A first texture is used for determining color and design of a polygon structuring an object rendered upon a two-dimensional screen. A second texture has a pattern of dense distribution of color with a predetermined slant relative to the two-dimensional screen. An rendering processing device first applies a first texture to a polygon structuring an object, and thereafter performs translucent synthesis of a second texture on an object applied with the first texture, thereby making it possible to easily render an image in a hand-drawn illustration style in, for example, home video games and computer graphics.