| 摘要 |
PURPOSE:To improve the efficiency of computer graphics (CG) by deciding the front and back of the surface with the use of an inner product sign between a sight vector against an object and the normal of the surface of the object and performing the shading only in the surface. CONSTITUTION:When a four-side vector a, b, c, d forming the surface of the object is supplied by the data from the shape input device and an input device of shape position or the like, the normal of the surface is obtained by a formula (I). The inner product between this normal and the sight vector is obtained, and when the inner product is more than 0, it is decided as the back surface and removed from the shading object. When the inner product is negative, it is judged as the front surface, and the projection picture is prepared based on write information and camera information while reading them as shading object surface. Thus, the efficiency of CG picture production can be improved. |
