| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an image generator capable of shortening processing time by reducing the number of times of access to Z buffers and the number of times of operation for finding a new Z value by reading the Z values only from the region of the Z buffer corresponding to the representative pixel of a sector and the region of the Z buffer corresponding to the adjacent pixel of the sector. SOLUTION: While a polygon is plotted on a certain pixel inside a sector 21, a corresponding bit in paint 26 is set to '1' and when the polygon is not plotted, such a bit is set to '0'. Concerning the pixel corresponding to the bit set to '1' in the paint 26, the Z value is set at a correspondent position inside the Z buffer. In the case of a pixel corresponding to the bit set to '0' inside the paint 26, on the other hand, the contents of the Z value are not specified. Therefore, since the polygon is not plotted while the bit '0' is set to the paint 26, it is not necessary to read the Z value and referring to the unwanted Z buffer can be avoided.</p> |
