| 摘要 |
A three-dimensional object (V1) is an object drawn by subjecting two-dimensional vertex data (Pi) to an extrusion operation in the H direction. If the height in the H direction of the three-dimensional object (V1) is denoted by h1, the coordinates of vertex data (Qi) constituting an upper surface (Su1) is Qi = (xi, yi, h1). A three-dimensional object (V2) other than the three-dimensional object (V1) is an object drawn by subjecting the plane (S2) formed by new two-dimensional vertex data (P11 to P14) to an extrusion operation in the H direction. An upper surface (Su2) of the three-dimensional object (V2) is formed by vertex data (Q11 to Q14). A drawing unit (106) gives a common modulation factor (Ku) to the upper surfaces (Su1, Su2) to calculate the illumination color (Cu1) of the upper surface (Su1) and the illumination color (Cu2) of the upper surface (Su2). |
