The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 16, 2001
Filed:
Apr. 23, 1997
Vimal Parikh, Fremont, CA (US);
Carroll Philip Gossett, Mountain View, CA (US);
Siligon Graphics, Inc., Mountain View, CA (US);
Abstract
The present invention provides a method for shading an image comprised of polygons in a graphics system. Each vertex of a polygon has x, y, and z coordinates, a normalized light source vector (L), a normalized surface normal vector (N), a normalized half-angle vector (H), and a specular exponent (s). The present invention selects a polygon and computes the angles between vectors N and L for each of the vertices. It also computes the difference terms between vectors N and H for each of the vertices. Then, the method of the present invention selects a pixel in the polygon to shade. It interpolates an angle between vectors N and L for the pixel based on the angles evaluated for the vertices. Based on the interpolated angle, a diffuse term for the pixel is determined. The present invention also determines a specular term for the selected pixel. It first interpolates a difference term between vectors N and H for the pixel based difference terms for each of the vertices. The specular term for the pixel is then determined from the difference term at the pixel. The method of the present invention then determines a color for the pixel by incorporating the diffuse term and the specualar term according to a Phong lighting equation.