Method and apparatus for fast quadrilateral generation in a computer graphics system

In a computer graphics system including a fill scan converter for generating pixel data representative of a quadrilateral in response to plane equation data, a method for generating the plane equation data comprising the steps of:

• receiving vertex data representing the quadrilateral;
• dividing the quadrilateral into vertex data representative of a first triangle and a second triangle;
• generating plane equation data for the first triangle, including shared data;
• providing the plane equation data for the first triangle to the fill scan converter for generating pixel data representative of the quadrilateral;
• generating plane equation data for the second triangle using at least some of the shared data;
• and
• providing the plane equation data for the second triangle to the fill scan converter for generating pixel data representative of the quadrilateral.

In a computer graphics system including a fill scan converter for generating pixel data representative of a quadrilateral in response to plane equation data, an apparatus for generating the plane equation data comprising:

• means for receiving vertex data representing the quadrilateral;
• means for dividing the quadrilateral into vertex data representative of a first triangle and a second triangle;
• means for generating plane equation data for the first triangle, including shared data;
• means for providing the plane equation data for the first triangle to the fill scan converter;
• means for generating plane equation data for the second triangle using at least some of the shared data;
• and
• means for providing the plane equation data for the second triangle to the fill scan converter for generating pixel data representative of the quadrilateral.