Patent ID: 6304270
Filing Date: 2001-10-16
Classification: G06T

Abstract:
A computer implemented method of determining whether a polygon to be displayed in a computer system is a simple convex polygon comprising the steps of:receiving information defining vertices of the polygon;determining whether the polygon is convex;selecting a starting vertex;determining a direction between a first pair of vertices relative to a predetermined coordinate axis, wherein said first pair of vertices comprises said starting vertex and an adjacent vertex;for successive pairs of vertices:determining a direction relative to said predetermined coordinate axis; anddetermining whether a change in direction has occurred;counting the number of changes in direction;determining a disposition of the starting vertex relative to said predetermined coordinate axis;determining the polygon is a simple convex polygon in response to the number of direction changes being less than or equal to two if the starting vertex is disposed between two other vertices relative to said predetermined coordinate axis and determining the polygon is a simple convex polygon in response to the number of direction changes being equal to one if the starting vertex is not disposed between two other vertices relative to said predetermined coordinate axis; andusing alternate function means to display the polygon in the computer system in response to the step of determining whether the polygon is a simple convex polygon.