Method and apparatus for reducing illumination calculations through efficient visibility determination
First Claim
1. A computer graphics system for processing data for a sequence of graphical primitives and having a frame buffer coupled to a display device, comprising:
- means for generating a plurality of pixels for each primitive in said sequence of graphical primitives;
means for determining whether respective current primitives in said sequence of graphical primitives are hidden or visible relative other primitives in said sequence of graphical primitives, a hidden determination indicating that no pixel of said current primitive will be displayed on said display device; and
means for performing graphical calculations for only primitives of said current primitives determined as visible, said means for performing graphical calculations performing graphical calculations for each of said current primitives when, and as, determined to be visible.
0 Assignments
0 Petitions
Accused Products
Abstract
A computer graphics system reduces the number of lighting calculations required to render a scene having objects illuminated by light sources by classifying each primitive for objects in an illuminated scene as either hidden or visible using a z-buffer. In a first approach, only one pass is made through the display list of primitives for the scene, and lighting calculations are performed only for primitives classified as visible. In a second approach, two passes are made through the display list. In the first pass, the display list is fully traversed to set-up the z-buffer, and no lighting calculations are performed. When the second pass of the display list is performed, each primitive is classified as hidden or visible, and lighting calculations are performed for each primitive classified as visible as the display list is traversed. Lighting calculations may be performed using either Gouraud or Phong shading.
103 Citations
27 Claims
-
1. A computer graphics system for processing data for a sequence of graphical primitives and having a frame buffer coupled to a display device, comprising:
-
means for generating a plurality of pixels for each primitive in said sequence of graphical primitives; means for determining whether respective current primitives in said sequence of graphical primitives are hidden or visible relative other primitives in said sequence of graphical primitives, a hidden determination indicating that no pixel of said current primitive will be displayed on said display device; and means for performing graphical calculations for only primitives of said current primitives determined as visible, said means for performing graphical calculations performing graphical calculations for each of said current primitives when, and as, determined to be visible. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. In a computer graphics system having a frame buffer coupled to a display device, a method for processing data for a sequence of graphical primitives, comprising the steps of:
-
generating a plurality of pixels for each primitive in said sequence of graphical primitives; determining whether respective current primitives in said sequence of graphical primitives are hidden or visible relative other primitives in said sequence, a hidden determination indicating that no pixel of said current primitive will be displayed on said display device; and performing graphical calculations for only primitives of said current primitives determined as visible, said graphical calculations being performed for each of said current primitives when, and as, determined to be visible. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
-
Specification