Computer graphics processing and selective visual display system – Computer graphics processing – Three-dimension
Patent
1997-04-08
1999-11-30
Powell, Mark R.
Computer graphics processing and selective visual display system
Computer graphics processing
Three-dimension
345426, 345431, 345441, 345442, G06T 120
Patent
active
059951095
ABSTRACT:
A method for efficient, high quality rendering of a surface patch. The method tests a surface patch for flatness, and if the surface patch is not flat, the method divides the surface patch into a left surface patch and a right surface patch. Otherwise if the surface patch is flat, the method converts the surface patch into triangles. This method can be implemented to operate recursively, thereby ensuring that all portions of the patch are eventually converted into triangles when the portions become small enough to satisfy the flatness condition. A patch tests as flat only if all curves which form the patch do not deviate from straight lines by more than a predetermined tolerance. The division is efficiently performed by determining (i) left patch control points for a first portion of all curves along one axis of the surface patch, and (ii) right patch control points for a second portion of all curves along said axis of the surface patch. The axis of division preferably alternates, so that the dividing is done along a second axis if patch is not flat along the second axis and a preceding division occurred along a first axis. The method also includes tests for backfaced orientation of the patch and external location of the patch. The patch is discarded if it faces away from the viewpoint or does not appear inside the viewing region.
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U.S. application No. 08/810,256 filed Mar. 3, 1997.
Goel Vineet
Vainsencher Leonardo
LSI Logic Corporation
Nguyen Kimbinh T.
Powell Mark R.
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