[li] Patent Number: 4,952,922  Date of Patent: Aug. 28, 1990
 PREDICTIVE LOOK AHEAD MEMORY MANAGEMENT FOR COMPUTER IMAGE GENERATION IN SIMULATORS
 Inventors: Arthur F. Griffin, Redondo Beach;
Norton L. Moise, Pacific Palisades, both of Calif.
 Assignee: Hughes Aircraft Company, Los Angeles, Calif.
 Appl. No.: 756,869
 Filed: Jul. 18, 1985
 Int. a.5 G09G 1/18
 U.S. CI 340/729; 364/522
 Field of Search 434/38, 41, 44, 35,
434/37; 364/578, 518, 423, 522; 340/729
 References Cited
FOREIGN PATENT DOCUMENTS
2113056 7/1983 United Kingdom 340/729
2144608 3/1985 United Kingdom 364/522
Primary Examiner—Ian J. Lobo
Attorney, Agent, or Firm—Leonard A. Alkov; Wanda Denson-Low
A method for use with a vehicle simulator which provides for the rapid update of displayed terrain data in areas of non-visible terrain surfaces and terrain image discontinuities. The method is for use with a system which projects a time-varying computer-generated image scene representative of the terrain as viewed from a moving vehicle. The image scene is derived from a digital data base stored in slow speed secondary memory. The method includes the steps of predicting, by means of line-of-sight sampling ray, which segments of the data base could be visible after a predetermined time interval. The data base is accessed for the predicted segments of data and theres segments are retrieved therefrom. The data segments designated are tyhen stored in predetermined memory locations in highspeed main memory. Finally, selected ones of the stored segments are displayed based on the actual vehicle path and position after the predetermined time interval has elapsed.
4 Claims, 6 Drawing Sheets