glxcmds.c

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

fbconfigs_compatible( const __GLcontextModes * const a,
		      const __GLcontextModes * const b )
{
    MATCH_DONT_CARE( doubleBufferMode );
    MATCH_DONT_CARE( visualType );
    MATCH_DONT_CARE( visualRating );
    MATCH_DONT_CARE( xRenderable );
    MATCH_DONT_CARE( fbconfigID );
    MATCH_DONT_CARE( swapMethod );

    MATCH_MINIMUM( rgbBits );
    MATCH_MINIMUM( numAuxBuffers );
    MATCH_MINIMUM( redBits );
    MATCH_MINIMUM( greenBits );
    MATCH_MINIMUM( blueBits );
    MATCH_MINIMUM( alphaBits );
    MATCH_MINIMUM( depthBits );
    MATCH_MINIMUM( stencilBits );
    MATCH_MINIMUM( accumRedBits );
    MATCH_MINIMUM( accumGreenBits );
    MATCH_MINIMUM( accumBlueBits );
    MATCH_MINIMUM( accumAlphaBits );
    MATCH_MINIMUM( sampleBuffers );
    MATCH_MINIMUM( maxPbufferWidth );
    MATCH_MINIMUM( maxPbufferHeight );
    MATCH_MINIMUM( maxPbufferPixels );
    MATCH_MINIMUM( samples );

    MATCH_DONT_CARE( stereoMode );
    MATCH_EXACT( level );

    if ( ((a->drawableType & b->drawableType) == 0)
	 || ((a->renderType & b->renderType) == 0) ) {
	return False;
    }


    /* There is a bug in a few of the XFree86 DDX drivers.  They contain
     * visuals with a "transparent type" of 0 when they really mean GLX_NONE.
     * Technically speaking, it is a bug in the DDX driver, but there is
     * enough of an installed base to work around the problem here.  In any
     * case, 0 is not a valid value of the transparent type, so we'll treat 0 
     * from the app as GLX_DONT_CARE. We'll consider GLX_NONE from the app and
     * 0 from the server to be a match to maintain backward compatibility with
     * the (broken) drivers.
     */

    if ( a->transparentPixel != GLX_DONT_CARE
         && a->transparentPixel != 0 ) {
        if ( a->transparentPixel == GLX_NONE ) {
            if ( b->transparentPixel != GLX_NONE && b->transparentPixel != 0 )
                return False;
        } else {
            MATCH_EXACT( transparentPixel );
        }

	switch ( a->transparentPixel ) {
	  case GLX_TRANSPARENT_RGB:
	    MATCH_DONT_CARE( transparentRed );
	    MATCH_DONT_CARE( transparentGreen );
	    MATCH_DONT_CARE( transparentBlue );
	    MATCH_DONT_CARE( transparentAlpha );
	    break;

	  case GLX_TRANSPARENT_INDEX:
	    MATCH_DONT_CARE( transparentIndex );
	    break;

	  default:
	    break;
	}
    }

    return True;
}


/* There's some trickly language in the GLX spec about how this is supposed
 * to work.  Basically, if a given component size is either not specified
 * or the requested size is zero, it is supposed to act like PERFER_SMALLER.
 * Well, that's really hard to do with the code as-is.  This behavior is
 * closer to correct, but still not technically right.
 */
#define PREFER_LARGER_OR_ZERO(comp) \
    do { \
	if ( ((*a)-> comp) != ((*b)-> comp) ) { \
	    if ( ((*a)-> comp) == 0 ) { \
		return -1; \
	    } \
	    else if ( ((*b)-> comp) == 0 ) { \
		return 1; \
	    } \
	    else { \
		return ((*b)-> comp) - ((*a)-> comp) ; \
	    } \
	} \
    } while( 0 )

#define PREFER_LARGER(comp) \
    do { \
	if ( ((*a)-> comp) != ((*b)-> comp) ) { \
	    return ((*b)-> comp) - ((*a)-> comp) ; \
	} \
    } while( 0 )

#define PREFER_SMALLER(comp) \
    do { \
	if ( ((*a)-> comp) != ((*b)-> comp) ) { \
	    return ((*a)-> comp) - ((*b)-> comp) ; \
	} \
    } while( 0 )

/**
 * Compare two GLXFBConfigs.  This function is intended to be used as the
 * compare function passed in to qsort.
 * 
 * \returns If \c a is a "better" config, according to the specification of
 *          SGIX_fbconfig, a number less than zero is returned.  If \c b is
 *          better, then a number greater than zero is return.  If both are
 *          equal, zero is returned.
 * \sa qsort, glXChooseVisual, glXChooseFBConfig, glXChooseFBConfigSGIX
 */
static int
fbconfig_compare( const __GLcontextModes * const * const a,
		  const __GLcontextModes * const * const b )
{
    /* The order of these comparisons must NOT change.  It is defined by
     * the GLX 1.3 spec and ARB_multisample.
     */

    PREFER_SMALLER( visualSelectGroup );

    /* The sort order for the visualRating is GLX_NONE, GLX_SLOW, and
     * GLX_NON_CONFORMANT_CONFIG.  It just so happens that this is the
     * numerical sort order of the enums (0x8000, 0x8001, and 0x800D).
     */
    PREFER_SMALLER( visualRating );

    /* This isn't quite right.  It is supposed to compare the sum of the
     * components the user specifically set minimums for.
     */
    PREFER_LARGER_OR_ZERO( redBits );
    PREFER_LARGER_OR_ZERO( greenBits );
    PREFER_LARGER_OR_ZERO( blueBits );
    PREFER_LARGER_OR_ZERO( alphaBits );

    PREFER_SMALLER( rgbBits );

    if ( ((*a)->doubleBufferMode != (*b)->doubleBufferMode) ) {
	/* Prefer single-buffer.
	 */
	return ( !(*a)->doubleBufferMode ) ? -1 : 1;
    }

    PREFER_SMALLER( numAuxBuffers );

    PREFER_LARGER_OR_ZERO( depthBits );
    PREFER_SMALLER( stencilBits );

    /* This isn't quite right.  It is supposed to compare the sum of the
     * components the user specifically set minimums for.
     */
    PREFER_LARGER_OR_ZERO( accumRedBits );
    PREFER_LARGER_OR_ZERO( accumGreenBits );
    PREFER_LARGER_OR_ZERO( accumBlueBits );
    PREFER_LARGER_OR_ZERO( accumAlphaBits );

    PREFER_SMALLER( visualType );

    /* None of the multisample specs say where this comparison should happen,
     * so I put it near the end.
     */
    PREFER_SMALLER( sampleBuffers );
    PREFER_SMALLER( samples );

    /* None of the pbuffer or fbconfig specs say that this comparison needs
     * to happen at all, but it seems like it should.
     */
    PREFER_LARGER( maxPbufferWidth );
    PREFER_LARGER( maxPbufferHeight );
    PREFER_LARGER( maxPbufferPixels );

    return 0;
}


/**
 * Selects and sorts a subset of the supplied configs based on the attributes.
 * This function forms to basis of \c glXChooseVisual, \c glXChooseFBConfig,
 * and \c glXChooseFBConfigSGIX.
 * 
 * \param configs   Array of pointers to possible configs.  The elements of
 *                  this array that do not meet the criteria will be set to
 *                  NULL.  The remaining elements will be sorted according to
 *                  the various visual / FBConfig selection rules.
 * \param num_configs  Number of elements in the \c configs array.
 * \param attribList   Attributes used select from \c configs.  This array is
 *                     terminated by a \c None tag.  The array can either take
 *                     the form expected by \c glXChooseVisual (where boolean
 *                     tags do not have a value) or by \c glXChooseFBConfig
 *                     (where every tag has a value).
 * \param fbconfig_style_tags  Selects whether \c attribList is in
 *                             \c glXChooseVisual style or
 *                             \c glXChooseFBConfig style.
 * \returns The number of valid elements left in \c configs.
 * 
 * \sa glXChooseVisual, glXChooseFBConfig, glXChooseFBConfigSGIX
 */
static int
choose_visual( __GLcontextModes ** configs, int num_configs,
	       const int *attribList, GLboolean fbconfig_style_tags )
{
    __GLcontextModes    test_config;
    int   base;
    int   i;

    /* This is a fairly direct implementation of the selection method
     * described by GLX_SGIX_fbconfig.  Start by culling out all the
     * configs that are not compatible with the selected parameter
     * list.
     */

    init_fbconfig_for_chooser( & test_config, fbconfig_style_tags );
    __glXInitializeVisualConfigFromTags( & test_config, 512,
					 (const INT32 *) attribList,
					 GL_TRUE, fbconfig_style_tags );

    base = 0;
    for ( i = 0 ; i < num_configs ; i++ ) {
	if ( fbconfigs_compatible( & test_config, configs[i] ) ) {
	    configs[ base ] = configs[ i ];
	    base++;
	}
    }

    if ( base == 0 ) {
	return 0;
    }
 
    if ( base < num_configs ) {
	(void) memset( & configs[ base ], 0, 
		       sizeof( void * ) * (num_configs - base) );
    }

    /* After the incompatible configs are removed, the resulting
     * list is sorted according to the rules set out in the various
     * specifications.
     */
    
    qsort( configs, base, sizeof( __GLcontextModes * ),
	   (int (*)(const void*, const void*)) fbconfig_compare );
    return base;
}




/*
** Return the visual that best matches the template.  Return None if no
** visual matches the template.
*/
PUBLIC XVisualInfo *glXChooseVisual(Display *dpy, int screen, int *attribList)
{
    XVisualInfo *visualList = NULL;
    __GLXdisplayPrivate *priv;
    __GLXscreenConfigs *psc;
    __GLcontextModes  test_config;
    __GLcontextModes *modes;
    const __GLcontextModes *best_config = NULL;

    /*
    ** Get a list of all visuals, return if list is empty
    */
    if ( GetGLXPrivScreenConfig( dpy, screen, & priv, & psc ) != Success ) {
	return None;
    }
   

    /*
    ** Build a template from the defaults and the attribute list
    ** Free visual list and return if an unexpected token is encountered
    */
    init_fbconfig_for_chooser( & test_config, GL_FALSE );
    __glXInitializeVisualConfigFromTags( & test_config, 512, 
					 (const INT32 *) attribList,
					 GL_TRUE, GL_FALSE );

    /*
    ** Eliminate visuals that don't meet minimum requirements
    ** Compute a score for those that do
    ** Remember which visual, if any, got the highest score
    */
    for ( modes = psc->visuals ; modes != NULL ; modes = modes->next ) {
	if ( fbconfigs_compatible( & test_config, modes )
	     && ((best_config == NULL)
		 || (fbconfig_compare( (const __GLcontextModes * const * const)&modes, &best_config ) < 0)) ) {
	    best_config = modes;
	}
    }

    /*
    ** If no visual is acceptable, return None
    ** Otherwise, create an XVisualInfo list with just the selected X visual
    ** and return this.
    */
    if (best_config != NULL) {
	XVisualInfo visualTemplate;
	int  i;

	visualTemplate.screen = screen;
	visualTemplate.visualid = best_config->visualID;
	visualList = XGetVisualInfo( dpy, VisualScreenMask|VisualIDMask,
				     &visualTemplate, &i );
    }

    return visualList;
}


PUBLIC const char *glXQueryExtensionsString( Display *dpy, int screen )
{
    __GLXscreenConfigs *psc;
    __GLXdisplayPrivate *priv;

    if ( GetGLXPrivScreenConfig( dpy, screen, & priv, & psc ) != Success ) {
	return NULL;
    }

    if (!psc->effectiveGLXexts) {
        if (!psc->serverGLXexts) {
	    psc->serverGLXexts = __glXGetStringFromServer(dpy, priv->majorOpcode,
					  	   X_GLXQueryServerString,
					  	   screen, GLX_EXTENSIONS);
	}

	__glXCalculateUsableExtensions(psc,
#ifdef GLX_DIRECT_RENDERING
				       (psc->driScreen != NULL),
#else
				       GL_FALSE,
#endif
				       priv->minorVersion);
    }

    return psc->effectiveGLXexts;
}

PUBLIC const char *glXGetClientString( Display *dpy, int name )
{
    switch(name) {
	case GLX_VENDOR:
	    return (__glXGLXClientVendorName);
	case GLX_VERSION:
	    return (__glXGLXClientVersion);
	case GLX_EXTENSIONS:
	    return (__glXGetClientExtensions());
	default:
	    return NULL;
    }
}

PUBLIC const char *glXQueryServerString( Display *dpy, int screen, int name )
{
    __GLXscreenConfigs *psc;
    __GLXdisplayPrivate *priv;
    const char ** str;


    if ( GetGLXPrivScreenConfig( dpy, screen, & priv, & psc ) != Success ) {
	return NULL;
    }

    switch(name) {
	case GLX_VENDOR:
	    str = & priv->serverGLXvendor;
	    break;
	case GLX_VERSION:
	    str = & priv->serverGLXversion;
	    break;
	case GLX_EXTENSIONS:
	    str = & psc->serverGLXexts;
	    break;
	default:
	    return NULL;
    }

    if ( *str == NULL ) {
	*str = __glXGetStringFromServer(dpy, priv->majorOpcode,
					X_GLXQueryServerString, screen, name);
    }
    
    return *str;
}

void __glXClientInfo (  Display *dpy, int opcode  )
{
    xGLXClientInfoReq *req;
    int size;
    char * ext_str = __glXGetClientGLExtensionString();

    /* Send the glXClientInfo request */
    LockDisplay(dpy);
    GetReq(GLXClientInfo,req);
    req->reqType = opcode;
    req->glxCode = X_GLXClientInfo;
    req->major = GLX_MAJOR_VERSION;
    req->minor = GLX_MINOR_VERSION;

    size = strlen( ext_str ) + 1;
    req->length += (size + 3) >> 2;
    req->numbytes = size;
    Data(dpy, ext_str, size);

    UnlockDisplay(dpy);
    SyncHandle();
    
    Xfree( ext_str );
}


/*
** EXT_import_context
*/

PUBLIC Display *glXGetCurrentDisplay(void)
{
    GLXContext gc = __glXGetCurrentContext();
    if (NULL == gc) return NULL;
    return gc->currentDpy;
}

PUBLIC GLX_ALIAS(Display *, glXGetCurrentDisplayEXT, (void), (),
	  glXGetCurrentDisplay)

/**
 * Used internally by libGL to send \c xGLXQueryContextinfoExtReq requests
 * to the X-server.
 * 
 * \param dpy  Display where \c ctx was created.
 * \param ctx  Context to query.
 * \returns  \c Success on success.  \c GLX_BAD_CONTEXT if \c ctx is invalid,
 *           or zero if the request failed due to internal problems (i.e.,
 *           unable to allocate temporary memory, etc.)
 * 
 * \note
 * This function dynamically determines whether to use the EXT_import_context
 * version of the protocol or the GLX 1.3 version of the protocol.
 */
static int __glXQueryContextInfo(Display *dpy, GLXContext ctx)
{
    __GLXdisplayPrivate *priv = __glXInitialize(dpy);
    xGLXQueryContextReply reply;
    CARD8 opcode;
    GLuint numValues;
    int retval;

    if (ctx == NULL) {
	return GLX_BAD_CONTEXT;
    }
    opcode = __glXSetupForCommand(dpy);
    if (!opcode) {
	return 0;
    }

    /* Send the glXQueryContextInfoEXT request */
    LockDisplay(dpy);

    if ( (priv->majorVersion > 1) || (priv->minorVersion >= 3) ) {
	xGLXQueryContextReq *req;

	GetReq(GLXQueryContext, req);

	req->reqType = opcode;
	req->glxCode = X_GLXQueryContext;
	req->context = (unsigned int)(ctx->xid);
    }
    else {
	xGLXVendorPrivateReq *vpreq;
	xGLXQueryContextInfoEXTReq *req;

	GetReqExtra( GLXVendorPrivate,
		     sz_xGLXQueryContextInfoEXTReq - sz_xGLXVendorPrivateReq,
		     vpreq );
	req = (xGLXQueryContextInfoEXTReq *)vpreq;
	req->reqType = opcode;
	req->glxCode = X_GLXVendorPrivateWithReply;
	req->vendorCode = X_GLXvop_QueryContextInfoEXT;
	req->context = (unsigned int)(ctx->xid);
    }

    _XReply(dpy, (xReply*) &reply, 0, False);

    numValues = reply.n;