Predictive look ahead memory management for computer image generation in simulators
First Claim
1. A method for use in a system which projects a time varying computer generated image scene representation of terrain as viewed from a moving vehicle which traverses a simulated path, said image scene being derived from a data base stored in secondary storage, said method comprising the steps of:
- predicting a set of possible future positions of the vehicle after a predetermined time interval, said predicted positions being calculated based on the motion dynamics of the vehicle;
for a number of possible future positions, sampling the terrain data base with line-of-sight rays projected from the position of the vehicle operator'"'"'s eye into the data base in cartesian coordinate space;
marking the data at the point of sample ray terrain surface intersection and the data for surfaces adjacent to that point as likely candidates for near-future display update;
accessing the marked data and storing them in high speed main memory; and
displaying selected ones of the stored data segments based on the simulated path and position of the vehicle after the predetermined time interval has elapsed;
whereby a rapid update of the displayed terrain in the near future is achieved.
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Abstract
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 these segments are retrieved therefrom. The data segments designated are then stored in predetermined memory locations in high-speed 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.
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Citations
4 Claims
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1. A method for use in a system which projects a time varying computer generated image scene representation of terrain as viewed from a moving vehicle which traverses a simulated path, said image scene being derived from a data base stored in secondary storage, said method comprising the steps of:
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predicting a set of possible future positions of the vehicle after a predetermined time interval, said predicted positions being calculated based on the motion dynamics of the vehicle; for a number of possible future positions, sampling the terrain data base with line-of-sight rays projected from the position of the vehicle operator'"'"'s eye into the data base in cartesian coordinate space; marking the data at the point of sample ray terrain surface intersection and the data for surfaces adjacent to that point as likely candidates for near-future display update; accessing the marked data and storing them in high speed main memory; and displaying selected ones of the stored data segments based on the simulated path and position of the vehicle after the predetermined time interval has elapsed; whereby a rapid update of the displayed terrain in the near future is achieved. - View Dependent Claims (2, 3, 4)
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Specification