Computer graphics pixel processing system

• US 4,873,515 A
• Filed: 10/16/1987
• Issued: 10/10/1989
• Est. Priority Date: 10/16/1987
• Status: Expired due to Term

• Current Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: Dickson, Calvin M., Rushforth, Kevin C.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/108,888
• Time in Patent Office: 725 Days
• Field of Search: 340/728, 340/729, 340/744, 340/751, 340/723, 364/518, 364/521, 364/522
• US Class Current: 345/614
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G09G 5/20 Function-generator circuits, e.g. circle generators line or curve smoothing circuits

Abstract

A line-filtering antialiasing apparatus for a computer graphics display, with a set of parallel pixel processors functioning independently in a line drawing system and with plotting apparatus assigning individual pixels to the processors so as to track to the line. An optimum number of sixteen processors filter proximity data based on the vertical distance from a pixel center to the line center for shading pixels to gray-scale intensity in an area of influence four pixels wide. Line terminations are extended and shaded at the termination area. Pixel values for individual lines are summed to develop a total display image.

Claims

1. A computer graphics system for receiving display data, as in a form to specify a line in a display, said system for providing representative pixel data for said display and comprising:

a plotting unit for providing address data, as to specify a line in said display;

a plurality of parallel processors coupled to said plotting unit, said parallel processors being individually coupled for processing data for individual pixels of said display in stages, each stage treating an array of pixels in columns of a predetermined number of pixels, said columns being aligned individually substantially to said line to track said line, said processors providing display data for individual pixels in sequence and varying as the proximity of a pixel to a specified line; and

means for receiving and storing said display data in an arrangement for display.

2. A system according to claim 1 wherein said columns are of four pixels.

3. A system according to claim 1 comprising two columns.

4. A system according to claim 2 wherein said processors process an array of sixteen pixels.

5. A system according to claim 1 comprising four columns.

6. A system according to claim 1 wherein said processors provide display data modulated in intensity as related to the coordinate distance from pixel to line.

7. A system according to claim 1 further including means to add pixels at an end of said line.

8. A system according to claim 7 further including means to modulate pixels at said end of said line in accordance with values stored in a look-up table.

9. A computer graphics system for receiving display data, as in a form to specify a line in a display, said system for providing representative pixel data for said display and comprising:

a plotting unit for providing address data, as to specify a line in said display;

a plurality of parallel processors coupled to said plotting unit, said parallel processors individually processing data for individual pixels of said display in stages, each stage treating an array of pixels, said processors providing display data for individual pixels in sequence and providing distinct display data at terminations of a said line of reduced intensity and varying as the sum of the coordinate distances; and

means for receiving and storing said display data in an arrangement for display.

10. A system according to claim 9 wherein said processors reduce the intensity representations for said terminations by substantially one-half.

11. A system according to claim 9 wherein said parallel processors comprise address sections for locating pixels, filter sections for shading filter weight signals and intensity sections for modulating intensity signals in accordance with said filter weight signals.

12. A system according to claim 9 further comprising means for processing data for cross-over points between plurality of said lines including means to sum said display data at terminations for said lines for said cross-over points to provide increased intensity.

13. A computer graphics system for receiving display data, as in a form to specify individual lines in display said system for providing representative pixel data for said display and comprising:

a plotting unit for providing address data, as to specify a line in said display;

a plurality of parallel processors coupled to said plotting unit, said parallel processors individually processing data for individual pixels of said display in stages, said processors providing display data for individual pixels in sequence and varying as the proximity of pixel to a specified line; and

means for processing data for cross-over points between a plurality of said lines including means to sum said display data at terminations for said lines for said cross-over points to provide increased intensity.