Polygon anti-aliasing with any number of samples on an irregular sample grid using a hierarchical tiler
AssigneeHewlett-Packard Development Company, L.P.
InventorRonald D Larson
Life of this patent
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Abstract
An apparatus and method of selectively over-sampling image data, anti-aliasing of polygons that produces quality images comparing favorably to full over-sampling techniques while requiring less computation than full over-sampling techniques. Using a hierarchical tiler to perform edge calculations for any given polygon, and then selectively over-sampling pixels along the edge, image quality may be greatly improved through anti-aliasing the polygon edges, with a small increase in computation time or hardware.
Claims13
A method for performing anti-aliasing in a computer graphics display system comprising the steps of:
- a) sub-dividing a display region into sub-pixel regions;
- b) for fewer than all of said sub-pixel regions within said display regions, determining whether a particular sub-pixel region is entirely outside of a primitive, entirely inside of said primitive, or partially inside of said primitive, using an offset grid;
- c) calculating a color for said display region from said sub-pixel region determinations;
- d) displaying said color for said display region;
- e) partitioning said display into display regions;
- f) selecting a display region through which a primitive edge passes;
- and
- g) repeating step f) and steps a) through d) for each display region through which a primitive edge passes.
A computer program storage medium readable by a computer, tangibly embodying a computer program of instructions executable by the computer to perform method steps for anti-aliasing in a computer graphics display system, the steps comprising:
- a) sub-dividing a display region into sub-pixel regions;
- b) for fewer than all of said sub-pixel regions within said display region, determining whether a particular sub-pixel region is entirely outside of a primitive, entirely inside of said primitive, or partially inside of said primitive, using an offset grid;
- c) calculating a color for said display region from said sub-pixel region determinations;
- d) displaying said color for said display region.
- e) partitioning said display into display regions;
- f) selecting a display region through which a primitive edge passes;
- and
- g) repeating step f) and steps a) through d) for each display region through which a primitive edge passes.
A device for anti-aliasing primitives for display by a computer graphics display system comprising:
- a setup block that receives primitive data from a computer graphics front end block and outputs primitive edge data;
- a partition block that partitions said display into regions;
- a calculation block electrically connected with said partition block, that receives said primitive edge data from said setup block, and determines which of said regions contain a primitive edge;
- a sub-pixel partition block electrically connected with said calculation block, that partitions said regions containing a primitive edge into sub-pixel regions;
- a sub-pixel calculation block electrically connected with said sub-pixel partition block, that receives said sub-pixel regions from said sub-pixel partition block and, for fewer than all of said sub-pixel regions, determines whether a particular sub-pixel region is entirely outside of said primitive, entirely inside of said primitive, or partially inside of said primitive;
- a sub-pixel color calculation block electrically connected with said sub-pixel calculation block that receives said sub-pixel determinations from said sub-pixel calculation block and calculates a color data for said region from said sub-pixel region determinations;
- a display unit that receives said color data for said regions from said sub-pixel color calculation block, formats said color data for display, and outputs said formatted color data to a computer graphics display.
Dependencies are inferred from the claim text.