Method for display rendering by determining the coverage of pixels in polygons

In a computer controlled display system with a display device having an array of pixels, a method for rendering a polygon for display said method comprising the steps of:

• a) determining a coverage of a pixel within said polygon by said polygon by:
• i) determining a first value representative of a distance from a center of said pixel to an edge of said polygon;
• ii) adding a first predetermined value to said first value representative of the distance for said pixel to produce a second value.;
• iii) clamping said second value according to a function which provides a constant second predetermined value if said second value is less than a first predetermined range and which provides the second value if the second value is within said first predetermined range and which provides a constant third predetermined value if said second value is greater than said first predetermined range;
• iv) repeating steps i-iii for each edge of said polygon;
• v) computing the coverage of the pixel by calculating the product of all clamped values corresponding to edges of said polygon;
• b) determining coverages of each pixel of said polygon;
• c) storing a plurality pixel values in memory, wherein said pixel values are a function of said coverage;
• d) generating electrical signals to actuate pixels of said polygon according to said pixel values;
• e) displaying said polygon on a display device.