System and method of from-region visibility determination and delta-pvs based content streaming using conservative linearized umbral event surfaces

Abstract

A method determines a set of mesh polygons or fragments of the mesh polygons visible from a view region having a plurality of view region vertices, the mesh polygons forming polygon meshes. The method includes determining at least one supporting polygon between the view region and the polygon meshes. The method further includes constructing at least one wedge from the at least one supporting polygon, the at least one wedge extending away from the view region beyond at least the polygon meshes. Further, the method includes determining one or more intersections of the wedges with the mesh polygons. Also, the method includes determining the set of the mesh polygons or fragments of the mesh polygons visible from the view region using the determined one or more intersections of the at least one wedge with the polygon meshes.

I claim: 
     
         1 . A method, conducted on a server, for controlling navigation-based pre-fetch sending of graphics information to a client device, said graphics information including a first set of graphics information visible from a second view region and not visible from a first view region, and said graphics information including a second set of graphics information visible from said second view region and not visible from said first view region, said second set of graphics information having a lower level-of-detail than said first set of graphics information, the method comprising:
 a) determining, using processing circuitry, a first period during which said first set of graphics information will arrive after said client device is scheduled to access said first set of graphics information on said client device; and   b) sending said second set of graphics information during said first period.   
     
     
         2 . The method according to  claim 1 , wherein said navigation-based prefetch comprises:
 receiving, from said client device, information indicating a first viewpoint location at a first instant;   predicting, using processing circuitry and said information indicating said first viewpoint location, a second viewpoint location at a second instant, said second instant later than said first instant;   determining, using the processing circuitry, if said first viewpoint location and said second viewpoint location are in different view regions; and   sending, upon determination that said first viewpoint location and said second viewpoint location are in different view regions, said second set of graphics information.   
     
     
         3 . The method of  claim 1 , wherein said graphics information includes polygons. 
     
     
         4 . The method of  claim 1 , further comprising:
 c) sending additional graphics information during a second period occurring after said first period, said additional graphics information including information used to add detail to said second set of graphics information sent during said first period.   
     
     
         5 . The method of  claim 4 , wherein
 the amount of said additional graphics information sent in the step c) is selected in accordance with a function of an elapsed time period between said first period and said second period, and   the amount of said additional graphics information sent in the step c) is further selected in proportion to the human visual system's ability to perceive said additional graphics information after said elapsed time period.   
     
     
         6 . A method, conducted on a client device, of receiving graphics information from a server, said graphics information including a first set of graphics information visible from a second view region and not visible from a first view region, and said graphics information including a second set of graphics information visible from said second view region and not visible from said first view region, said second set of graphics information having a lower level-of-detail than said first set of graphics information, the method comprising:
 a) determining, using processing circuitry, a first period during which said first set of graphics information will arrive at client device after said client device is scheduled to access said first set of graphics information on said client device; and   b) receiving said second set of graphics information during said first period.   
     
     
         7 . The method of  claim 6 , further comprising:
 c) receiving additional graphics information during a second period occurring after said first period, said additional graphics information including information used to add detail to said second set of graphics information sent during said first period.   
     
     
         8 . The method of  claim 7 , wherein
 the amount of said additional graphics information received in step c) is selected in accordance with a function of an elapsed time period between said first period and said second period, and   the amount of said additional graphics information sent in step c) is further selected in proportion to the human visual system's ability to perceive said additional graphics information after said elapsed time period.