 */
char *
__glXGetClientGLExtensionString( void )
{
    __glXExtensionsCtr();
    return __glXGetStringFromTable( known_gl_extensions, client_gl_support );
}