Modified method and apparatus for improved occlusion culling in graphics systems
AssigneeNVIDIA Corporation
InventorsEdward C. Greene, Douglas A. Voorhies, Paolo Sabella, John M. Danskin, James M. Van Dyke
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Abstract
A system, method and computer program product are provided for avoiding reading z-values in a graphics pipeline. Initially, near z-values are stored which are each representative of a near z-value on an object in a region. Such region is defined by a tile and a coverage mask therein. Thereafter, the stored near z-values are compared with far z-values computed for other objects in the region. Such comparison indicates whether an object is visible in the region. Based on the comparison, z-values previously stored for image samples in the region are conditionally read from memory.
Claims17
A method for avoiding reading z-values in a graphics pipeline, comprising:
- storing near z-values each representative of a near z-value on an object in a region, wherein the region is defined by a tile and a coverage mask therein;
- comparing the stored near z-values with far z-values computed for other objects in the region, wherein the comparison indicates whether an object is visible in the region;
- and
- based on the comparison, conditionally reading from a z-value buffer z-values previously stored for image samples in the region;
- wherein the reading of the z-values from the z-value buffer is avoided in the graphics pipeline.
A computer program product for avoiding reading z-values in a graphics pipeline, comprising:
- (a) computer code for storing near z-values each representative of a near z-value on an object in a region, wherein the region is defined by a tile and a coverage mask therein;
- (b) computer code for comparing the stored near z-values with far z-values computed for other objects in the region;
- and
- (c) computer code for based on the comparison, conditionally reading from memory z-values previously stored for image samples in the region;
- (d) wherein the comparison indicates whether an object is visible in the region.
A system for avoiding reading z-values in a graphics pipeline, comprising:
- (a) logic for storing near z-values each representative of a near z-value on an object in a region, wherein the region is defined by a tile and a coverage mask therein;
- (b) logic for comparing the stored near z-values with far z-values computed for other objects in the region;
- and
- (c) logic for, based on the comparison, conditionally reading from memory z-values previously stored for image samples in the region;
- (d) wherein the comparison indicates whether an object is visible in the region.
Dependencies are inferred from the claim text.