Patent ID: 7292242

Claim:
In a rendering pipeline configured for rendering an image from input geometry data including input triangles, a method for clipping an input triangle having three vertices to a first clipping surface that defines a first invisible region, the method comprising: identifying each of the three vertices as being invisible or not invisible based on whether that vertex is in the first invisible region; in the event that exactly one vertex of the input triangle is invisible, performing the acts of: defining a quadrangle having as vertices the two vertices of the input triangle that are not invisible and two clipped vertices, wherein each clipped vertex is located approximately at the intersection of the first clipping surface with one of the edges that terminates at the invisible vertex; selecting three vertices from the four vertices of the quadrangle; and computing a parameter value for an attribute equation using the three selected vertices, wherein the attribute equation defines a non-positional attribute and is used to determine at least in part the appearance of a pixel covered by the input triangle in the rendered image; and rendering the image using the quadrangle and the attribute equation.