extensions/SGIX/SGIX_list_priority.txt

XXX - Not complete yet!!!

Name

    SGIX_list_priority

Name Strings

    GL_SGIX_list_priority

Version

    $Date: 1996/05/30 08:00:32 $ $Revision: 1.3 $

Number

    80

Dependencies

    None

Overview

    This extension provides a mechanism for specifying the relative
    importance of display lists.  This information can be used by
    an OpenGL implementation to guide the placement of display
    list data in a storage hierarchy.

Issues

    *	Should we also add some hints to guide compilation strategies
    	For example a hint could give us the equivalent of the iris gl
	compactify command.  Generally hints could control compilation
	speed versus memory consumption, degree of optimization, etc.

	yes, in another spec
    
    *   Should we go ahead and add a ListParameter command rather than a
	PrioritorizeList command just in case some other list attribute
	needs to be added.  Do we go ahead and finish the job with
	f,i,iv functions?

	yes
    
    *	Is 1.0 a reasonable default?

    *	Should it be an SGI rather than SGIX extension?
    
New Procedures and Functions

    ListParameterfSGIX(uint list,
		        enum pname,
		        float params;

    ListParameterfvSGIX(uint list,
		        enum pname,
		        float *params);

    ListParameteriSGIX(uint list,
		        enum pname,
		        int param);

    ListParameterivSGIX(uint list,
		        enum pname,
		        int *params);

    GetListParameterfvSGIX(uint list,
		           enum pname,
		           float *params);

    GetListParameterivSGIX(uint list,
		           enum pname,
		           int *params);

New Tokens

    Accepted by the <pname> parameters of ListParameterfSGIX,
    ListParameterfvSGIX, ListParameteriSGIX, ListParameterivSGIX,
    GetListParameterfvSGIX, and GetListParameterivSGIX:

	LIST_PRIORITY_SGIX

Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation)

    None

Additions to Chapter 3 of the 1.0 Specification (Rasterization)

    None

Additions to Chapter 4 of the 1.0 Specification (Per-Fragment Operations
and the Frame Buffer)

    None

Additions to Chapter 5 of the 1.0 Specification (Special Functions)

    Applications guide the OpenGL implementation in determining which
    display lists should be favoured for fast execution by specifying
    a priority for each display list.  Calling ListParameterfSGIX,
    ListParameterfvSGIX, ListParameteriSGIX, or ListParameterivSGIX
    with <list> set to the display list, <pname> set to LIST_PRIORITY_SGIX,
    sets the priority to the value in <params>.
    The priority value is clamped to the range [0.0, 1.0] before it is
    assigned.  Zero indicates the lowest priority, and hence the least
    likelihood of optimal execution.  One indicates the highest priority,
    and hence the greatest likelihood of optimal execution.
    (Attempts attempts to prioritize nonlists are silently ignored. Attempts
    to prioritize list 0 generates an INVALID_VALUE error.)

    The priority of a list can be queried by calling GetListParameterfvSGIX or
    GetListParameterivSGIX with <list> set to the list and <pname> set to
    LIST_PRIORITY_SGIX. If <list> is not defined than the value returned
    is undefined.

    ListParameterfSGIX, ListParameterfvSGIX, ListParameteriSGIX, and
    ListParameterivSGIX are not included in display lists.

Additions to Chapter 6 of the 1.0 Specification (State and State Requests)

    None

Additions to the GLX Specification

    TBD

Errors

    INVALID_VALUE is generated if ListParameterfSGIX, ListParameterfvSGIX,
    ListParameteriSGIX, ListParameterivSGIX, GetListParameterfvSGIX, or
    GetListParameterivSGIX parameter <list> is 0.

    INVALID_ENUM is generated if ListParameterfSGIX, ListParameterfvSGIX,
    ListParameteriSGIX, ListParameterivSGIX, GetListParameterfvSGIX, or
    GetListParameterivSGIX parameter <pname> is not LIST_PRIORITY_SGIX.

    INVALID_OPERATION is generated if ListParameterfSGIX, ListParameterfvSGIX,
    ListParameteriSGIX, ListParameterivSGIX, GetListParameterfvSGIX, or
    GetListParameterivSGIX is called between execution of Begin and the
    corresponding execution of End.

New State

								          Initial
    Get Value				Get Command	        Type	  Value	    Attrib
    ---------				-----------	        ----	  -------   ------
    LIST_PRIORITY_SGIX                  GetListParameterfvSGIX  n x Z+    1           -


New Implementation Dependent State

    None