non photorealistic rendering of contours

摘要

The object of the present invention is to draw a natural contour line in a tuned object and perform clear tuned representation. For each tuned object existing in a virtual three-dimensional space, a reference width 402 that is determined in accordance with a reference size of each tuned object projected on a virtual screen is set, assuming that a distance from a viewing point of a virtual camera (or a distance from the virtual screen) used for perspective transforming the virtual three-dimensional space is a predetermined reference distance Db. The line width W of the contour line of each tuned object is calculated by using an equation of "W = RNDUP (a x Eb x Db / D) " based on a distance D from the viewing point 303 to a reference point of each tuned object and coefficient "a" determined in accordance with the progress status of a game. Here, RNDUP is a function for rounding up the fractional part to the nearest integer.