Z buffer bandwidth reductions via split transactions
June 10, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesFilling processing apparatus and method Method for executing graphics Z-compare and pixel merge instructions in a data processor Polygon renderer which determines the coordinates of polygon edges to sub-pixel resolution in the X,Y and Z coordinates directions 5301263 Z-subdivision for improved texture mapping Sorting processor Imaging and graphics processing system Precision Z-interpolation method and apparatus Patent #: 5542025 InventorApplicationNo. 662426 filed on 06/10/1996US Classes:345/422Z buffer (depth buffer)ExaminersPrimary: Fetting, Anton W.Attorney, Agent or FirmInternational ClassG06T 015/40AbstractIn computer graphics systems, a view of scene of primitives is represented by pixel data associated with a set S of pixels. The present invention identifies whether a given primitive is visible at the set S of pixels by storing in a buffer, for each pixel P belonging to set S, a depth value Zold associated with the pixel P. The depth value Zold is partitioned into a plurality of portions including a most significant portion and at least one less significant portion. The buffer comprises a plurality of contiguous blocks each storing corresponding portions of the depth value Zold for a given set SP of consecutive pixels belonging to set S. A set SQ of consecutive pixels belonging to set S that cover the given primitive is determined. The most significant portion of the depth value Zold of the set SQ of consecutive pixels are fetched from the buffer. For each pixel Q belonging to set SQ, the most significant portion of the depth value Zold of the particular pixel is compared to the most significant portion of the computed depth value Znew of the particular pixel to determine if one of three conditions is satisfied: a) the given primitive is visible at the particular pixel, b) the given primitive is hidden at the particular pixel, or c) it is undetermined whether the given primitive is either visible or hidden at the particular pixel. If condition a) is satisfied, the blocks of the buffer associated with the particular pixel is updated to store the computed depth value Znew of the particular pixel. If condition b) is satisfied, the processing ends with respect to the particular pixel. If condition c) is satisfied, the fetching step and comparing step above is repeated for the next less significant portion of the depth values Zold and Znew associated with the particular pixel until the least significant portion of the depth values Zold and Znew has been processed.Other References
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