Daniel F Gibbons

US Patent:

52553590, Oct 19, 1993

Filed:

Oct 23, 1989

Appl. No.:

7/425781

Inventors:

Timothy J. Ebbers - Shokan NY
Daniel G. Gibbons - Ulster Park NY
David W. Li - Kingston NY
Bob C. Liang - West Hurley NY
David C. Tannenbaum - Kingston NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 3153

US Classification:

395161

Abstract:

A graphics display system picking function tracks machine states of pickable primitive operators through the use of a pick stack and machine state memory. The pick stack operates as a stack when accessed by pipeline processors. Pipeline processors can add an element to the stack or remove elements from the stack as structures are processed. Selection or picking of an object causes a graphics control processor to randomly access the pick stack to determine the attributes of a picked primitive. The machine state memory is implemented as a video RAM allowing rapid copying of rows containing machine states for various structure levels in the hierarchy. A first area of the machine state memory stores the states relating to the structures in the hierarchy as they are executed. A second area retains an abbreviated state description for each pickable primitive while a final area contains abbreviated machine state information for picked objects to be echoed by the system. The pick stack and machine state memories operate together to provide rapid pick identification, picked primitive machine state identification, and picked primitive echoing.

US Patent:

52895769, Feb 22, 1994

Filed:

Mar 12, 1992

Appl. No.:

7/849920

Inventors:

Daniel G. Gibbons - Ulster Park NY
James A. Harstad - Dover MA
David C. Tannenbaum - Hurley NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1520

US Classification:

395162

Abstract:

A hardware filter for controlling the detectability, highlighting and invisibility of graphics primitives. Each of the three display attributes (detectability, highlighting, and invisibility) being controlled has associated with it both an inclusion counter and an exclusion counter, for a total of six counters. Associated with each class name is a flag, indicating whether the class name is a member of the currently active set, as well as a 6-bit string indicating the effect of the class on each of the six filters. On traversal of the structure hierarchy, upon encountering an order for the addition of a class name to the set, and if the flag corresponding to the class name has not already been set, the flag is set and the corresponding filter counters are incremented in parallel by gating an incrementing signal with the 6-bit string. Similarly, upon encountering an order for the removal of a class name to the set, and the flag corresponding to the class name has not been reset, the flag is reset and the corresponding filter counters are decremented by gating a decrementing signal with the 6-bit string. Subsequently encountered primitives are considered as detectable, highlighted or invisible if the corresponding inclusion filter counter is greater than zero, indicating that the primitive belongs to at least one included class, and the corresponding exclusion filter counter is zero, indicating that the primitive does not belong to any excluded class.

US Patent:

51485214, Sep 15, 1992

Filed:

Oct 23, 1989

Appl. No.:

7/425776

Inventors:

Timothy J. Ebbers - Shokan NY
Daniel G. Gibbons - Ulster Park NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1520

US Classification:

395155

Abstract:

A pick queue and pick detection method that allows non-hierarchical graphic data models and applications to be used with pipelined processing systems. Pretransformed formatting logic is placed prior to pipeline processors to store necessary picking information in a pick queue. A pick tag addressing the pick queue is passed with each graphics order through the pipeline and stored in the pick detect logic. The pick detect logic interrupts the graphics control processor that then accesses the tag register associated with the graphics order and the coordinate counter to address the stored pick information of the order triggering the pick. The graphics processor uses the tag address and coordinate counter to indirectly address the pick queue and retrieve the information that needs to be passed back to the application program. The structure eliminates the requirement to pass all information through the pipeline processors.

US Patent:

52089096, May 4, 1993

Filed:

Oct 23, 1989

Appl. No.:

7/425777

Inventors:

James Corona - Kingston NY
Daniel G. Gibbons - Ulster Park NY
Terence W. Lindgren - Littleton MA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1562
G06F 314

US Classification:

395155

Abstract:

A method and apparatus for detecting operator selection of a graphics object prior to rasterization and pixel generation for that object. The method divides the screen into regions and analyzes successive end points and vectors based upon their region to determine trivial picks and trivial no picks. Non-trivial conditions are analyzed by determining the position of the line segment being processed relative to two selected pick window vertices. Apparatus for implementing pick detect is provided that accomplishes pick detect as part of graphics pipeline processing. In the trivial pick or no pick cases, the apparatus does not slow pipeline operation, while in a non-trivial case, extra processing cycles are required.