Method and apparatus for anti-aliasing for video applications
View Patent ↗Antialiasing method and apparatus for video applications. A method for antialiasing a video graphic. A determination is first made as to the relative position of a desired pixel being within the polygon and proximate to the edge of the polygon. Once the relative position is known, then a determination is made as to whether it meets a first predetermined condition or a second predetermined condition. If the relative position meets the first condition, then the color of at least an adjacent pixel is blended with the color of the desired pixel in a predetermined proportion. If the relative position meets the second predetermined condition, then the color of at least an adjacent pixel is blended with the color of the desired pixel in a predetermined proportion.
1. A computer implemented method for anti-aliasing pixels proximate to an edge of a polygon displayed on a display, comprising the steps of:
determining if the position of a desired pixel is located within the polygon;
if determined to be within the polygon, determining if the desired pixel is proximate to at least one of the edges of the polygon and within a predetermined pixel width thereof;
determining if the position meets a first predetermined condition or a second predetermined condition;
if the position meets the first predetermined condition, then blending with the color of the desired pixel the color of at least an adjacent pixel in a first predetermined proportion and in a first predetermined direction;
if the position meets the second predetermined condition, then blending with the color of at least an adjacent pixel the color of the desired pixel in a second predetermined proportion and in a second predetermined direction; and
displaying at least the desired and adjacent pixels.
2. The method of claim 1 , wherein the pixel is located outwardly from the triangle relative to the desired pixel.
3. The method of claim 2 , wherein the first and second predetermined portions are based on the position of the desired pixel relative to the edge of the polygon.
4. The method of claim 1 , wherein the polygon is a triangle having three edges.
5. The method of claim 1 , wherein each pixel has a sample point and the step of determining if a desired pixel is located within the polygon comprises determining if the sample point is located within the polygon.
6. The method of claim 5 , wherein the step of determining if the position of the desired pixel is proximate to the at least one of the edges of the polygon comprises determining if the sample point is within a predetermined distance of the at least one of the edges of the polygon.
7. The method of claim 6 , wherein the step of determining if the position meets a first predetermined condition comprises the step of determining if the desired pixel has a sample point thereof located within the polygon and if a portion thereof overlaps the at least one edge of the polygon.
8. The method of claim 6 , wherein the step of determining if the position meets the second predetermined condition comprises determining if an adjacent pixel to the desired pixel overlaps the at least one edge of the polygon and a sample point of the adjacent pixel is not within the polygon.
9. The method of claim 6 , wherein the sample point is equal to substantially the centerpoint of the pixel.
10. The method of claim 9 , wherein the step of determining if the position meets a first predetermined condition comprises determining if the centerpoint of the desired pixel is disposed from the at least one edge of the polygon by a distance of at least one-half of a full pixel width and less than or equal to a full pixel width.
11. The method of claim 9 , wherein the step of determining if the position meets the second predetermined condition comprises the step of determining if the centerpoint of the desired pixel has a distance from the at least one edge of the polygon of less than or equal to one-half of full pixel width.