Reducing fill and improving quality of interlaced displays using multi-sampling

1. A method for filling into a frame buffer for an interlaced display a frame having a first field and a second field, the method comprising the steps of:

(a) calculating a first multi-sample of the first line of the first field, wherein bottom sub-pixels of said first multi-sample are the top sub-pixels of a multi-sample of the identical-numbered line of the second field;

(b) writing said first multi-sample into the frame buffer;

(c) calculating a next multi-sample of the next line of the first field, wherein top sub-pixels of said next multi-sample are the bottom sub-pixels of a multi-sample of the previous line of the second field, and wherein bottom sub-pixels of said next multi-sample are the top sub-pixels of a multi-sample of the identical-numbered line of the second field; and

(d) writing said next multi-sample into the frame buffer;

(e) performing steps (c) and (d) for each line of the first field;

(f) calculating a last multi-sample of the last line of the second field, wherein said last multi-sample consists of sub-pixels of a full multi-sample of the last line of the second field; and

(g) writing said last multi-sample into the frame buffer.

2. A method for providing a frame having a first field and a second field to an interlaced display, the method comprising the steps of:

(a) writing into a frame buffer a multi-sample for each line of the first field;

(b) reading, from said frame buffer, a first multi-sample of the first line of the first field, wherein bottom sub-pixels of said first multi-sample are the top sub-pixels of a multi-sample of the identical-numbered line of the second field;

(c) calculating a resultant line from said first multi-sample of the first line of the first field; and

(d) providing said resultant line to the interlaced display.

3. The method of claim 2 , further comprising the step of:

(e) reading, from said frame buffer, a next multi-sample of the next line of the first field, wherein top sub-pixels of said next multi-sample are the bottom sub-pixels of a multi-sample of the previous line of the second field, and wherein bottom sub-pixels of said next multi-sample are the top sub-pixels of a multi-sample of the identical-numbered line of the second field;

(f) calculating a resultant line from said next multi-sample of the first line of the first field; and

(g) providing said resultant line to the interlaced display.

4. The method of claim 3 , further comprising the step of:

(h) performing steps (e), (f) and(g) for each line of the first field.

5. The method of claim 4 , wherein the frame buffer is refreshed at the same rate that field data is fetched from the frame buffer.

6. A system for providing a frame having a first field and a second field to an interlaced display, comprising:

a buffer for writing a multi-sample for each line of the first field, wherein bottom sub-pixels of each multi-sample are the top sub-pixels of a multi-sample of the identical-numbered line of the second field, and wherein top sub-pixels of each multi-sample are the bottom sub-pixels of a multi-sample of the previous line of the second field;

means for reading each multi-sample from said frame buffer;

means for calculating a resultant line from each multi-sample; and

means for providing each resultant line to the interlaced display.

7. A computer program product comprising a computer useable medium having computer program logic for enabling at least one processor in a computer system to provide a frame having a first field and a second field to an interlaced display, the computer program logic comprising:

first computer readable program code means for causing the computer to write into a frame buffer a multi-sample for each line of the first field;

second computer readable program code means for causing the computer to read from said frame buffer a first multi-sample of the first line of the first field, wherein bottom sub-pixels of said first multi-sample are the top sub-pixels of a multi-sample of the identical-numbered line of the second field;

third computer readable program code means for causing the computer to calculate a resultant line from said first multi-sample of the first line of the first field; and

fourth computer readable program code means for causing the computer to provide said resultant line to the interlaced display.

8. The computer program product of claim 7 , the computer program logic further comprising:

fifth computer readable program code means for causing the computer to read from said frame buffer a next multi-sample of the next line of the first field, wherein top sub-pixels of said next multi-sample are the bottom sub-pixels of a multi-sample of the previous line of the second field, and wherein bottom sub-pixels of said next multi-sample are the top sub-pixels of a multi-sample of the identical-numbered line of the second field;

sixth computer readable program code means for causing the computer to calculate a resultant line from said next multi-sample of the next line of the first field; and

seventh computer readable program code means for causing the computer to provide said resultant line to the interlaced display.

9. The computer program product of claim 8 , the computer program logic further comprising:

eighth computer readable program code means for causing the computer to execute said fifth, said sixth and said seventh computer readable program code means for each multi-sample of each remaining line of the first field.