Pipelined 2D viewport clip circuit
AssigneeSun Microsystems, Inc.
InventorCharles Patton
Life of this patent
Estimating the term…
Abstract
A system and method for performing viewport clipping for multiple viewports using a pipeline. The pixel address coordinates are compared against boundaries of a first viewport window. The results of this comparison, along with the pixel address coordinates, are registered and passed on to the next pipeline stage. There, the pixel address coordinates are compared against the boundaries of a second viewport window. The comparison results are combined with those passed from the previous stage, and the results are again registered. This scheme is repeated until the pixel has been tested against all the viewport window boundaries, with the intermediate results being combined into a single result indicative of whether the pixel is to be passed to the subsequent stages of the graphics pipeline or clipped.
Claims17
A method for comparing a pixel against one or more windows using a pipeline, the method comprising:
- passing said pixel through the pipeline, wherein said pipeline comprises two or more pipeline segments;
- computing window result in each one of said two or more pipeline segments, wherein each one of said two or more pipeline segments corresponds to one of said one or more windows, wherein said window result comprises an indication of inclusion of said pixel within the corresponding one of said one or more windows;
- outputting a window word from each one of said two or more pipeline segments, wherein said outputting said window word comprises, for each of said two or more pipeline segments except for a last pipeline segment, passing said window word to next pipeline segment, wherein said window word comprises said window result and previous window result;
- and
- examining said window word available in the last pipeline segment.
A method comprising:
- supplying window boundary coordinates for a plurality of windows to a computational pipeline, wherein each segment of the computational pipeline corresponds to one of said windows;
- each stage, except for a last segment, of the computation pipeline determining if a corresponding pixel is included in the corresponding window, and passing the corresponding pixel and a result of said inclusion determination to a next segment of the computational pipeline.
A system for determining inclusion of a pixel with respect to each of one or more windows, wherein the pixel comprises a horizontal and a vertical coordinate, wherein each of said one or more windows comprises a first horizontal and a second horizontal coordinate and a first vertical and a second vertical coordinate that define boundaries of each of said one or more windows in a two-dimensional space, the system comprising:
- a pipeline having two or more pipeline segments, wherein each one of said two or more pipeline segments corresponds to one of said one or more windows, wherein each one of said two or more pipeline segments, except for a last of said two or more pipeline segments, is configured to:
- (a) receive the horizontal and vertical coordinates of the pixel, (b) compute a window result indicating whether or not said pixel is located within said corresponding window, and (c) pass the horizontal and vertical coordinates of the pixel and the window result to a next one of said two or more pipeline segments.
Dependencies are inferred from the claim text.