Abstract: An image generation system includes a vertex split count setting section that performs a vertex split count setting process that sets a vertex split count m, a vertex split processing section that performs a vertex split process on a three-dimensional object OB in an object space using the vertex split count m, a vertex position calculation section that calculates an intersection position of a projection screen SC and a straight line that connects a vertex position of the three-dimensional object OB after the vertex split process and a position of a virtual camera VC, and calculates a vertex position of a drawing object corresponding to the three-dimensional object OB on a drawing buffer based on the calculated intersection position, and a drawing section that draws the drawing object on the drawing buffer based on the vertex position of the drawing object to generate a projection image.

Abstract: A game system, program and image generating method for drawing an object viewed from various angles are provided. The thickness of an outline image of the object is changed depending on the face shape of the object. The outline image is drawn with a thicker outline when an angle ? between a first vector extending from a point on the face toward the viewpoint and a normal vector changes from the right angle with a lower decrement, and drawn with a thinner outline line when the angle ? changes from the right angle with a higher decrement. The outline image is drawn in the vicinity of an area defined by ????90°. An outline texture specified by a texture coordinate, determined based on the inner product between the first vector and the normal vector, is mapped on the object. Another outline image, having constant thickness, is drawn.

Abstract: A game system, program and image generating method which can draw an object viewed from various angles with its varied line thickness of outline are provided. The thickness of the outline image is changed depending on the face shape of the object OB in the vicinity of the outline thereof. The outline image is drawn with a thicker outline when an angle &thgr; between a first vector extending from a point on the face toward the viewpoint and a normal vector changes from the right angle with a lower decrement. On the other hand, the outline image is drawn with a thinner outline line when the angle &thgr; changes from the right angle with a higher decrement. The outline image is drawn in the vicinity of an area defined by &agr;≦&thgr;≦90°. An outline texture specified by a texture coordinate which are determined based on the inner product between the first vector and the normal vector is mapped on the object. Another outline image having a constant thickness is drawn.